Co-reporter:Isabelle R. Miousse, Charles M. Skinner, Haixia Lin, Laura E. Ewing, Stanley D. Kosanke, D. Keith Williams, Bharathi Avula, Ikhlas A. Khan, Mahmoud A. ElSohly, Bill J. Gurley, Igor Koturbash
Food and Chemical Toxicology 2017 Volume 109, Part 1(Volume 109, Part 1) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.fct.2017.08.025
•Dietary supplement OxyELITE Pro - New Formula (OEP-NF) was linked to severe liver injuries in the United States.•Hepatotoxicity of OEP-NF was assessed in outbred (CD-1) and inbred (B6C3F1) mouse strains.•OEP-NF produced histological, biochemical and molecular alterations that are characteristic to liver injury.•OEP-NF-induced weight loss was transitory, followed by body weight gain in all experimental groups.•These findings bolster concerns for the safety and efficacy of OEP-NF, and similar products, in humans.Herbal dietary supplements have gained wide acceptance as alternatives to conventional therapeutic agents despite concerns regarding their efficacy and safety. In 2013, a spate of severe liver injuries across the United States was linked to the dietary supplement OxyELITE Pro-New Formula (OEP-NF), a multi-ingredient product marketed for weight loss and exercise performance enhancement. The principal goal of this study was to assess the hepatotoxic potential of OEP-NF in outbred and inbred mouse models. In an acute toxicity study, significant mortality was observed after administering 10X and 3X mouse-equivalent doses (MED) of OEP-NF, respectively. Increases in liver/body weight ratio, ALT and AST were observed in female B6C3F1 mice after gavaging 2X and 1.5X MED of OEP-NF. Similar findings were observed in a 90-day feeding study. These alterations were paralleled by altered expression of gene- and microRNA-signatures of hepatotoxicity, including Cd36, Nqo1, Aldoa, Txnrd1, Scd1 and Ccng1, as well as miR-192, miR-193a and miR-125b and were most pronounced in female B6C3F1 mice. Body weight loss, observed at week 1, was followed by weight gain throughout the feeding studies. These findings bolster safety and efficacy concerns for OEP-NF, and argue strongly for implementation of pre-market toxicity studies within the dietary supplement industry.
Co-reporter:Hanwen Yuan, Jianping Zhao, Mei Wang, Shabana I. Khan, Chunmei Zhai, Qiongming Xu, Jianhua Huang, Caiyun Peng, Guanghua Xiong, Wei Wang, Ikhlas A. Khan
Fitoterapia 2017 Volume 121(Volume 121) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.fitote.2017.07.013
Four new benzophenone glycosides named as aquilaside A–D (1–4) along with five known compounds (5–9) were isolated from the methanol extract of the flower buds of Aquilaria sinensis. Their structures were elucidated on the basis of 1D and 2D NMR and mass spectroscopic analyses. All purified compounds were evaluated for their anti-inflammatory and cytotoxic activities. Aquilasides B and C displayed moderate cytotoxicity against SK-MEL cells with IC50 of 17.0 and 12.0 μM and weak NF-κB inhibitive activity at 100 μM with 30% and 60%, respectively.Download high-res image (279KB)Download full-size image
Co-reporter:Fazila Zulfiqar, Shabana I. Khan, Samir A. Ross, Zulfiqar Ali, Ikhlas A. Khan
Phytochemistry Letters 2017 Volume 20(Volume 20) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.phytol.2017.04.027
•Phytochemical investigation of Epimedium grandiflorum is discussed.•Two new prenylated flavonol glycosides and 28 previously known compounds were isolated.•Structure elucidation was achieved by means of NMR and mass spectral data.•Cytotoxicity, anti-inflammatory, and metabolic disorder studies are described.Two new prenylated flavonol glycosides, epimedigrandiosides A and B (1 and 2), and 28 previously known compounds including prenylated flavonol derivatives, flavonol glycoside, megastigmanes, phenyl alkanoids, sesquiterpenoid glycoside, lignan, and hexene glucoside were isolated from the methanol extract of Epimedium grandiflorum. Structure elucidation was achieved by means of spectroscopic and spectrometric techniques including 1D and 2D NMR and HRESIMS. The absolute configuration of sugars was determined by chemical methods Structure elucidation of 3‴-carbonyl-2″-β-l-quinovosyl icariin (19) was not previously described, so its 1H and 13C NMR data were reported for the first time. The methanol extract and the isolated compounds were evaluated for their activity towards several targets related to inflammation and metabolic disorder including NF-κB, iNOS, PPARα and PPARγ. Moreover, their cytotoxic activity against four cancer cell lines (SK-MEL, KB, BT-549, SK-OV-3) and two noncancerous kidney cell lines (LLC-PK1 and Vero) were also evaluated.Download high-res image (125KB)Download full-size image
Co-reporter:Ahmed A. Zaki, Zulfiqar Ali, Yan-Hong Wang, Yasser A. El-Amier, Shabana I. Khan, Ikhlas A. Khan
Steroids 2017 Volume 125(Volume 125) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.steroids.2017.06.003
•Seven steroidal saponins were isolated from Panicum turgidum.•Three bidesmosidic cholestane-type and one spirostane-type steroidal glycosides were found new.•Spirostane-type steroidal glycosides showed cytotoxicity.Three new bidesmosidic cholestane-type steroidal glycosides, 16-O-β-d-glucopyranosyl-cholest-5-en-3β,16β-diol-22-one-3-O-α-l-rhamnopyranosyl-(1 → 2)-O-[(β-d-glucopyranosyl(1 → 4)]-O-β-d-glucopyranoside (1), 16-O-β-d-glucopyranosylcholest-5-en-3β,16β-diol-22-one-3-O-α-l-rhamnopyranosyl-(1 → 2)-O-β-d-glucopyranoside (2), and 16-O-β-d-glucopyranosylcholestan-3β,16β-diol-6,22-dione-3-O-α-l-rhamnopyranosyl-(1 → 2)-O-β-d-glucopyranoside (3) were isolated from a methanolic extract of Panicum turgidum. In addition four known compounds, pennogenin 3β-O-α-l-rhamnopyranosyl-(1 → 2)-O-[α-l-rhamnopyranosyl-(1 → 4)-O-α-l-rhamnopyranosyl-(1 → 4)]-O-β-d-glucopyranoside (4), yamogenin 3β-O-α-l-rhamnopyranosyl-(1 → 2)-O-[α-l-rhamnopyranosyl-(1 → 4)]-O-β-d-glucopyranoside (5), yamogenin 3β-O-α-l-rhamnopyranosyl-(1 → 2)-O-[α-l-rhamnopyranosyl-(1 → 4)-O-α-l-rhamnopyranosyl-(1 → 4)]-O-β-d-glucopyranoside (6), and pennogenin 3β-O-α-l-rhamnopyranosyl-(1 → 2)-O-[α-l-rhamnopyranosyl-(1 → 4)]-O-β-d-glucopyranoside (7) were also isolated and characterized. Their structures were established using extensive spectroscopic methods including 1D and 2D NMR and HRESIMS. The isolated compounds were screened for cytotoxicity towards a panel of mammalian cell lines and 4–7 were found to be cytotoxic.Download high-res image (130KB)Download full-size image
Co-reporter:Mika B. Jekabsons, Hoda M. Gebril, Yan-Hong Wang, Bharathi Avula, Ikhlas A. Khan
Neurochemistry International 2017 Volume 109(Volume 109) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.neuint.2017.03.020
•Reverse non-oxidative PPP flux was incorporated in a13C metabolic flux model.•The model was applied to cerebellar granule neurons from neonatal rat brains.•The oxidative and reverse non-oxidative PPP consumed 39% of the glucose.•Glucose consumption by the pentose cycle was negligible.•The updated model offers advantages to assessing pathway fluxes.A hexose phosphate recycling model previously developed to infer fluxes through the major glucose consuming pathways in cultured cerebellar granule neurons (CGNs) from neonatal rats metabolizing [1,2–13C2]glucose was revised by considering reverse flux through the non-oxidative pentose phosphate pathway (PPP) and symmetrical succinate oxidation within the tricarboxylic acid (TCA) cycle. The model adjusts three flux ratios to effect 13C distribution in the hexose, pentose, and triose phosphate pools, and in TCA cycle malate to minimize the error between predicted and measured 13C labeling in exported lactate (i.e., unlabeled, single-, double-, and triple-labeled; M, M1, M2, and M3, respectively). Inclusion of reverse non-oxidative PPP flux substantially increased the number of calculations but ultimately had relatively minor effects on the labeling of glycolytic metabolites. From the error-minimized solution in which the predicted M-M3 lactate differed by 0.49% from that measured by liquid chromatography-triple quadrupole mass spectrometry, the neurons exhibited negligible forward non-oxidative PPP flux. Thus, no glucose was used by the pentose cycle despite explicit consideration of hexose phosphate recycling. Mitochondria consumed only 16% of glucose while 45% was exported as lactate by aerobic glycolysis. The remaining 39% of glucose was shunted to pentose phosphates presumably for de novo nucleotide synthesis, but the proportion metabolized through the oxidative PPP vs. the reverse non-oxidative PPP could not be determined. The lactate exported as M1 (2.5%) and M3 (1.2%) was attributed to malic enzyme, which was responsible for 7.8% of pyruvate production (vs. 92.2% by glycolysis). The updated model is more broadly applicable to different cell types by considering bi-directional flux through the non-oxidative PPP. Its application to cultured neurons utilizing glucose as the sole exogenous substrate has demonstrated substantial oxygen-independent glucose utilization by aerobic glycolysis as well as the oxidative PPP and/or reverse non-oxidative PPP, but negligible glucose consumption by the pentose cycle.
Co-reporter:Cristina Avonto, Diego Rua, Pradeep B. Lasonkar, Amar G. Chittiboyina, Ikhlas A. Khan
Toxicology and Applied Pharmacology 2017 Volume 318(Volume 318) pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.taap.2017.01.009
•Fractions of German chamomile tested positive in the KeratinoSens™ assay.•Three compounds containing structural alerts were isolated and tested with in chemico methods.•The polyacetylene tonghaosu was found to be unstable and categorized as potential pre-hapten.•A degradation product of tonghaosu tested as positive dermal sensitizer in animal studies.German chamomile is one of the most popular herbal ingredients used in cosmetics and personal care products. Allergic skin reactions following topical application of German chamomile have been occasionally reported, although it is not fully understood which of the chemical constituents is responsible for this adverse effect. In the present work, three candidate sensitizers were isolated from German chamomile based on activity-guided fractionation of chamomile extracts tested using the in vitro KeratinoSens™ assay. The compounds were identified as the polyacetylene tonghaosu (1), and both trans- and cis-glucomethoxycinnamic acids (2 and 3). These three compounds were classified as non- to weakly reactive using in chemico methods; however, aged tonghaosu was found to be more reactive when compared to freshly isolated tonghaosu. The polyacetylene (1) constituent was determined to be chemically unstable, generating a small electrophilic spirolactone, 1,6-dioxaspiro[4.4]non-3-en-2-one (4), upon aging. This small lactone (4) was strongly reactive in both in chemico HTS- and NMR-DCYA methods and further confirmed as a potential skin sensitizer by Local Lymph Node Assay (LLNA).
Co-reporter:Zhihao Zhang, Zulfiqar Ali, Shabana I. Khan, Ikhlas A. Khan
Food Chemistry 2016 Volume 202() pp:262-268
Publication Date(Web):1 July 2016
DOI:10.1016/j.foodchem.2015.12.039
•Seven new monacolins were isolated.•Structure elucidation was achieved by means of NMR spectral data and mass.•Compounds were evaluated for their cytotoxic activity.Seven new monacolins, monacolins Q–S (1–3), α,β-dehydromonacolin S (4), 3α-hydroxy-3,5-dihydromonacolin L (5), 3β-hydroxy-3,5-dihydromonacolin L (6), and α,β-hydromonacolin Q (7) were isolated and characterized from the methanol extract of red yeast rice. In addition, six known monacolins, α,β-dehydrodihydromonacolin K (8), dehydromonacolin K (9), dehydromonacolin L (10), monacolin K (11), dihydromonacolin K (12), dihydromonacolin L (13) and two compounds other than monacolins (14, 15) were also isolated. Structure elucidation of the isolates was achieved by means of NMR and mass spectroscopic data analyses. Compounds 1–5, 8, 9, 11, and 13 were evaluated for their cytotoxic activity against four cancer cell lines (SK-MEL, KB, BT-549, SK-OV-3) and two noncancerous kidney cell lines (LLC-PK1 and Vero). Monacolin Q (1), monacolin R (2) α,β-dehydrodihydromonacolin K (8), dehydromonacolin K (9), and monacolin K (11) showed cytotoxicity to most of these cell lines in terms of inhibition of cell proliferation. The cytotoxicity of monacolin K (11) was the most potent among all the tested monacolins.
Co-reporter:Cristina Avonto, Amar G. Chittiboyina, Mei Wang, Yelkaira Vasquez, Diego Rua, and Ikhlas A. Khan
Chemical Research in Toxicology 2016 Volume 29(Issue 7) pp:1108
Publication Date(Web):June 10, 2016
DOI:10.1021/acs.chemrestox.5b00530
Tea tree oil (TTO) is an essential oil obtained from the leaves of Melaleuca alternifolia, M. linariifolia, or M. dissitiflora. Because of the commercial importance of TTO, substitution or adulteration with other tea tree species (such as cajeput, niaouli, manuka, or kanuka oils) is common and may pose significant risks along with perceived health benefits. The distinctive nature, qualitative and quantitative compositional variation of these oils, is responsible for the various pharmacological as well as adverse effects. Authentic TTOs (especially aged ones) have been identified as potential skin sensitizers, while reports of adverse allergic reactions to the other tea trees essential oils are less frequent. Chemical sensitizers are usually electrophilic compounds, and in chemico methods have been developed to identify skin allergens in terms of their ability to bind to biological nucleophiles. However, little information is available on the assessment of sensitization potential of mixtures, such as essential oils, due to their complexity. In the present study, 10 “tea tree” oils and six major TTO constituents have been investigated for their sensitization potential using a fluorescence in chemico method. The reactivity of authentic TTOs was found to correlate with the age of the oils, while the majority of nonauthentic TTOs were less reactive, even after aging. Further thio-trapping experiments with DCYA and characterization by UHPLC-DAD-MS led to the identification of several possible DCYA-adducts which can be used to deduce the structure of the candidate reactive species. The major TTO components, terpinolene, α-terpinene, and terpinene-4-ol, were unstable under accelerated aging conditions, which led to the formation of several DCYA-adducts.
Co-reporter:Ahmed A. Zaki;Zulfiqar Ali;Yasser A. El-Amier;Ikhlas A. Khan
Magnetic Resonance in Chemistry 2016 Volume 54( Issue 9) pp:771-773
Publication Date(Web):
DOI:10.1002/mrc.4446
Co-reporter:Bharathi Avula, Satyanarayanaraju Sagi, Yan-Hong Wang, Jerry Zweigenbaum, Mei Wang, Ikhlas A. Khan
Food Chemistry 2015 Volume 178() pp:136-148
Publication Date(Web):1 July 2015
DOI:10.1016/j.foodchem.2015.01.053
•UHPLC–QToF-MS method was developed for screening of pyrrolizidine alkaloids (PAs).•Different plant parts of 37 botanicals and 7 dietary supplements were used for study.•PAs were detected in plants from three different families, viz., Asteraceae, Boraginaceae and Fabaceae.•Most of the plants investigated contained macrocyclic diesters based on retronecine as their major alkaloids.•Out of 7 dietary supplements analyzed, 5 showed for the presence of PAs.The UHPLC–QToF-MS analysis of pyrrolizidine alkaloids (PAs) from various parts of 37 botanicals and 7 products was performed. A separation by LC was achieved using a reversed-phase column and a gradient of water/acetonitrile each containing formic acid as the mobile phase. MS–MS detection was used because of its high selectivity, and ability to provide structural information. Free base and N-oxides were observed by this method. PAs were analyzed and detected in plants from three different families, viz., Asteraceae, Boraginaceae and Fabaceae. The Asteraceae family was found to contain senecionine and lycopsamine type PAs. The Boraginaceae family contained lycopsamine and heliotrine type PAs and the Fabaceae family contained senecionine and monocrotaline type PAs. These PAs may serve as important markers for the detection of these plant materials in food and dietary supplements. PAs were identified in 44 samples by comparing their retention times, accurate mass and mass fragmentation patterns with those of 25 reference standards.
Co-reporter:Mei Wang, Jianping Zhao, Bharathi Avula, Yan-Hong Wang, Amar G. Chittiboyina, Jon F. Parcher, and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2015 Volume 63(Issue 10) pp:2674-2682
Publication Date(Web):February 28, 2015
DOI:10.1021/acs.jafc.5b00147
GC/MS, chiral GC/MS, and chemometric techniques were used to evaluate a large set (n = 104) of tea tree oils (TTO) and commercial products purported to contain TTO. Twenty terpenoids were determined in each sample and compared with the standards specified by ISO-4730-2004. Several of the oil samples that were ISO compliant when distilled did not meet the ISO standards in this study primarily due to the presence of excessive p-cymene and/or depletion of terpinenes. Forty-nine percent of the commercial products did not meet the ISO specifications. Four terpenes, viz., α-pinene, limonene, terpinen-4-ol, and α-terpineol, present in TTOs with the (+)-isomer predominant were measured by chiral GC/MS. The results clearly indicated that 28 commercial products contained excessive (+)-isomer or contained the (+)-isomer in concentrations below the norm. Of the 28 outliers, 7 met the ISO standards. There was a substantial subset of commercial products that met ISO standards but displayed unusual enantiomeric +/– ratios. A class predictive model based on the oils that met ISO standards was constructed. The outliers identified by the class predictive model coincided with the samples that displayed an abnormal chiral ratio. Thus, chiral and chemometric analyses could be used to confirm the identification of abnormal commercial products including those that met all of the ISO standards.
Co-reporter:Bharathi Avula, Mei Wang, Satyanarayanaraju Sagi, Pieter A. Cohen, Yan-Hong Wang, Pradeep Lasonkar, Amar G. Chittiboyina, Wei Feng, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2015 Volume 115() pp:159-168
Publication Date(Web):10 November 2015
DOI:10.1016/j.jpba.2015.07.004
•1,3-dimethylbutylamine (DMBA), is a pressor amine.•HPTLC, chiral-GC–MS and UHPLC-QToF-MS methods developed for analysis of DMBA.•25 samples of Camellia sinensis tea leaves and 13 dietary supplements tested for DMBA.•11 supplements contained DMBA in racemic form and ranged from 0.1 to 214 mg/daily dose.1,3-dimethylbutylamine (DMBA), is a CNS stimulant, which has recently been identified in multiple dietary supplements and sometimes labeled as a natural constituent of Pouchung tea. DMBA is an homologue of 1,3-dimethylamylamine (DMAA) which the US Food and Drug Administration has attempted to remove from all dietary supplements after DMAA consumption was linked to strokes, heart disease, and sudden death. To address questions concerning the natural origin of DMBA, three independent analytical methods were developed for analyzing authentic tea samples and dietary supplements. A high performance thin layer chromatography (HPTLC) method was developed for the fast screening and chemical fingerprint analysis. Chiral Gas Chromatography–Mass Spectrometry (GC–MS) was used to determine the enantiopurity and a validated Ultra-High Performance Liquid Chromatography-Quadrupole Time of Flight Mass Spectrometry (UHPLC-QToF-MS) method was developed for the quantification of DMBA. Using these techniques the presence of DMBA was confirmed using a reference standard and was not detected in any of 25 authentic or commercial samples of Camellia sinensis tea leaves (green tea, black tea, Oolong tea, and Pouchung tea). Of 13 dietary supplements tested, 11 contained DMBA in racemic form and ranged from 0.1 to 214 mg per daily dose.
Co-reporter:Amar G. Chittiboyina, Cristina Avonto, Diego Rua, and Ikhlas A. Khan
Chemical Research in Toxicology 2015 Volume 28(Issue 9) pp:1704
Publication Date(Web):July 30, 2015
DOI:10.1021/acs.chemrestox.5b00098
Evaluating consumer products for potentially harmful side effects of chemical ingredients is important for the protection of both the consumer and those involved in the manufacturing process. In order to assess the risk potential of chemicals, regulatory agencies have encouraged the development of several in silico, in vitro, and in chemico methods as alternatives to eliminate or minimize the use of animals. To add structural information to the existing in chemico methods, an NMR-based method is proposed for probing the reactivity and classification of the potential electrophiles (E) using a model thiol, DCYA, as a nucleophile. The major advantage of the NMR method is the quantitation of the actual adduct, DCYA-E. The degree of reaction is here provided as a direct measurement of adduct formation and/or electrophile depletion, in contrast to other in chemico assays, e.g., ADRA and DPRA, where the reactivity is inferred from the quantification of the test nucleophile depletion. Moreover, the developed NMR method should serve as a qualitative and quantitative tool in understanding the site of reaction and other structural information associated with test sensitizer. This is particularly valuable and advantageous over methods encouraged by regulatory agencies, which merely provide quantification of the reaction but lack any structural information. Several compounds with multiple reaction sites were successfully tested with the proposed NMR method. Otherwise, these compounds have proven to be a challenge to identify and classify using existing alternative methods.
Co-reporter:Mubashir Masoodi, Zulfiqar Ali, Shuang Liang, Hongquan Yin, Wei Wang, Ikhlas A. Khan
Phytochemistry Letters 2015 13() pp: 275-279
Publication Date(Web):
DOI:10.1016/j.phytol.2015.07.005
Co-reporter:Iffat Parveen;Mei Wang;Jianping Zhao;Amar G. Chittiboyina
Plant Molecular Biology 2015 Volume 89( Issue 4-5) pp:451-462
Publication Date(Web):2015 November
DOI:10.1007/s11103-015-0381-3
Ginkgo biloba is one of the oldest living tree species and has been extensively investigated as a source of bioactive natural compounds, including bioactive flavonoids, diterpene lactones, terpenoids and polysaccharides which accumulate in foliar tissues. Despite this chemical diversity, relatively few enzymes associated with any biosynthetic pathway from ginkgo have been characterized to date. In the present work, predicted transcripts potentially encoding enzymes associated with the biosynthesis of diterpenoid and terpenoid compounds, including putative terpene synthases, were first identified by mining publicly-available G. biloba RNA-seq data sets. Recombinant enzyme studies with two of the TPS-like sequences led to the identification of GbTPS1 and GbTPS2, encoding farnesol and bisabolene synthases, respectively. Additionally, the phylogenetic analysis revealed the two terpene synthase genes as primitive genes that might have evolved from an ancestral diterpene synthase.
Co-reporter:Mei Wang, Bharathi Avula, Yan-Hong Wang, Jianping Zhao, Cristina Avonto, Jon F. Parcher, Vijayasankar Raman, Jerry A. Zweigenbaum, Philip L. Wylie, Ikhlas A. Khan
Food Chemistry 2014 Volume 152() pp:391-398
Publication Date(Web):1 June 2014
DOI:10.1016/j.foodchem.2013.11.118
•Three types of chamomile flowers, commercial products and oils were analysed.•A sample class prediction (SCP) model was constructed based on chemometrics.•Commercial products and oils containing chamomile were predicted by the SCP model.•Identification of markers correlated with different chamomiles was explored.As part of an ongoing research program on authentication, safety and biological evaluation of phytochemicals and dietary supplements, an in-depth chemical investigation of different types of chamomile was performed. A collection of chamomile samples including authenticated plants, commercial products and essential oils was analysed by GC/MS. Twenty-seven authenticated plant samples representing three types of chamomile, viz. German chamomile, Roman chamomile and Juhua were analysed. This set of data was employed to construct a sample class prediction (SCP) model based on stepwise reduction of data dimensionality followed by principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The model was cross-validated with samples including authenticated plants and commercial products. The model demonstrated 100.0% accuracy for both recognition and prediction abilities. In addition, 35 commercial products and 11 essential oils purported to contain chamomile were subsequently predicted by the validated PLS-DA model. Furthermore, tentative identification of the marker compounds correlated with different types of chamomile was explored.
Co-reporter:Jianping Zhao ; Shabana I. Khan ; Mei Wang ; Yelkaira Vasquez ; Min Hye Yang ; Bharathi Avula ; Yan-Hong Wang ; Cristina Avonto ; Troy J. Smillie ;Ikhlas A. Khan
Journal of Natural Products 2014 Volume 77(Issue 3) pp:509-515
Publication Date(Web):January 28, 2014
DOI:10.1021/np400780n
Six new octulosonic acid derivatives (1–6) were isolated from the flower heads of Roman chamomile (Chamaemelum nobile). Their structures were elucidated by means of spectroscopic interpretation. The biological activity of the isolated compounds was evaluated toward multiple targets related to inflammation and metabolic disorder such as NAG-1, NF-κB, iNOS, ROS, PPARα, PPARγ, and LXR. Similar to the action of NSAIDs, all the six compounds (1–6) increased NAG-1 activity 2–3-fold. They also decreased cellular oxidative stress by inhibiting ROS generation. Compounds 3, 5, and 6 activated PPARγ 1.6–2.1-fold, while PPARα was activated 1.4-fold by compounds 5 and 6 only. None of the compounds showed significant activity against iNOS or NF-κB. This is the first report of biological activity of octulosonic acid derivatives toward multiple pathways related to inflammation and metabolic disorder. The reported anti-inflammatory, hypoglycemic, antiedemic, and antioxidant activities of Roman chamomile could be partly explained as due to the presence of these constituents.
Co-reporter:Mei Wang, Jianping Zhao, Bharathi Avula, Yan-Hong Wang, Cristina Avonto, Amar G. Chittiboyina, Philip L. Wylie, Jon F. Parcher, and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2014 Volume 62(Issue 50) pp:12103-12111
Publication Date(Web):November 10, 2014
DOI:10.1021/jf503980f
A high-resolution gas chromatography/mass spectrometry (GC/MS) with selected ion monitor method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts, and commercial products was developed and validated. The method involved sample extraction with (1:1) methanol and 10% formic acid, liquid–liquid extraction with n-hexane, and derivatization with trimethylsulfonium hydroxide (TMSH). Separation of two saturated (C13:0 and C15:0) and six unsaturated ginkgolic acid methyl esters with different positional double bonds (C15:1 Δ8 and Δ10, C17:1 Δ8, Δ10, and Δ12, and C17:2) was achieved on a very polar (88% cyanopropyl) aryl-polysiloxane HP-88 capillary GC column. The double bond positions in the GAs were determined by ozonolysis. The developed GC/MS method was validated according to ICH guidelines, and the quantitation results were verified by comparison with a standard high-performance liquid chromatography method. Nineteen G. biloba authenticated and commercial plant samples and 21 dietary supplements purported to contain G. biloba leaf extracts were analyzed. Finally, the presence of the marker compounds, terpene trilactones and flavonol glycosides for Ginkgo biloba in the dietary supplements was determined by UHPLC/MS and used to confirm the presence of G. biloba leaf extracts in all of the botanical dietary supplements.
Co-reporter:Mei Wang;Emily J. Carrell;Zulfiqar Ali;Bharathi Avula;Cristina Avonto;Jon F. Parcher;Ikhlas A. Khan
Journal of Separation Science 2014 Volume 37( Issue 12) pp:1411-1418
Publication Date(Web):
DOI:10.1002/jssc.201301389
Leaves of the Southeast Asian plant Mitragyna speciosa are used to suppress pain and mitigate opioid withdrawal syndromes. The potential threat of abuse and ready availability of this uncontrolled psychoactive plant have led to the need for improved analytical techniques for the detection of the major active components, mitragynine and 7-hydroxymitragynine. Three independent chromatographic methods coupled to two detection systems, GC with MS, supercritical fluid chromatography with diode array detection, and HPLC with MS and diode array detection, were compared for the analysis of mitragynine and other indole and oxindole alkaloids in M. speciosa plants. The indole alkaloids included two sets of diastereoisomers: (i) paynantheine and 3-isopaynantheine and (ii) mitragynine, speciogynine, and speciociliatine. Two oxindole alkaloid diastereoisomers, corynoxine and corynoxine B, were also studied. The HPLC and supercritical fluid chromatography methods successfully resolved the major components with slightly different elution orders. The GC method was less satisfactory because it was unable to resolve mitragynine and speciociliatine. This separation was difficult by GC with a liquid stationary phase because these diastereoisomers differ only in the orientation of an interior hydrogen atom. The observed lack of resolution of the indole alkaloid diastereoisomers coupled with the likeness of the mass and tandem mass spectra, calls into question proposed GC methods for the analysis of mitragynine based on solely GC with MS separation and identification.
Co-reporter:Satyanarayanaraju Sagi;Bharathi Avula;Yan-Hong Wang;Jianping Zhao;Ikhlas A. Khan
Journal of Separation Science 2014 Volume 37( Issue 19) pp:2797-2804
Publication Date(Web):
DOI:10.1002/jssc.201400646
A simple and rapid high-performance thin-layer chromatographic method was developed for the separation and determination of six flavonoids (rutin, luteolin-7-O-β-glucoside, chamaemeloside, apigenin-7-O-β-glucoside, luteolin, apigenin) and one coumarin, umbelliferone from chamomile plant samples and dietary supplements. The separation was achieved on amino silica stationary phase using dichloromethane/acetonitrile/ethyl formate/glacial acetic acid/formic acid (11:2.5:3:1.25:1.25 v/v/v/v/v) as the mobile phase. The quantitation of each compound was carried out using densitometric reflection/absorption mode at their respective absorbance maxima after postchromatographic derivatization using natural products reagent (1% w/v methanolic solution of diphenylboric acid-β-ethylamino ester). The method was validated for specificity, limits of detection and quantification, precision (intra- and interday) and accuracy. The limits of detection and quantification were found to be in the range from 6–18 and 16–55 ng/band for six flavonoids and one coumarin, respectively. The intra- and interday precision was found to be <5% RSD and recovery of all the compounds was >90%. The data acquired from high-performance thin-layer chromatography was processed by principal component analysis using XLSTAT statistical software. Application of principal component analysis and agglomerative hierarchial clustering was successfully able to differentiate two chamomiles (German and Roman) and Chrysanthemum.
Co-reporter:Bharathi Avula, Yan-Hong Wang, Mei Wang, Cristina Avonto, Jianping Zhao, Troy J. Smillie, Diego Rua, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2014 Volume 88() pp:278-288
Publication Date(Web):25 January 2014
DOI:10.1016/j.jpba.2013.08.037
•This study was done to differentiate the Roman from German Chamomiles and Chrysanthemum morifolium (Chinese Chamomile).•Fast UHPLC-UV method for determination of phenolic compounds from flower heads of Chamomiles and Chrysanthemum species.•PLS-DA was used to discriminate chamomiles and Chrysanthemum samples according to their different chemical entities.•LC-mass spectrometry used for confirmation of phenolic compounds in samples of chamomiles.•Commercial samples analyzed showed varied amounts and useful analytical tool for routine analysis to ensure quality control.A new rapid UHPLC-UV-QTOF/MS method has been developed for the simultaneous analysis of nine phenolic compounds [(Z)-2-β-d-glucopyranosyloxy-4-methoxycinnamic acid (cis-GMCA), chlorogenic acid, (E)-2-β-d-glucopyranosyloxy-4-methoxycinnamic acid (trans-GMCA), quercetagetin-7-O-β-d-glucopyranoside, luteolin-7-O-β-d-glucoside, apigenin-7-O-β-d-glucoside, chamaemeloside, apigenin 7-O-(6″-O-acetyl-β-d-glucopyranoside), apigenin] and one polyacetylene (tonghaosu) from the flower heads of Chamomile/Chrysanthemum samples. The chromatographic separation was achieved using a reversed phase C18 column with a mobile phase of water and acetonitrile, both containing 0.05% formic acid. The ten compounds were completely separated within 15 min at a flow rate of 0.25 mL/min with a 2 μL injection volume. The different chemo-types of Chamomiles/Chrysanthemum displayed variations in the presence of chemical constituents. German Chamomile samples confirmed the presence of cis-GMCA, trans-GMCA, apigenin-7-O-β-d-glucoside and tonghaosu as major constituents whereas Roman chamomile samples confirmed the presence of chamamaeloside and apigenin as major compounds. The Chrysanthemum morifolium samples showed the presence of luteolin-7-O-β-d-glucose as the major compound. The method was applied for the analysis of various commercial products including capsules, tea bags, body and hair care products. LC-mass spectrometry with electrospray ionization (ESI) interface method is described for the evaluation of ten compounds in plant samples and commercial products. This method involved the detection of [M+Na]+ and [M+H]+ ions in the positive mode. Partial least squares discriminant analysis (PLS-DA) was used to visualize commercial samples quality and may be of value for discriminating between chamomile types and Chrysanthemum with regards to the relative content of individual constituents. The results indicated that the method is suitable as a quality control test for various Chamomile/Chrysanthemum samples and market products.Chamomile/Chrysanthemum authenticated and commercial samples: scatterplot of first and second principal component obtained by PLS-DA on the basis of UHPLC-QTOF–MS peak area data.
Co-reporter:Zulfiqar Ali, Hatice Demiray, Ikhlas A. Khan
Tetrahedron Letters 2014 Volume 55(Issue 2) pp:369-372
Publication Date(Web):8 January 2014
DOI:10.1016/j.tetlet.2013.11.031
A new indole alkaloid, 7β-hydroxy-7H-mitraciliatine (1) and a new oxindole alkaloid, isospeciofoleine (2) together with nine known alkaloids were isolated from Mitragyna speciosa and characterized by NMR, CD, and MS spectroscopic data analyses. The 1H and 13C NMR spectroscopic data of isospeciofoline (3), isorotundifoline (4), paynantheine (5), and 3-isopaynantheine (6) were also reported for the first time.
Co-reporter:Vijayasankar Raman;Ahmed M. Galal;Bharathi Avula
Journal of Natural Medicines 2014 Volume 68( Issue 4) pp:686-698
Publication Date(Web):2014 October
DOI:10.1007/s11418-014-0849-5
The edible tubers from different species of Dioscorea are a major source of food and nutrition for millions of people. Some of the species are medicinally important but others are toxic. The genus consists of about 630 species of almost wholly dioecious plants, many of them poorly characterized. The taxonomy of Dioscorea is confusing and identification of the species is generally problematic. There are no adequate anatomical studies available for most of the species. This study is aimed to fill this gap and provides a detailed investigation of the anatomy and micro-morphology of the rhizomes and tubers of five different species of Dioscorea, namely D. balcanica, D. bulbifera, D. polystachya, D. rotundata and D. villosa. The primary features that can help in distinguishing the species include the nature of periderm, presence or absence of pericyclic sclereids, lignification in the phloem, types of calcium oxalate crystals and features of starch grains. The descriptions are supported with images of bright-field and scanning electron microscopy for better understanding of these species. The diagnostic key of anatomical features included in this paper can help distinguish the investigated species unambiguously. Additionally, HPTLC analyses of authentic and commercial samples of the five species are described.
Co-reporter:Bharathi Avula, Pieter A. Cohen, Yan-Hong Wang, Satyanarayanaraju Sagi, Wei Feng, Mei Wang, Jerry Zweigenbaum, Ma Shuangcheng, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2014 100() pp: 243-253
Publication Date(Web):
DOI:10.1016/j.jpba.2014.07.039
Co-reporter:Vijayasankar Raman;Harry T. Horner;Ikhlas A. Khan
Journal of Plant Research 2014 Volume 127( Issue 6) pp:721-730
Publication Date(Web):2014 November
DOI:10.1007/s10265-014-0654-y
Calcium oxalate crystals in higher plants occur in five major forms namely raphides, styloids, prisms, druses and crystal sand. The form, shape and occurrence of calcium oxalate crystals in plants are species- and tissue-specific, hence the presence or absence of a particular type of crystal can be used as a taxonomic character. So far, four different types of needle-like raphide crystals have been reported in plants. The present work describes two new and unusual forms of raphide crystals from the tubers of Dioscorea polystachya—six-sided needles with pointed ends (Type V) and four-sided needles with beveled ends (Type VI). Both of these new types of needles are distinct from the other four types by each having a surrounding membrane that envelopes a bundle of 10–20 closely packed thin crystalline sheets. The previously known four types of needles have solid or homogenous crystalline material, surrounded by a membrane or lamellate sheath called a crystal chamber. Only the Type VI crystals have beveled ends and the needles of the other five types have pointed ends.
Co-reporter:Cristina Avonto ; Mei Wang ; Amar G. Chittiboyina ; Bharathi Avula ; Jianping Zhao ;Ikhlas A. Khan
Journal of Natural Products 2013 Volume 76(Issue 10) pp:1848-1853
Publication Date(Web):September 26, 2013
DOI:10.1021/np4003349
German chamomile (Matricaria chamomilla) is one of the most popular medicinal plants used in Western herbal medicine. Among the various phytochemicals present in the essential oil of the flowers of German chamomile, bisabolol and its oxidized metabolites are considered as marker compounds for distinguishing different chemotypes. These compounds are influential in mediating the aroma of the essential oil of M. chamomilla and contribute to the therapeutic properties (anti-inflammatory, antibacterial, insecticidal, and antiulcer) of this species. In order to find other possible bisabolol derivatives as marker compounds for authentication of German chamomile in botanical and commercial products, an in-depth investigation using a GC-assisted fractionation procedure was performed on nonpolar fractions. As a result of this approach, three new hydroxylated derivatives of bisabolol oxides A and B (1–3) have been isolated from M. chamomilla. Plausible biogenetic pathways are presented.
Co-reporter:Nurhayat Tabanca, Mei Wang, Cristina Avonto, Amar G. Chittiboyina, Jon F. Parcher, John F. Carroll, Matthew Kramer, and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 17) pp:4101-4107
Publication Date(Web):March 25, 2013
DOI:10.1021/jf400246a
The evaluation of 10 essential oils of geranium, Pelargonium graveolens (Geraniaceae), were all shown to have repellent activity against nymphs of the medically important lone star tick, Amblyomma americanum (L.). The biological tests were carried out using a vertical filter paper bioassay, where ticks must cross an area of the paper treated with repellent to approach host stimuli. One of the essential oil samples that repelled >90% of the ticks at 0.103 mg/cm2 was selected for further fractionation studies. The sesquiterpene alcohol, (−)-10-epi-γ-eudesmol, was isolated and identified by spectral methods. (−)-10-epi-γ-Eudesmol at 0.103 and 0.052 mg of compound/cm2 of filter paper repelled 90 and 73.3% of the ticks, respectively. (−)-10-epi-γ-Eudesmol exhibited similar repellency to the reference standard N,N-diethyl-meta-toluamide (DEET) at concentrations of ≥0.052 mg of compound/cm2 of filter paper, with (−)-10-epi-γ-eudesmol losing much of its repellency at 0.026 mg of compound/cm2 and DEET at 0.013 mg of compound/cm2. Isomenthone and linalool did not repel ticks at the concentrations tested. Most repellents are marketed with much higher concentrations of active ingredient than the concentrations of the natural repellents tested herein; therefore, effective compounds, such as (−)-10-epi-γ-eudesmol, found in geranium oil, have the potential for commercial development.
Co-reporter:Yan-Hong Wang, Bharathi Avula, N. P. Dhammika Nanayakkara, Jianping Zhao, and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 18) pp:4470-4476
Publication Date(Web):April 12, 2013
DOI:10.1021/jf4005862
Coumarin as an additive or as a constituent of tonka beans or tonka extracts is banned from food in the United States due to its potentially adverse side effects. However, coumarin in food from other natural ingredients is not regulated. “True Cinnamon” refers to the dried inner bark of Cinnamomum verum. Other cinnamon species, C. cassia, C. loureiroi, and C. burmannii, commonly known as cassia, are also sold in the U.S. as cinnamon. In the present study, coumarin and other marker compounds were analyzed in authenticated cinnamon bark samples as well as locally bought cinnamon samples, cinnamon-flavored foods, and cinnamon-based food supplements using a validated UPLC-UV/MS method. The experimental results indicated that C. verum bark contained only traces of coumarin, whereas barks from all three cassia species, especially C. loureiroi and C. burmannii, contained substantial amounts of coumarin. These species could be potential sources of coumarin in cinnamon-flavored food in the U.S. Coumarin was detected in all locally bought cinnamon, cinnamon-flavored foods, and cinnamon food supplements. Their chemical profiles indicated that the cinnamon samples and the cinnamon in food supplements and flavored foods were probably Indonesian cassia, C. burmannii.
Co-reporter:Nurhayat Tabanca, Cristina Avonto, Mei Wang, Jon F. Parcher, Abbas Ali, Betul Demirci, Vijayasankar Raman, and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 50) pp:12283-12291
Publication Date(Web):November 22, 2013
DOI:10.1021/jf4052682
Umbellularia californica (California bay laurel) and Laurus nobilis (Mediterranean bay laurel) leaves may be mistaken or used as a substitute on the market due to their morphological similarity. In this study, a comparison of anatomical and chemical features and biological activity of both plants is presented. L. nobilis essential oil biting deterrent and larvicidal activity were negligible. On the other hand, U. californica leaf oil showed biting deterrent activity against Aedes aegypti. The identified active repellents was thymol, along with (−)-umbellulone, 1,8-cineole, and (−)-α-terpineol. U. californica essential oil also demonstrated good larvicidal activity against 1-day-old Ae. aegypti larvae with a LD50 value of 52.6 ppm. Thymol (LD50 = 17.6 ppm), p-cymene, (−)-umbellulone, and methyleugenol were the primary larvicidal in this oil. Umbellulone was found as the principal compound (37%) of U. californica essential oil, but was not present in L. nobilis essential oil. Umbellulone mosquito activity is here reported for the first time.
Co-reporter:Zulfiqar Ali, Troy J. Smillie, Ikhlas A. Khan
Carbohydrate Research 2013 370() pp: 86-91
Publication Date(Web):5 April 2013
DOI:10.1016/j.carres.2012.12.022
Phytochemical investigation of the MeOH extract of Dioscorea villosa rhizomes resulted in the isolation of two new bidesmosidic cholestane steroid glycosides, dioscoreavillosides A and B (1 and 2). In addition, the extract yielded 12 previously known furostan and spirostan steroid glycosides (3–14), along with diosgenin (15). Compounds 3–7, 9, 14, and 15 were isolated for the first time from D. villosa. The structures of the isolated compounds were determined using spectroscopic and chemical methods including 1D and 2D NMR. The antimicrobial action of most of these compounds was tested against five fungal and five bacterial strains.Graphical abstractHighlight► Phytochemical investigation of the MeOH extract of Dioscorea villosa rhizomes. ► Fifteen compounds including two new bidesmosidic cholestane steroid glycosides. ► Structure elucidation by spectroscopic and chemical methods. ► Antimicrobial action of the isolated compounds.
Co-reporter:Ahmed M. Galal;Vijayasankar Raman;Bharathi Avula
Journal of Natural Medicines 2013 Volume 67( Issue 3) pp:554-561
Publication Date(Web):2013 July
DOI:10.1007/s11418-012-0717-0
This paper presents a comparative study of anatomy of leaves, stems and roots of three species of Plumbago, namely P. auriculata Lam., P. indica L. and P. zeylanica L. by light microscopy. The paper also provides qualitative and quantitative analysis of the naphthoquinone, plumbagin—a major constituent present in these species—using UPLC-UV. Microscopic examinations revealed the presence of distinctive differences in the anatomical features of the leaf, stem and root of the three species, and these can thus be used for identification and authentication of these species. UPLC-UV analysis showed the highest concentration of plumbagin in the roots of P. zeylanica (1.62 % w/w) followed by the roots of P. indica (0.97 % w/w) and then P. auriculata (0.33–0.53 % w/w). In contrast, plumbagin was not detected in the stems and leaves of P. indica and in the leaves of P. auriculata, whereas very low concentrations (<0.02 % w/w) of plumbagin were detected in the stems and leaves of P. zeylanica and in the stems of P. auriculata. HPTLC fingerprints of the leaf and root of the three species exhibited distinguishable profiles, while those of the stems were undifferentiated.
Co-reporter:Tao Yuan, Yuanqing Ding, Chunpeng Wan, Liya Li, Jialin Xu, Ke Liu, Angela Slitt, Daneel Ferreira, Ikhlas A. Khan, and Navindra P. Seeram
Organic Letters 2012 Volume 14(Issue 20) pp:5358-5361
Publication Date(Web):October 10, 2012
DOI:10.1021/ol302548c
Two new ellagitannins containing a rare 3-oxo-1,3,3a,8b-tetrahydrofuro[3,4-b]benzofuran moiety, namely punicatannins A (1) and B (2), were isolated from pomegranate (Punica granatum) flowers. Their structures with absolute configuration were determined by detailed analysis of spectroscopic data, electronic circular dichroism (ECD) calculation, and chemical hydrolysis. A plausible biogenetic route involving a key enzymatic 1,4-Michael addition is proposed. Punicatannin A showed potent inhibition of α-glucosidase and lipogenic gene expression.
Co-reporter:Ikhlas A. Khan and Troy Smillie
Journal of Natural Products 2012 Volume 75(Issue 9) pp:1665-1673
Publication Date(Web):August 31, 2012
DOI:10.1021/np300434j
Natural products have provided a basis for health care and medicine to humankind since the beginning of civilization. According to the World Health Organization (WHO), approximately 80% of the world population still relies on herbal medicines for health-related benefits. In the United States, over 42% of the population claimed to have used botanical dietary supplements to either augment their current diet or to “treat” or “prevent” a particular health-related issue. This has led to the development of a burgeoning industry in the U.S. ($4.8 billion per year in 2008) to supply dietary supplements to the consumer. However, many commercial botanical products are poorly defined scientifically, and the consumer must take it on faith that the supplement they are ingesting is an accurate representation of what is listed on the label, and that it contains the purportedly “active” constituents they seek. Many dietary supplement manufacturers, academic research groups, and governmental organizations are progressively attempting to construct a better scientific understanding of natural products, herbals, and botanical dietary supplements that have co-evolved with Western-style pharmaceutical medicines. However, a deficiency of knowledge is still evident, and this issue needs to be addressed in order to achieve a significant level of safety, efficacy, and quality for commercial natural products. The authors contend that a “quality by design” approach for botanical dietary supplements should be implemented in order to ensure the safety and integrity of these products. Initiating this approach with the authentication of the starting plant material is an essential first step, and in this review several techniques that can aid in this endeavor are outlined.
Co-reporter:Jing Li, Yan-Hong Wang, Troy J. Smillie, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2012 Volume 63() pp:120-127
Publication Date(Web):7 April 2012
DOI:10.1016/j.jpba.2012.01.027
Co-reporter:Li Chen, Tianjiao Zhu, Yuanqing Ding, Ikhlas A. Khan, Qianqun Gu, Dehai Li
Tetrahedron Letters 2012 Volume 53(Issue 3) pp:325-328
Publication Date(Web):18 January 2012
DOI:10.1016/j.tetlet.2011.11.038
A novel sorbicillinoid named sorbiterrin A (1), possessing an unprecedented skeleton was isolated from a marine sediment derived fungus Penicillium terrestre. The structure including absolute stereochemistries was elucidated by analysis of NMR, MS data and TDDFT CD calculations. Sorbiterrin A showed moderate acetylcholinesterase (AChE) inhibitory effect with IC50 25 μg/mL.
Co-reporter:Mei Wang, Bharathi Avula, Yan-Hong Wang, Jon F. Parcher, Ikhlas A. Khan
Journal of Chromatography A 2012 1220() pp: 75-81
Publication Date(Web):
DOI:10.1016/j.chroma.2011.11.051
Co-reporter:Bharathi Avula, Yan-Hong Wang, Nurdan S. Duzgoren-Aydin, Ikhlas A. Khan
Food Chemistry 2011 Volume 127(Issue 1) pp:54-62
Publication Date(Web):1 July 2011
DOI:10.1016/j.foodchem.2010.12.083
Thirty five different commercially available multivitamin/mineral (MVM) dietary supplements in tablet, capsule, liquid or powder form for children, women, men, young and adult consumption were analysed by collision/reaction cell ICP-MS for their inorganic elemental compositions including Na, Mg, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, Hg, and Pb. Samples were digested with concentrated nitric and hydrochloric acid (8:2) using a closed vessel microwave system. The validity of the applied method was assessed by the analysis of standard reference materials (SRM 3280, SRM 1566b) and of spiked samples. Special emphasis was given to the percentage deviation of calculated daily intake of each analysed element from their corresponding label claim. Additionally, for toxic elements calculated daily intake values are compared with those of the regulatory guideline values (e.g., recommended dietary allowance). The results revealed that all analysed products have calculated daily intake of As, Cd, Pb and Hg concentrations lower than those of the regulatory limits. The percentage differences between the calculated and claimed daily intake values varied moderately (20%) to significantly (>30%) for the potentially toxic elements, especially Cr, Se, Mn, and Zn. Furthermore, it is not uncommon for the same product to have high, as well as low, elemental compositions compared to their corresponding claimed values.Research highlights► Microwave assisted CRC ICP-MS used for analysis of multi-element determination. ► The validity of the applied method was assessed by the analysis of standard reference materials. ► Thirty five popular multivitamin/mineral dietary supplements were analysed and their composition levels varied. ► Daily intake of As, Cd, Pb and Hg concentrations were lower than those of the regulatory limits in all 35 products. ► The percentage deviation from the label claim is element specific.
Co-reporter:Wimal Herath, Ikhlas Ahmad Khan
Bioorganic & Medicinal Chemistry Letters 2011 21(19) pp: 5784-5786
Publication Date(Web):
DOI:10.1016/j.bmcl.2011.08.004
Co-reporter:Zulfiqar Ali, Ikhlas A. Khan
Phytochemistry 2011 Volume 72(Issue 16) pp:2075-2080
Publication Date(Web):November 2011
DOI:10.1016/j.phytochem.2011.06.014
Recently, there is a remarkable boom in the sales of Labisia pumila (Kacip Fatimah) in the Malaysian market, as an extract of the plant is used to gain energy and libido as well as to treat many other ailments. A chemical analysis of its roots was undertaken and three metabolites, demethylbelamcandaquinone B (1), fatimahol (2), and dexyloprimulanin (3) together with 21 known compounds including epoxyoleanane glycosides, alkenated phenolics, cerebroside, glycerogalactolipids, and lipids were isolated and identified. Structure elucidation was achieved by spectroscopic and chemical studies. The MeOH extract of KF and compounds 12 and 13 exhibited moderate in vitro antibacterial activity.Graphical abstractDemethylbelamcandaquinone B, fatimahol, and dexyloprimulanin were isolated and identified from the MeOH extract of roots of Labisia pumila.Highlights► Recently, there is a remarkable boom in the sales of Labisia pumila (Kacip Fatimah) in the Malaysian market. ► The chemistry of Labisia pumila was investigated, with 24 compounds (3 previously unknown) isolated and identified. ► In vitro antimicrobial activity of the extract and pure compounds.
Co-reporter:Bharathi Avula, Yan-Hong Wang, Chidananda Swamy Rumalla, Zulfiqar Ali, Troy J. Smillie, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2011 56(5) pp: 895-903
Publication Date(Web):
DOI:10.1016/j.jpba.2011.07.028
Co-reporter:Bharathi Avula, Yan-Hong Wang, Troy J. Smillie, Nurdan S. Duzgoren-Aydin and Ikhlas A. Khan
Journal of Agricultural and Food Chemistry 2010 Volume 58(Issue 16) pp:8887-8894
Publication Date(Web):August 3, 2010
DOI:10.1021/jf101598g
A method was developed and validated for the analysis of 21 elements in various botanicals and dietary supplements using ICP-MS. Closed-vessel microwave digestion of botanicals and dietary products was assisted by various different procedures. The samples digested with concentrated nitric and hydrochloric acid (8:2) revealed the best recoveries (91−106%) using the reference certified materials (SRM 3280, SRM 1566b). The method was validated for linearity, precision, accuracy, LOD, and LOQ. The LOD was found to be in the range from 0.005 to 1.09 ng/mL with the exception of potassium. Eleven botanicals and 21 dietary supplements were analyzed. Among the analyzed elements, K was the most abundant followed by Na, Mg, Al, Ca, Mn, and Fe, whereas V, Cr, Co, Ni, Se, Cd, Hg, and Pb were present in low concentrations in most of the samples. The results showed that the ICP-MS method is a simple, fast, and reliable for the multielement determination in dietary supplements and botanicals.
Co-reporter:Wei Wang;Zulfiqar Ali;Xing-Cong Li;IkhlasA. Khan
Helvetica Chimica Acta 2010 Volume 93( Issue 1) pp:
Publication Date(Web):
DOI:10.1002/hlca.200900211
Abstract
Six new neolignans, casearialignans A–F (1–6, resp.) and one known lignan syringaresinol-β-D-glucoside were isolated from the leaves of Casearia sylvestris. Their structures were determined on the basis of 1D- and 2D-NMR, and HR-ESI-MS analyses. The relative and absolute configurations were determined by the value of the coupling constants and CD spectral analysis, respectively.
Co-reporter:Amany K. Ibrahim, Mohamed M. Radwan, Safwat A. Ahmed, Desmond Slade, Samir A. Ross, Mahmoud A. ElSohly, Ikhlas A. Khan
Phytochemistry 2010 Volume 71(8–9) pp:1014-1019
Publication Date(Web):June 2010
DOI:10.1016/j.phytochem.2010.02.011
Microbial metabolism of cannflavin A (1) and B (2), two biologically active flavonoids isolated from Cannabis sativa L., produced five metabolites (3–7). Incubation of 1 and 2 with Mucor ramannianus (ATCC 9628) and Beauveria bassiana (ATCC 13144), respectively, yielded 6″S,7″-dihydroxycannflavin A (3), 6″S,7″-dihydroxycannflavin A 7-sulfate (4) and 6″S,7″-dihydroxycannflavin A 4′-O-α-l-rhamnopyranoside (5), and cannflavin B 7-O-β-d-4‴-O-methylglucopyranoside (6) and cannflavin B 7-sulfate (7), respectively. All compounds were evaluated for antimicrobial and antiprotozoal activity.Microbial metabolism of cannflavin A (1) and B (2) with Mucor ramannianus and Beauveria bassiana, respectively, produced five metabolites. All compounds were evaluated for antimicrobial and antiprotozoal activity.
Co-reporter:Bharathi Avula, Yan-Hong Wang, Troy J. Smillie, Xiang Fu, Xing Cong Li, Wilfred Mabusela, James Syce, Quinton Johnson, William Folk, Ikhlas A. Khan
Journal of Pharmaceutical and Biomedical Analysis 2010 52(2) pp: 173-180
Publication Date(Web):
DOI:10.1016/j.jpba.2010.01.010
Co-reporter:Jing Li, Yuanqing Ding, Xing-Cong Li, Daneel Ferreira, Shabana Khan, Troy Smillie and Ikhlas A. Khan
Journal of Natural Products 2009 Volume 72(Issue 6) pp:983-987
Publication Date(Web):May 7, 2009
DOI:10.1021/np900068t
Two new dihydropyranocoumarins, scuteflorins A (1) and B (2), together with the known compounds decursin (3), chrysin (4), oroxylin A (5), wogonin (6), 5,7-dihydroxy-8,2′-dimethoxyflavone, dihydrochrysin, dihydrooroxylin A, lupenol, scutellaric acid, pomolic acid, ursolic acid, β-sitosterol, daucosterol, and palmitic acid, were isolated from the aerial parts of Scutellaria lateriflora, commonly used as a dietary supplement. The structures of 1 and 2 were established by means of 1D and 2D NMR spectra as well as HRMS data. The absolute configuration of coumarins 1 and 2 was determined by comparison of experimental and theoretical calculated CD spectra. The cytotoxicity and antioxidant effects of the methanol extract of this plant and some of the constituent flavonoids were evaluated in vitro.
Co-reporter:Wei Wang;Zulfiqar Ali;Xing-Cong Li;IkhlasA. Khan
Helvetica Chimica Acta 2009 Volume 92( Issue 9) pp:1829-1839
Publication Date(Web):
DOI:10.1002/hlca.200900031
Abstract
Five new clerodane diterpene glycosyl derivatives, caseariasides A–E (1–5, resp.) and three new ent-kaurane diterpene glucosides, sylvestrisides C–E (6–8, resp.) were isolated from the leaves of Casearia sylvestris. Their structures were determined on the basis of chemical and spectroscopic analyses.
Co-reporter:Vijai K. Agnihotri, Hala N. ElSohly, Troy J. Smillie, Ikhlas A. Khan, Larry A. Walker
Phytochemistry Letters 2009 Volume 2(Issue 3) pp:103-105
Publication Date(Web):24 August 2009
DOI:10.1016/j.phytol.2009.02.001
Phytochemical investigation of flowering tops of Leonotis leonurus, yielded a new diterpene ester, 1,2,3-trihydroxy-3,7,11,15-tetramethylhexadecan-1-yl-palmitate along with five known metabolites. The structures of all compounds were determined by spectroscopic methods including 1D- and 2D NMR spectroscopy. All the isolated compounds were evaluated for antimalarial, cytotoxicity and for antimicrobial activities. Antimalarial activity for luteolin 7-O-β-d-glucopyranoside (4) (IC50 = 2.2 μg/mL for the D6 clone and 1.8 μg/mL for the W2 clone) was observed. Chloroquine and artemisinin were used as positive controls which showed IC50 of 0.016 and 0.0048 μg/mL for the D6 clone, respectively, and IC50 of 0.14 and 0.0047 μg/mL for the W2 clone, respectively. None of the compounds were cytotoxic to Vero cells up to a concentration of 4.76 μg/mL.1,2,3-Trihydroxy-3,7,11,15-tetramethylhexadecan-1-yl-palmitate (1) along with five known metabolites (2–6) were isolated and characterized by spectroscopic methods including 1D- and 2D NMR spectroscopy.
Co-reporter:Bharathi Avula;Yan-Hong Wang;Troy J. Smillie;Ikhlas A. Khan
Chromatographia 2009 Volume 69( Issue 3-4) pp:307-314
Publication Date(Web):2009 February
DOI:10.1365/s10337-008-0884-z
A simple and specific analytical method for the quantitative determination of shikimic acid from the methanol extract of the fruits of Illicium species and from various plant samples was developed. The LC–UV separation was achieved by reversed-phase chromatography on a C18 column with potassium dihydrogen phosphate and methanol as the mobile phase. In the LC–MS method, the separation was achieved by a C12 column using water and acetonitrile, both containing 0.1% acetic acid as the mobile phase. The methods were successfully used to study the percentage compositions of shikimic acid present in nine species of Illicium and various other plant samples. The detector response was linear with concentrations of shikimic acid in the range from 1.0–500.0 μg mL−1 by LC–UV and 100–1000 ng mL−1 by LC–MS. Mass spectrometry coupled with electrospray ionization interface is described for the identification of shikimic acid in various plant samples. This method involved the use of the [M-H]− ions of shikimic acid at m/z 173.0455 (calculated mass) in the negative ion mode with extractive ion monitoring.
Co-reporter:Yatin J. Shukla, Rahul S. Pawar, Yuanqing Ding, Xing-Cong Li, Daneel Ferreira, Ikhlas A. Khan
Phytochemistry 2009 Volume 70(Issue 5) pp:675-683
Publication Date(Web):March 2009
DOI:10.1016/j.phytochem.2009.02.006
Hoodia gordonii is a ‘weight loss’ herb, which has gained popularity in the western countries as an appetite suppressant dietary supplement. Phytochemical study of its aerial parts led to isolation of seven pregnane glycosides (hoodigosides W–Z, hoodistanalosides A–B). Their structures were elucidated by chemical degradation studies and spectroscopic methods, including 1D and 2D NMR and CD spectroscopic methods.Pregnane glycosides (1, 2, 5–9) were isolated from the aerial parts of Hoodia gordonii. These constituents consisted of five pregnane derivatives namely hoodigogenin A, isoramanone, calogenin, and two unprecedented skeletons, hoodistanal and dehydrohoodistanal as the aglycones.
Co-reporter:Bharathi Avula;Yan-Hong Wang;Troy J. Smillie;Wilfred Mabusela
Chromatographia 2009 Volume 70( Issue 5-6) pp:797-803
Publication Date(Web):2009 September
DOI:10.1365/s10337-009-1237-2
Simple and specific analytical methods for the quantitative determination of sesquiterpenoids from various species of Artemisia plant samples were developed. By LC–UV, LC–ELSD, the separation was achieved by reversed-phase chromatography on a C18 column with water and acetonitrile both containing 0.025% trifluoroacetic acid as the mobile phase. In the LC–MS system, trifluoroacetic acid was replaced by 0.1% formic acid. The wavelength used for quantification of sesquiterpenoids with a diode array detector was 205 nm. The limits of detection by LC–MS was found to be 5, 10, 25, 50, 50 ng mL−1. The limits of detection by LC–UV and LC–ELSD were found to be 5.0, 3.0, 100, 100, 7.5 μg mL−1, by LC–UV and 50, 25, 30, 100 and 75 μg mL−1 by LC–ELSD. LC–mass spectrometry coupled with electrospray ionization (ESI) interface is described for the identification and quantification of sesquiterpenoids in various plant samples. This method involved the use of the [M + H]+ ions of sesquiterpenoids in the positive ion mode with extractive ion monitoring.
Co-reporter:Xiang Fu, Xing-Cong Li, Troy J. Smillie, Paulo Carvalho, Wilfred Mabusela, James Syce, Quinton Johnson, William Folk, Mitchell A. Avery and Ikhlas A. Khan
Journal of Natural Products 2008 Volume 71(Issue 10) pp:1749-1753
Publication Date(Web):September 23, 2008
DOI:10.1021/np800328r
Four new cycloartane glycosides, sutherlandiosides A−D (1−4), were isolated from the South African folk medicine Sutherlandia frutescens and their structures established by spectroscopic methods and X-ray crystallography as 1S,3R,24S,25-tetrahydroxy-7S,10S-epoxy-9,10-seco-9,19-cyclolanost-9(11)-ene 25-O-β-d-glucopyranoside (1), 3R,7S,24S,25-tetrahydroxycycloartan-1-one 25-O-β-d-glucopyranoside (2), 3R,24S,25-trihydroxycycloartane-1,11-dione 25-O-β-d-glucopyranoside (3), and 7S,24S,25-trihydroxycycloart-2-en-1-one 25-O-β-d-glucoyranoside (4). Compound 1 represents the first secocycloartane skeleton possessing a 7,10-oxygen bridge. Compounds 2−4 are also the first examples of naturally occurring cycloartanes with a C-1 ketone functionality. Biosynthetic considerations and chemical evidence suggest that the presence of the C-1 ketone in 2 may facilitate the ring opening of the strained cyclopropane system.
Co-reporter:Zulfiqar Ali, Daneel Ferreira, Paulo Carvalho, Mitchell A. Avery and Ikhlas A. Khan
Journal of Natural Products 2008 Volume 71(Issue 6) pp:1111-1112
Publication Date(Web):May 10, 2008
DOI:10.1021/np800172x
The rare indazole-type alkaloid nigellidine (2) is accompanied by its 4-O-sulfite (4) in the seeds of Nigella sativa. Compound 4 may represent the true natural product leading to nigellidine (2) via hydrolysis of the sulfate functionality during the isolation process. The structure of nigellidine-4-O-sulfite (4) is confirmed by NMR, MS, and X-ray crystallographic data. This is the first report of the natural occurrence of sulfated indazole-type alkaloids.
Co-reporter:Chidana Swamy Rumalla;Bharathi Avula;Yatin J. Shukla;Yan-Hong Wang;Rahul S. Pawar;Troy J. Smillie;Ikhlas A. Khan
Journal of Separation Science 2008 Volume 31( Issue 22) pp:3959-3964
Publication Date(Web):
DOI:10.1002/jssc.200800441
Abstract
A HPTLC method was developed for simple and rapid chemical fingerprint analysis of four Hoodia species, dietary supplements that claim to contain Hoodia gordonii, and plants from genera related to Hoodia. HPTLC was performed on precoated silica 60F254 plates with dichloromethane/methanol/water 75:17:2.2 by volume, as mobile phase. Evaluation of the HPTLC plates was done by using the CAMAG DigiStore2 digital system with winCATS software. The authentication of H. gordonii was achieved by comparing the band colors and Rf values for TLC fingerprints with those of 11 standard compounds including P57. The developed method was successfully applied for the identification of the 11 pregnane glycosides for four different species of Hoodia, 24 related genera and 13 dietary supplements that claim to contain H. gordonii. Different sample matrices were successfully analyzed, providing a wide range of applicability for this method, including gels, capsules, tablets, sprays, teas, snack bars, powders, and juices. The developed method was validated for specificity, stability, repeatability, and robustness. The results of HPTLC method were verified by LC-UV-MS method.
Co-reporter:Vijai K. Agnihotri, Hala N. ElSohly, Shabana I. Khan, Melissa R. Jacob, Vaishali C. Joshi, Troy Smillie, Ikhlas A. Khan, Larry A. Walker
Phytochemistry Letters 2008 Volume 1(Issue 2) pp:89-93
Publication Date(Web):21 August 2008
DOI:10.1016/j.phytol.2008.03.003
From the leaves of Nelumbo nucifera (an aquatic plant), one new compound, 24(R)-ethylcholest-6-ene-5α-ol-3-O-β-d-glucopyranoside (1), along with 11 known metabolites (2–12), were isolated and identified by spectroscopic methods including 1D- and 2D NMR. Antifungal activity for (R)-roemerine (3) (IC50/MIC = 4.5/10 μg/mL against Candida albicans) and antimalarial activity for (R)-roemerine (3) and N-methylasimilobine (5) (IC50 = 0.2 and 4.8 μg/mL for the D6 clone, respectively, and 0.4 and 4.8 μg/mL for the W2 clone, respectively) was observed. None of the compounds were cytotoxic to Vero cells up to a concentration of 23.8 μg/mL. NMR data for 10-eicosanol (7) and 7,11,15-trimethyl-2-hexadecanone (10) are presented for the first time. An analysis of the structure–activity relationship shows that the substituents in position C-1 and C-2 of aporphine alkaloids are crucial for the antimalarial activity.24(R)-Ethylcholest-6-ene-5α-ol-3-O-β-d-glucopyranoside (1), along with 11 known compounds (2–12) including aporphine alkaloids, diterpenes, a steroid glycoside and a flavonoid glycoside were isolated from the leaves of Nelumbo nucifera and evaluated for their antifungal, antimalarial and for cytotoxic activities. Antifungal activity was observed for (R)-roemerine (3) and antimalarial activity for (R)-roemerine (3) and N-methylasimilobine (5). Position C-1 and C-2 of aporphine alkaloids is crucial for antimalarial activity.
Co-reporter:Zengping Gao, Zulfiqar Ali, Jianping Zhao, Liang Qiao, Haimin Lei, Yunru Lu, Ikhlas A. Khan
Phytochemistry Letters 2008 Volume 1(Issue 4) pp:188-190
Publication Date(Web):12 December 2008
DOI:10.1016/j.phytol.2008.09.005
A comprehensive phytochemical investigation of the rhizomes of Dryopteris crassirhizoma Nakai resulted in the isolation and identification of one new trimeric phloroglucinol, trisflavaspidic acid ABB (1) together with 12 known compounds including phloroglucinol, flavan, terpene, phenolic and acyclic analogs. Their structures were established by spectroscopic methods including IR, UV, MS and 1D and 2D NMR.A comprehensive phytochemical investigation of the rhizomes of Dryopteris crassirhizoma resulted in the isolation and identification of 13 compounds including a new trimeric phloroglucinol, trisflavaspidic acid ABB.
Co-reporter:Vijai K. Agnihotri, Hala N. ElSohly, Shabana I. Khan, Troy J. Smillie, Ikhlas A. Khan, Larry A. Walker
Phytochemistry 2008 Volume 69(Issue 10) pp:2061-2066
Publication Date(Web):July 2008
DOI:10.1016/j.phytochem.2008.04.009
As part of an ongoing search for antioxidants from medicinal plants, 20 constituents were isolated from the Nymphaea caerulea flowers, including two 2S,3S,4S-trihydroxypentanoic acid (1), and myricetin 3-O-(3′′-O-acetyl)-α-l-rhamnoside (2), along with the known myricetin 3-O-α-l-rhamnoside (3), myricetin 3-O-β-d-glucoside (4), quercetin 3-O-(3′′-O-acetyl)-α-l-rhamnoside (5), quercetin 3-O-α-l-rhamnoside (6), quercetin 3-O-β-d-glucoside (7), kaempferol 3-O-(3′′-O-acetyl)-α-l-rhamnoside (8), kaempferol 3-O-β-d-glucoside (9), naringenin (10), (S)-naringenin 5-O-β-d-glucoside (11), isosalipurposide (12), β-sitosterol (13), β-sitosterol palmitate (14), 24-methylenecholesterol palmitate (15), 4α-methyl-5α-ergosta-7,24(28)-diene-3β,4β-diol (16), ethyl gallate (17), gallic acid (18), p-coumaric acid (19), and 4-methoxybenzoic acid (20). The structures were determined by spectroscopic means. Compounds were tested for antioxidant activity and nine compounds 2–7, 11, 12 and 18 were considered active with IC50 of 1.16, 4.1, 0.75, 1.7, 1.0, 0.34, 11.0, 1.7 and 0.95 μg/ml, respectively, while 1 was marginally active (IC50 > 31.25 μg/ml). The most promising activity was found in the EtOAc fraction (IC50 0.2 μg/ml). This can be attributed to the synergistic effect of the compounds present in it.Twenty constituents were isolated from the Nymphaea caerulea flowers, including 2S,3S,4S-trihydroxypentanoic acid (1), and myricetin 3-O-(3′′-O-acetyl)-α-l-rhamnoside (2), along with known 18 compounds (3–20). Antioxidant activities of nine compounds 2–7, 11, 12 and 18 were observed with IC50 values of 1.16, 4.1, 0.75, 1.7, 1.0, 0.34, 11.0, 1.7 and 0.95 μg/ml, respectively, while 1 was marginally active (IC50 > 31.25 μg/ml). Promising activity of EtOAc fraction (IC50 0.2 μg/ml) could be attributed to the synergistic effect of the compounds present in it.
Co-reporter:Zengping Gao, Zulfiqar Ali, Ikhlas A. Khan
Phytochemistry 2008 Volume 69(Issue 16) pp:2856-2861
Publication Date(Web):November 2008
DOI:10.1016/j.phytochem.2008.09.002
Four glycerogalactolipids (1–4), together with 11 other previously known homologues were isolated from the fruit of Lycium barbarum. Their structures were elucidated by chemical analyses including regio-selective enzymatic, alkaline and acidic hydrolyses and spectroscopic methods involving GCMS, HRESIMS and 1D and 2D NMR, respectively.Glycerogalactolipids (1–4) were isolated from the fruit of Lycium barbarum.
Co-reporter:Zulfiqar Ali, Ikhlas A. Khan
Phytochemistry 2008 Volume 69(Issue 4) pp:1037-1042
Publication Date(Web):February 2008
DOI:10.1016/j.phytochem.2007.10.011
Blue cohosh, Caulophyllum thalictroides (L.) Michx. (Berberidaceae), is used primarily to cure menstrual disturbances and to ease childbirth. Alkaloids and saponins are considered to be responsible for its pharmacological activity. A detailed phytochemical investigation of blue cohosh resulted in the isolation of 15 compounds belonging to the alkaloids and the triterpene saponins. The structures of two alkaloids, caulophyllumines A (1) and B (2) and a saponin, cauloside H (3) both previously unknown were determined by spectroscopic techniques, including by 1- and 2-D NMR as well as by chemical analysis.Two alkaloids, caulophyllumines A (1) and B (2) and a saponin, cauloside H (3) were isolated from blue cohosh.
Co-reporter:Chidananda Swamy Rumalla, Atul N. Jadhav, Troy Smillie, Frank R. Fronczek, Ikhlas A. Khan
Phytochemistry 2008 Volume 69(Issue 8) pp:1756-1762
Publication Date(Web):May 2008
DOI:10.1016/j.phytochem.2008.01.028
Two alkaloids, 9β,2′-dihydroxy-4′′,5′′-dimethoxy-lythran-12-one or 9β-hydroxyvertine (1) and (2S,4S,10R)-4-(3-hydroxy-4-methoxyphenyl)-quinolizidin-2-acetate (2), as well as seven known alkaloids, lythrine (3), dehydrodecodine (4), lythridine (5), vertine (6), heimidine (7), lyfoline (8) and epi-lyfoline (9), were isolated from Heimia salicifolia. The structures of these compounds were elucidated by extensive spectroscopic techniques. Furthermore, the structures of 2, 3, and 6 were confirmed by X-ray crystallography, including absolute configuration determination of 2 and 6. Compounds 6 and 9 showed moderate antimalarial activity.Two alkaloids, 9β,2′-dihydroxy-4′′,5′′-dimethoxy-lythran-12-one (1) and (2S, 4S, 10R)-4-(3-hydroxy-4-methoxyphenyl)-quinolizidin-2-acetate (2) were isolated from Heimia salicifolia.
Co-reporter:Jamal Mustafa;Shabana I. Khan;Daneel Ferreira;Ikhlas A. Khan
European Journal of Lipid Science and Technology 2007 Volume 109(Issue 6) pp:
Publication Date(Web):31 MAY 2007
DOI:10.1002/ejlt.200600235
An efficient first synthesis of di-, hexa- and octa-esters (octadeca-Z-9,12-dienoates, linoleates) from natural 1,5-bis-(4'-hydroxyphenyl)penta-Z-1,4-diene (Ginkgo biloba L.), (–)-epigallocatechin and (–)-epigallocatechin-3-O-gallate (jasmine tea/green tea), respectively, was developed. Using dicyclohexyl carbodiimide as an activating reagent in the presence of a catalytic amount of 4-dimethylaminopyridine in polyesterification reactions gave di-, hexa- and octa-products (4), (7), and (8), respectively, in quantitative yields. A three-step efficient procedure for the synthesis of 1,5-bis-[4'-O-(octadec-Z-9”,12”-dienoate)phenyl]penta-Z-1,4-diene (4) was also developed. The key step in the synthesis involved a stereo selective Wittig diolefination reaction that produced the penta-Z-1,4-diene system of (4). 1H and 13C NMR and MS techniques confirmed the structures of the esters. The esterified compounds were tested for in vitro anti-tumor activities against four and three human cancer cell lines at NCNPR and at NCI, respectively. They were found inactive as they failed to inhibit 50% growth of these cancer cells.
Co-reporter:Bharathi Avula;Ikhlas A. Khan;Atul N. Jadhav;Rahul S. Pawar
Chemistry & Biodiversity 2007 Volume 4(Issue 9) pp:2225-2230
Publication Date(Web):21 SEP 2007
DOI:10.1002/cbdv.200790180
Seven ecdysteroids, including the three new compounds 1–3, were isolated from Sida rhombifolia L. Their structures and configurations were determined by extensive spectroscopic techniques in combination with chemical derivatization. The four known compounds – ecdysone (4), 20-hydroxyecdysone (5), 2-deoxy-20-hydroxyecdysone-3-O-β-D-glucopyranoside (6), and 20-hydroxyecdysone-3-O-β-D-glucopyranoside (7) – are reported for the first time from this plant.
Co-reporter:Bharathi Avula;Zulfiqar Ali;Ikhlas A. Khan
Chromatographia 2007 Volume 66( Issue 9-10) pp:757-762
Publication Date(Web):2007 November
DOI:10.1365/s10337-007-0384-6
Black cohosh (Actaearecemosa) is a popular botanical used for women’s health. The rhizomes/roots used in black cohosh products are often collected from the wild; a correct identification is therefore crucial. An HPLC-ELSD method has been developed for the analysis of terpenoids in different Actaea species samples. The best results were obtained with a Phenomenex Discovery column using gradient mobile phase of water (0.1% acetic acid), acetonitrile (0.1% acetic acid) and reagent alcohol. Owing to their low UV absorption, the triterpene saponins were detected by evaporative light scattering. Elution was run at a flow rate of 1.0 mL min−1. This paper discusses the use of the chemical fingerprinting technique as a means of identifying A. recemosa from three closely related species, A. pachypoda, A. podocarpa and A. rubra, respectively. This method suggests that the analytical method could be a useful method for quality control and identifying species.
Co-reporter:Zulfiqar Ali, Shabana I. Khan, Frank R. Fronczek, Ikhlas A. Khan
Phytochemistry 2007 Volume 68(Issue 3) pp:373-382
Publication Date(Web):February 2007
DOI:10.1016/j.phytochem.2006.10.021
Seven 9,10-seco-9,19-cyclolanostane arabinosides, named podocarpasides A–G (1–7), were isolated from the roots of Actaea podocarpa DC., a species closely related to black cohosh (a well known dietary supplement). Their structures were determined with the help of spectroscopic data including extensive 2D NMR spectroscopy. The isolates were found inactive, when tested for cytotoxic, estrogenic, and antioxidant activities in cell based assays. They were also tested for anticomplement activity against the classical pathway of complement system and only podocarpaside C (3) inhibited modest complement activity with an IC50 value of 200 μM.Seven 9,10-seco-9,19-cyclolanostane arabinosides, named podocarpasides A–G, were isolated from the roots of Actaea podocarpa DC.
Co-reporter:Erdal Bedir;Nurhayat Tabanca;Desmond Slade;Daneel Ferreira;David E. Wedge;Melissa R. Jacob;Shabana I. Khan;K. Husnu Can Baser;Nese Kirimer;Ikhlas A. Khan
Chemistry & Biodiversity 2006 Volume 3(Issue 7) pp:
Publication Date(Web):26 JUL 2006
DOI:10.1002/cbdv.200690085
Co-reporter:Sara L. Crockett;Ikhlas A. Khan;Brian Schaneberg
Phytochemical Analysis 2005 Volume 16(Issue 6) pp:479-485
Publication Date(Web):5 OCT 2005
DOI:10.1002/pca.875
Botanical extracts of Hypericum perforatum L. (common St. John's Wort) are used in the USA and in Europe as a treatment for mild to moderate depression, although controversy surrounds the identity of the active constituent(s). RP-HPLC with photodiode array detection was used to separate and quantify nine compounds of pharmacological interest in extracts from 74 taxa of Hypericum native to the Old and New World. Chemical profiles of these constituents may be used to distinguish extracts of H. perforatum from those of other species of Hypericum, and to indicate species that may be of interest for further phytochemical investigation. Copyright © 2005 John Wiley & Sons, Ltd.
Co-reporter:Nurhayat Tabanca;Erdal Bedir;Desmond Slade;Daneel Ferreira;David E. Wedge;Melissa R. Jacob;K. Husnu Can Baser;Shabana I. Khan;Nese Kirimer;Ikhlas A. Khan
Chemistry & Biodiversity 2005 Volume 2(Issue 2) pp:221-232
Publication Date(Web):18 FEB 2005
DOI:10.1002/cbdv.200590005
A new ‘phenylpropanoid’, 4-(3-methyloxiran-2-yl)phenyl 2-methylbutanoate (1), a new trinorsesquiterpene, 4-(6-methylbicyclo[4.1.0]hept-2-en-7-yl)butan-2-one (2), and eight known compounds (3–10) were isolated from the essential oils of several Pimpinella species growing in Turkey. The structures of the new compounds were determined by 1D- and 2D-NMR analyses. The absolute configuration of 1 was established via comparison of its optical rotation with that of ‘epoxypseudoisoeugenyl 2-methylbutyrate’ (11), the absolute configuration of which was determined by chemical degradation and an appropriate Mosher ester formation. Direct bioautography revealed antifungal activity of 1 and 11 against Colletotrichum acutatum, C. fragariae, and C. gloesporioides. Subsequent evaluation of antifungal compounds in a 96-well microtiter assay showed that compounds 1 and 11 produced the most-significant growth inhibition in Phomopsis spp., Colletotrichum spp., and Botrytis cinerea. Compounds 1 and 6 displayed antimicrobial activities against Mycobacterium intracellulare, with IC50 values of 2.78 and 1.29 μM, respectively.
Co-reporter:Brian T. Schaneberg;Ikhlas A. Khan;Russell J. Molyneux
Phytochemical Analysis 2004 Volume 15(Issue 1) pp:36-39
Publication Date(Web):23 JAN 2004
DOI:10.1002/pca.715
A reverse-phase high-performance liquid chromatography method utilizing evaporative light scattering detection (ELSD) has been developed for the simultaneous detection of hepatotoxic pyrrolizidine alkaloids with and without chromophores, namely, riddelliine, riddelliine N-oxide, senecionine, senecionine N-oxide, seneciphylline, retrorsine, integerrimine, lasiocarpine and heliotrine. Pyrrolizidine alkaloids were detected in five plant extracts (Senecio spartioides, S. douglasii var. longilobus, S. jacobaea, S. intergerrimus var. exaltatus and Symphytum officinale). The detection of heliotrine (which does not contain a chromophore) was much improved by ELSD compared with photodiode array detection. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:M. Ganzera;H. R. W. Dharmaratne;N. P. D. Nanayakkara;I. A. Khan
Phytochemical Analysis 2003 Volume 14(Issue 1) pp:1-7
Publication Date(Web):16 JAN 2003
DOI:10.1002/pca.666
The roots of Caulophyllum thalictroides, traditionally used for the treatment of menstrual difficulties and as an aid in childbirth, contain saponins, which are considered to be responsible for the uterine stimulant effects, together with teratogenic alkaloids. An HPLC method has been developed which permits the determination of the triterpene saponins in the plant and also the separation of four alkaloids. The best results were obtained with a C-12 stationary phase using ammonium acetate buffer (pH 8.0) and acetonitrile as mobile phase. Owing to their low UV absorbance, the saponins were detected by evaporative light scattering, whereas the alkaloids were monitored by UV at 310 nm. The identities of the compounds were confirmed in an LC-MS experiment. Different plant samples and commercial products have been analysed using the described method, and remarkable qualitative and quantitative variations were revealed. Comparing the daily uptake of total saponins, a difference of greater than 100-fold was observed within the various products; the alkaloid content on the other hand was more uniform. Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:Erdal Bedir, Rangavalli Manyam, Ikhlas A Khan
Phytochemistry 2003 Volume 63(Issue 8) pp:977-983
Publication Date(Web):August 2003
DOI:10.1016/S0031-9422(03)00378-9
A neo-clerodane type diterpenoid, 12(S)-15,16-epoxy-19-hydroxy-neo-cleroda-13(16),14-dien-18,6α:20,12-diolide, and two phenylethanoid glycosides, teucrioside-3⁗-O-methylether and teucrioside-3⁗,4⁗-O-dimethylether were isolated from the aerial parts of Teucrium chamaedrys. Their structures were identified on the basis of extensive NMR spectra, LC-ESIMS analysis, and molecular modeling studies.Three compounds, a neo-clerodane, and two phenylpropanoid glycosides, were isolated from Teucrium chamaedrys L.
Co-reporter:Brian T Schaneberg, Sara Crockett, Erdal Bedir, Ikhlas A Khan
Phytochemistry 2003 Volume 62(Issue 6) pp:911-918
Publication Date(Web):March 2003
DOI:10.1016/S0031-9422(02)00716-1
Ephedra sinica, known as Ma Huang, is one of the oldest medicinal herbs in Traditional Chinese Medicine (TCM). Preparations, namely teas, of E. sinica have been used for over 5000 years as a stimulant and as an antiasthmatic. In the West, extracts of E. sinica, E. intermedia or E. equisetina are most commonly used in dietary supplements as a stimulant and to promote weight loss. More than 50 species of Ephedra are native to both hemispheres, but the detection of ephedrine alkaloids has been limited to species in Eurasia. Currently, methods exist to quantitate the ephedrine alkaloids in extracts of plant material or dietary supplements, but the methods are not able to verify the extract is of an Ephedra species. Reverse phase high performance liquid chromatography with photodiode array detection was applied for the chemical fingerprinting of the Ephedra species. Two regions of comparison were determined in the chromatograms at 320 nm. The series of peaks between 52 and 64 min confirms an Ephedra species is being analyzed. The aforementioned peaks also could distinguish between Ephedra species from Eurasia, North America and South America. Peaks at ca. 57 and 59 min were isolated and determined to be two new compounds, 4-(2-eicosyloxycarbonyl-vinyl)-benzoic acid and 4-(2-docosyloxycarbonyl-vinyl)-benzoic acid respectively. Authentication of ground plant material as Ephedra can be achieved by this chemical fingerprinting method.Ephedra sinica, known as Ma Huang, is one of the oldest medicinal herbs in traditional Chinese medicine. Reverse phase high performance liquid chromatography with photodiode array detection was applied for the chemical fingerprinting of the Ephedra species. Two compounds, 4-(2-eicosyloxycarbonyl-vinyl)-benzoic acid and 4-(2-docosyloxycarbonyl-vinyl)-benzoic acid, were isolated.
Co-reporter:M. Ganzera;J. Zhao;I.A. Khan
Journal of Pharmaceutical Sciences 2002 Volume 91(Issue 3) pp:623-630
Publication Date(Web):30 JAN 2002
DOI:10.1002/jps.10057
The analysis of flavonoids, naphthodianthrones, and the phloroglucinol derivative hyperforin in H. perforatum is described in this article. In a 35-min HPLC run nine major compounds could be identified and baseline separated in the methanolic plant extracts. For an optimum separation the mobile phase consisted of 10 mM ammonium acetate buffer (pH 5.0) and an acetonitrile/methanol mixture; a Synergi MAX-RP 80 Å column (C-12 material) was used as stationary phase. Detection was performed at 270 nm, and the identity of the compounds was confirmed in an LC-MS experiment. Commercial St. John's Wort products were analyzed and qualitative and quantitative results are discussed. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:623–630, 2002
Co-reporter:Mubashir Masoodi, Zulfiqar Ali, Shuang Liang, Hongquan Yin, Wei Wang, Ikhlas A. Khan
Phytochemistry Letters (September 2015) Volume 13() pp:275-279
Publication Date(Web):1 September 2015
DOI:10.1016/j.phytol.2015.07.005
•Phytochemical investigation of the whole plant of Marrubium vulgare is discussed.•Two new labdane diterpenoids were isolated.•Structure elucidation was achieved by means of NMR spectral data and mass.•Antimicrobial activity of isolated diterpenoids is described.Phytochemical investigation of the whole plant of Marrubium vulgare L. (Lamiaceae) resulted in isolation and characterization of two new labdane diterpenoids, 12(S)-hydroxymarrubiin and 3-deoxo-15-methoxyvelutine C and 11 known compounds, marrubiin, peregrinin, thessaline D, marrubinone B, deacetylvitexilactone, verbascoside, leucosceptoside A, martynoside, anisofolin A, terniflorin, and apigenin. Structure elucidation of the isolated compounds was determined by using spectroscopic techniques and HRESIMS. 12(S)-Hydroxymarrubiin, marrubiin, peregrinin, and marrubinone B, exhibited no antimicrobial activity up to 20 μg/mL against ten strains.Download full-size image
Co-reporter:Wei Wang, Zulfiqar Ali, Xing-Cong Li, Troy A. Smillie, De-An Guo, Ikhlas A. Khan
Fitoterapia (October 2009) Volume 80(Issue 7) pp:404-407
Publication Date(Web):1 October 2009
DOI:10.1016/j.fitote.2009.05.013
Two new clerodane diterpenoids 2β-methoxy-cleroda-3,13-dien-18-carboxy-15,16-olide (1) and 15ξ-methoxy-cleroda-3,12-dien-18-carboxy-15,16-olide (2) and one new nitrogen-containing clerodane diterpenoid 15-oxo-echinophyllin A (3), along with six known compounds, namely, echinophyllin A, (−)-patagonic acid, tyrosol, oplopanone, 4-hydroxy-4-methyl-2-[(1R)-1-(1-methylethyl)-4-oxopentyl]-2-cyclohexen-1-one and 1β,6α-dihydroxy-eudesman-4(15)-ene were isolated from the leaves of Casearia sylvestris. Their structures were determined by extensive NMR techniques.Two new clerodane diterpenoids 2β-methoxy-cleroda-3,13-dien-18-carboxy-15,16-olide (1) and 15ξ-methoxy-cleroda-3,12-dien-18-carboxy-15,16-olide (2) and one new nitrogen-containing clerodane diterpenoid 15-oxo-echinophyllin A (3) along with six known compounds were isolated from the leaves of Casearia sylvestris. Their structures were determined by extensive NMR techniques.Download full-size image
Co-reporter:Rahul S. Pawar, Yatin J. Shukla, Ikhlas A. Khan
Steroids (November 2007) Volume 72(Issue 13) pp:881-891
Publication Date(Web):1 November 2007
DOI:10.1016/j.steroids.2007.07.010
Ten new pregnane glycosides (1, 3–11) were isolated from organic extracts of aerial parts of Hoodia gordonii, which is sold as an appetite suppressant herbal supplement. The aglycone was identified as calogenin, based on the spectroscopic data of products obtained upon chemical and enzymatic degradation of parent glycoside. The structures of the glycosides were established by chemical degradation studies and extensive spectroscopic techniques that included one-dimensional and two-dimensional NMR.
Co-reporter:Rahul S. Pawar, Yatin J. Shukla, Shabana I. Khan, Bharathi Avula, Ikhlas A. Khan
Steroids (June 2007) Volume 72(Issues 6–7) pp:524-534
Publication Date(Web):1 June 2007
DOI:10.1016/j.steroids.2007.03.003
Hoodigosides A–K (1–11), eleven new oxypregnane glycosides and a previously reported oxypregnane glycoside P57AS3 were isolated from the aerial parts of Hoodia gordonii. The structures of these 12-O-β-tigloyl isoramanone glycosides were determined on the basis of chemical evidence and extensive spectroscopic methods that include one-dimensional and two-dimensional NMR. Cytotoxicity and antioxidant activities of these compounds were tested in cell based assays where they were found to be inactive.
Co-reporter:Steven L. Neese, Samantha L. Pisani, Daniel R. Doerge, William G. Helferich, Estatira Sepehr, Amar G. Chittiboyina, Sateesh Chandra Kumar Rotte, Troy J. Smillie, Ikhlas A. Khan, Donna L. Korol, Susan L. Schantz
Neurotoxicology and Teratology (January–February 2014) Volume 41() pp:80-88
Publication Date(Web):1 January 2014
DOI:10.1016/j.ntt.2013.12.004
•Botanical estrogens are marketed to midlife women as an aide to healthy aging.•The efficacy of the botanical estrogen S-equol to alter cognition was assessed.•Middle-aged ovariectomized (OVX) rats were treated with S-equol.•Rats were tested on a prefrontal working memory or hippocampal place learning task.•S-equol treatment did not alter learning and memory on these tasks.The use of over-the-counter botanical estrogens containing isolated soy isoflavones, including genistein and daidzein, has become a popular alternative to traditional hormone therapies. Menopausal women use these products as an aide in healthy aging, including for the maintenance of cognitive function. The safety and efficacy of many of these commercial preparations remain unknown. Previous research in our lab found that treatment of ovariectomized (OVX) female Long-Evans rats with genistein impaired working memory in an operant delayed spatial alternation (DSA) task and response learning in a plus-maze, but enhanced place learning assessed in the plus-maze. The present study further examined the effects of isolated isoflavones on working memory and place learning by treating middle-aged (12–13 month old) OVX female Long-Evans rats with S-equol, the exclusive enantiomer produced by metabolism of daidzein in the mammalian gut. S-equol binds selectively to ERβ with an affinity similar to that of genistein but has low transcriptional potency. For DSA testing, S-equol at 1.94, 0.97 mg, or 0 mg (sucrose control) was orally administered to animals daily, 30 min before behavioral testing, and again both 4 and 8 hours after the first treatment. Rats were tested on the DSA task following the first, morning dose. For place learning, rats received 0.97 mg S-equol every 4 hours during the light portion of the cycle beginning 48 hours prior to behavioral testing (total exposure 8.7 mg S-equol). S-equol treatment was largely without effect on the DSA and place learning tasks. This is the first study to test the behavioral effects of isolated S-equol in OVX rodents, and shows that, unlike genistein or estradiol, repeated daily treatment with this isoflavone metabolite does not alter learning and memory processes in middle-aged OVX rats.
Co-reporter:Hoda M. Gebril, Bharathi Avula, Yan-Hong Wang, Ikhlas A. Khan, Mika B. Jekabsons
Neurochemistry International (February 2016) Volume 93() pp:26-39
Publication Date(Web):1 February 2016
DOI:10.1016/j.neuint.2015.12.008
•A model was developed to quantitate neuronal metabolism from 13C2 glucose.•13C randomization in lactate due to hexose phosphate recycling was determined.•Glycolysis and the pentose cycle accounted for 52 and 19%, resp. of glucose used.•Only 16% of glucose was used by mitochondria vs. 46% by lactate dehydrogenase.•This approach yielded extensive flux information from minimal experiments.Glycolysis, mitochondrial substrate oxidation, and the pentose phosphate pathway (PPP) are critical for neuronal bioenergetics and oxidation–reduction homeostasis, but quantitating their fluxes remains challenging, especially when processes such as hexose phosphate (i.e., glucose/fructose-6-phosphate) recycling in the PPP are considered. A hexose phosphate recycling model was developed which exploited the rates of glucose consumption, lactate production, and mitochondrial respiration to infer fluxes through the major glucose consuming pathways of adherent cerebellar granule neurons by replicating [13C]lactate labeling from metabolism of [1,2-13C2]glucose. Flux calculations were predicated on a steady-state system with reactions having known stoichiometries and carbon atom transitions. Non-oxidative PPP activity and consequent hexose phosphate recycling, as well as pyruvate production by cytoplasmic malic enzyme, were optimized by the model and found to account for 28 ± 2% and 7.7 ± 0.2% of hexose phosphate and pyruvate labeling, respectively. From the resulting fluxes, 52 ± 6% of glucose was metabolized by glycolysis, compared to 19 ± 2% by the combined oxidative/non-oxidative pentose cycle that allows for hexose phosphate recycling, and 29 ± 8% by the combined oxidative PPP/de novo nucleotide synthesis reactions. By extension, 62 ± 6% of glucose was converted to pyruvate, the metabolism of which resulted in 16 ± 1% of glucose oxidized by mitochondria and 46 ± 6% exported as lactate. The results indicate a surprisingly high proportion of glucose utilized by the pentose cycle and the reactions synthesizing nucleotides, and exported as lactate. While the in vitro conditions to which the neurons were exposed (high glucose, no lactate or other exogenous substrates) limit extrapolating these results to the in vivo state, the approach provides a means of assessing a number of metabolic fluxes within the context of hexose phosphate recycling in the PPP from a minimal set of measurements.Download full-size image
Co-reporter:Natascha Techen, Iffat Parveen, Zhiqiang Pan, Ikhlas A Khan
Current Opinion in Biotechnology (February 2014) Volume 25() pp:103-110
Publication Date(Web):1 February 2014
DOI:10.1016/j.copbio.2013.09.010
•Various molecular biology techniques were applied for DNA barcoding of botanicals.•Well known genomic regions (matK, ITS, psbA-trnH, rbcL) were used for DNA barcoding.•Often several genomic regions were required for maximum identification success.•Several databases with barcodes of botanicals are currently available.•Next generation sequencing: future method of choice for barcoding?Because of the increasing demand for herbal remedies and for authentication of the source material, it is vital to provide a single database containing information about authentic plant materials and their potential adulterants. The database should provide DNA barcodes for data retrieval and similarity search. In order to obtain such barcodes, several molecular methods have been applied to develop markers that aid with the authentication and identification of medicinal plant materials. In this review, we discuss the genomic regions and molecular methods selected to provide barcodes, available databases and the potential future of barcoding using next generation sequencing.Download high-res image (130KB)Download full-size image
Co-reporter:Jianping Zhao, Asok K. Dasmahapatra, Shabana I. Khan, Ikhlas A. Khan
Journal of Ethnopharmacology (8 December 2008) Volume 120(Issue 3) pp:387-393
Publication Date(Web):8 December 2008
DOI:10.1016/j.jep.2008.09.016
Ethnopharmacological relevanceDamiana (Turnera diffusa Willd. Ex Schult) has traditionally been used as an herbal aphrodisiac.Aim of the studyThe study was aimed to investigate the anti-aromatse activity and the estrogenic activity of the constituents isolated from Turnera diffusa.Materials and methodsThe methanolic extract and 24 compounds isolated from the leaves of Turnera diffusa were evaluated for aromatase activity by using a tritiated-water release assay and for estrogenic activity by using yeast estrogen screen (YES) assay.ResultsThe methanolic extract demonstrated a dose-dependent inhibitory activity of the aromatase enzyme with the IC50 value of 63.1 μg/ml. Among the 24 tested compounds, pinocembrin and acacetin showed the most potent inhibition with IC50 values of 10.8 and 18.7 μM, respectively. Estrogenic activity was also observed in the extract and three compounds including apigenin 7-glucoside, Z-echinacin and pinocembrin with EC50 values of 10, 20 and 67 μM, respectively.ConclusionsThe extract of Turnera diffusa and two isolated compounds pinocembrin and acacetin could significantly suppress aromatase activity. Moreover, apigenin 7-glucoside, Z-echinacin and pinocembrin showed estrogenic activity.
Co-reporter:Ikhlas A. Khan, Atul N. Jadhav
Phytomedicine (3 September 2008) Volume 15(Issue 9) pp:781
Publication Date(Web):3 September 2008
DOI:10.1016/j.phymed.2007.11.005
Co-reporter:Chinni Yalamanchili, Vamshi K. Manda, Amar G. Chittiboyina, Rebecca L. Guernieri, William A. Harrell Jr., Robert P. Webb, Leonard A. Smith, Ikhlas A. Khan
Journal of Ethnopharmacology (2 February 2017) Volume 197() pp:211-217
Publication Date(Web):2 February 2017
DOI:10.1016/j.jep.2016.07.069
Ethnopharmacological relevanceAyurveda, an ancient holistic system of health care practiced on the Indian subcontinent, utilizes a number of multi-plant formulations and is considered by many as a potential source for novel treatments, as well as the identification of new drugs. Our aim is to identify novel phytochemicals for the inhibition of bacterial exotoxin, botulinum neurotoxin A (BoNT/A) based on Ayurvedic literature. BoNT/A is released by Clostridium species, which when ingested, inhibits the release of acetylcholine by concentrating at the neuromuscular junction and causes flaccid paralysis, resulting in a condition termed as botulism, and may also lead to death due to respiratory arrest.MethodsFifteen plants were selected from the book ‘Diagnosis and treatment of diseases in Ayurveda’ by Vaidya Bhagwan Dash and Lalitesh Kashyap, based on their frequency of use in the formulations used for the treatment of six diseases with neuromuscular symptoms similar to botulism. Phytochemicals from these plants were screened using in silico, and in vitro methods. Structures of 570 reported phytochemicals from 14 plants were docked inside six reported BoNT/A light chain crystal structures using ensemble docking module in Maestro (Schrödinger, LLE).ResultsFrom the docking scores and structural diversity, nine compounds including acoric acid 1, three flavonoids, three coumarins derivatives, one kava lactone were selected and screened using an in vitro HPLC-based protease assay. The bioassay results showed that several compounds possess BoNT/A LC inhibition of 50–60% when compared to positive controls NSC 84094 and CB7967495 (80–95%).ConclusionFurther testing of the active compounds identified from Ayurvedic literature and structure-activity studies of acoric acid 1 using more sensitive bioassays is under way. The identification of acoric acid 1, a novel scaffold against BoNT/A, exemplifies the utility of Ayurvedic literature for the discovery of novel drug leads.Download high-res image (209KB)Download full-size image
Co-reporter:Cristina Avonto, Amar G. Chittiboyina, Diego Rua, Ikhlas A. Khan
Toxicology and Applied Pharmacology (1 December 2015) Volume 289(Issue 2) pp:177-184
Publication Date(Web):1 December 2015
DOI:10.1016/j.taap.2015.09.027
•A novel fluorescence-based method to detect electrophilic sensitizers is proposed.•A model fluorescent thiol was used to directly quantify the reaction products.•A discussion of the reaction workflow and critical parameters is presented.•The method could provide a useful tool to complement existing chemical assays.Skin sensitization is an important toxicological end-point in the risk assessment of chemical allergens. Because of the complexity of the biological mechanisms associated with skin sensitization, integrated approaches combining different chemical, biological and in silico methods are recommended to replace conventional animal tests. Chemical methods are intended to characterize the potential of a sensitizer to induce earlier molecular initiating events. The presence of an electrophilic mechanistic domain is considered one of the essential chemical features to covalently bind to the biological target and induce further haptenation processes. Current in chemico assays rely on the quantification of unreacted model nucleophiles after incubation with the candidate sensitizer. In the current study, a new fluorescence-based method, ‘HTS-DCYA assay’, is proposed. The assay aims at the identification of reactive electrophiles based on their chemical reactivity toward a model fluorescent thiol. The reaction workflow enabled the development of a High Throughput Screening (HTS) method to directly quantify the reaction adducts. The reaction conditions have been optimized to minimize solubility issues, oxidative side reactions and increase the throughput of the assay while minimizing the reaction time, which are common issues with existing methods. Thirty-six chemicals previously classified with LLNA, DPRA or KeratinoSens™ were tested as a proof of concept. Preliminary results gave an estimated 82% accuracy, 78% sensitivity, 90% specificity, comparable to other in chemico methods such as Cys-DPRA. In addition to validated chemicals, six natural products were analyzed and a prediction of their sensitization potential is presented for the first time.Download high-res image (166KB)Download full-size image
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![Bicyclo[3.1.1]hept-2-en-6-ol,2,7,7-trimethyl-, 6-acetate](http://img.cochemist.com/ccimg/54400/54324-99-1.png)
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![1,6-Dioxaspiro[4.4]non-3-ene, 2-(2,4-hexadiynylidene)-, (E)-](http://img.cochemist.com/ccimg/50300/50257-98-2.png)
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![Bicyclo[3.1.0]hex-2-ene,4-methylene-1-(1-methylethyl)-](http://img.cochemist.com/ccimg/36300/36262-09-6.png)
![Bicyclo[3.1.0]hex-2-ene,4-methylene-1-(1-methylethyl)-](http://img.cochemist.com/ccimg/36300/36262-09-6_b.png)
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![(3Z)-4,11,11-TRIMETHYL-8-METHYLIDENEBICYCLO[7.2.0]UNDEC-3-EN-5-OL](http://img.cochemist.com/ccimg/32300/32214-88-3.png)
![(3Z)-4,11,11-TRIMETHYL-8-METHYLIDENEBICYCLO[7.2.0]UNDEC-3-EN-5-OL](http://img.cochemist.com/ccimg/32300/32214-88-3_b.png)
![2-[(1E)-heptadec-1-en-1-yl]-6-hydroxybenzoic acid](http://img.cochemist.com/ccimg/28800/28759-01-5.png)
![2-[(1E)-heptadec-1-en-1-yl]-6-hydroxybenzoic acid](http://img.cochemist.com/ccimg/28800/28759-01-5_b.png)
![2-hydroxy-6-[(1E)-pentadec-1-en-1-yl]benzoic acid](http://img.cochemist.com/ccimg/28800/28758-98-7.png)
![2-hydroxy-6-[(1E)-pentadec-1-en-1-yl]benzoic acid](http://img.cochemist.com/ccimg/28800/28758-98-7_b.png)
![2-Furanmethanol,tetrahydro-a,a,5-trimethyl-5-[(1S)-4-methyl-3-cyclohexen-1-yl]-,(2S,5S)-](http://img.cochemist.com/ccimg/26200/26184-88-3.png)
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![1H-Cycloprop[e]azulene,decahydro-1,1,7-trimethyl-4-methylene-, (1aR,4aS,7R,7aR,7bS)-](http://img.cochemist.com/ccimg/25300/25246-27-9.png)
![1H-Cycloprop[e]azulene,decahydro-1,1,7-trimethyl-4-methylene-, (1aR,4aS,7R,7aR,7bS)-](http://img.cochemist.com/ccimg/25300/25246-27-9_b.png)
![Bicyclo[3.1.1]heptan-2-one, 6,6-dimethyl-](http://img.cochemist.com/ccimg/25000/24903-95-5.png)
![Bicyclo[3.1.1]heptan-2-one, 6,6-dimethyl-](http://img.cochemist.com/ccimg/25000/24903-95-5_b.png)
![Propanoic acid, 2-methyl-, (1R,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl ester, rel-](/data/chemimg/1163200/24717-86-0.png)
![Propanoic acid, 2-methyl-, (1R,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl ester, rel-](/data/chemimg/1163200/24717-86-0_b.png)
![[1,6]Dioxacyclododecino[2,3,4-gh]pyrrolizine-2,7-dione,3-ethylidene-3,4,5,6,9,11,13,14,14a,14b-decahydro-6-hydroxy-6-(hydroxymethyl)-5-methylene-,(3Z,6S,14aR,14bR)-](http://img.cochemist.com/ccimg/23300/23246-96-0.png)
![[1,6]Dioxacyclododecino[2,3,4-gh]pyrrolizine-2,7-dione,3-ethylidene-3,4,5,6,9,11,13,14,14a,14b-decahydro-6-hydroxy-6-(hydroxymethyl)-5-methylene-,(3Z,6S,14aR,14bR)-](http://img.cochemist.com/ccimg/23300/23246-96-0_b.png)
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![2H-Pyran-3-ol,tetrahydro-2,2,6-trimethyl-6-[(1S)-4-methyl-3-cyclohexen-1-yl]-, (3S,6S)-](http://img.cochemist.com/ccimg/22600/22567-36-8_b.png)
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![Cyclohexene, 3-(1,5-dimethyl-4-hexenyl)-6-methylene-, [S-(R*,S*)]-](http://img.cochemist.com/ccimg/20400/20307-83-9_b.png)
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![2,6,6-trimethylbicyclo[3.1.1]hept-1-ene hydrate](http://img.cochemist.com/ccimg/18000/17974-51-5_b.png)
![5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2s,3r,4s,5s,6r)-3,4,5-trihydroxy-6-[[(2r,3r,4r,5r,6s)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one](http://img.cochemist.com/ccimg/17700/17650-84-9.png)
![5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2s,3r,4s,5s,6r)-3,4,5-trihydroxy-6-[[(2r,3r,4r,5r,6s)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one](http://img.cochemist.com/ccimg/17700/17650-84-9_b.png)
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![Ferrate(2-), [7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-κN21,κN22,κN23,κN24]-, hydrogen (1:2), (SP-4-2)-](/data/chemimg/522800/14875-96-8_b.png)
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![Didymin with HPLC [14259-47-3]](http://img.cochemist.com/ccimg/14300/14259-47-3_b.png)
![4H-1-Benzopyran-4-one,7-[[2-O-(6-deoxy-a-L-mannopyranosyl)-b-D-glucopyranosyl]oxy]-2-(3,4-dihydroxyphenyl)-2,3-dihydro-5-hydroxy-,(2S)-](http://img.cochemist.com/ccimg/13300/13241-32-2.png)
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![Bicyclo[2.2.1]heptan-2-one,3,3-dimethyl-](http://img.cochemist.com/ccimg/13300/13211-15-9_b.png)
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![Spiro[naphth[2,1-c]oxireno[d]pyran-6(3H),3'(4'H)-[2H]pyran]-1,6',9(3aH,5H,10aH)-trione,3-(3-furanyl)hexahydro-4'-hydroxy-7-(1-hydroxy-1-methylethyl)-3a,9a-dimethyl-,(3S,3'S,3aS,4'S,5aR,7R,9aR,9bR,10aS)-](http://img.cochemist.com/ccimg/10200/10171-61-6_b.png)
![[1S-(1α,4aα,5α,7α,7aα)]-1,4a,5,6,7,7a-hexahydro-4a,5,7-trihydroxy-7-methylcyclopenta[c]pyran-1-yl β-D-glucopyranoside](http://img.cochemist.com/ccimg/7000/6926-08-5.png)
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![[1,6]Dioxacyclododecino[2,3,4-gh]pyrrolizinium,3-ethylidene-2,3,4,5,6,7,9,11,13,14,14a,14b-dodecahydro-6,14b-dihydroxy-5,6,12-trimethyl-2,7-dioxo-,(3Z,5R,6R,14aR,14bS)-](http://img.cochemist.com/ccimg/6900/6882-01-5_b.png)
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![Oxireno[4,4a]-2-benzopyrano[6,5-g][2]benzoxepin-3,5,9(3aH,4bH,6H)-trione,1-(3-furanyl)decahydro-11-hydroxy-4b,7,7,11a,13a-pentamethyl-,(1S,3aS,4aR,4bR,6aR,11S,11aR,11bR,13aS)-](http://img.cochemist.com/ccimg/3300/3264-90-2.png)
![Oxireno[4,4a]-2-benzopyrano[6,5-g][2]benzoxepin-3,5,9(3aH,4bH,6H)-trione,1-(3-furanyl)decahydro-11-hydroxy-4b,7,7,11a,13a-pentamethyl-,(1S,3aS,4aR,4bR,6aR,11S,11aR,11bR,13aS)-](http://img.cochemist.com/ccimg/3300/3264-90-2_b.png)
![4H-1-Benzopyran-4-one,3-[4-[[2-O-(6-deoxy-a-L-mannopyranosyl)-b-D-glucopyranosyl]oxy]phenyl]-5,7-dihydroxy-](http://img.cochemist.com/ccimg/3000/2945-88-2.png)
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![7H-Furo[3,2-g][1]benzopyran-7-one, 9-hydroxy-](/data/chemimg/4400/2009-24-7.png)
![7H-Furo[3,2-g][1]benzopyran-7-one, 9-hydroxy-](/data/chemimg/4400/2009-24-7_b.png)
![(1R,3aR,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-3a,5a,5b,8,8,11a-Hexamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysen-9-yl acetate](http://img.cochemist.com/ccimg/1700/1617-68-1.png)
![(1R,3aR,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-3a,5a,5b,8,8,11a-Hexamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysen-9-yl acetate](http://img.cochemist.com/ccimg/1700/1617-68-1_b.png)
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