With the oxidation treatment, eighteen compounds were separated from 20(S)-ginsenoside Rg2, Rh1, protopanaxatriol(PPT) and their 20(R)-epimers in total and cytotoxicity of most of them was evaluated against three human cancer cell lines HeLa, A549 and MCF-7 by 3-(4,5-dimetylthiazol-z-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. Their structures were confirmed by means of nuclear magnetic resonance(NMR) and mass spectrometry and the results were compared with those of previous literature. In this study, we systematically semisynthesized all four ocotillol type saponins, i.e., (20S, 24S), (20S, 24R), (20R, 24S) and (20R, 24R). All the configurations at C20 kept the same with their starting materials. Meanwhile a pair of C24 epimers was generated in terms of ocotillol type saponins. In addition, seven compounds(4―8, 13 and 14) were reported firstly. The cytotoxic results distinguished the ocotillol type products(6, 7, 13 and 14) from 20(R)-PPT and 20(R)-ginsenoside Rh1, which possessed better cytotoxicities than their correspondents from 20(S)-epimers against HeLa cells, and the carbonyl group at C3 can improve the cytotoxicity, which helped us to gain deeper insight into Ocotillol type saponins.

Food allergy has become a worldwide problem. To find an effective way to reduce the allergic effect of allergen is an interesting topic. In this work, the interaction between ovalbumin(OVA) and tangeretin was studied by means of spectroscopy, molecular docking calculation and animal experiment. As the results show, static quenching of fluorescence intensity happened due to the interaction between OVA and tangeretin. Binding constants, binding sites, and thermometric parameters were obtained. The conformation changing of OVA occurred due to the interaction between it and tangeretin. The molecular docking calculation results show that the epitopes Arginine 84(ARG84), Leucine 87(LEU87), Asparagine 88(ASN88), Serine 103(SER103), Arginine 104(ARG104), Leucine 124(LEU124), Arginine 126(ARG126), Glycine 127(GLY127), Glycine 128(GLY128) and Tryptohan 148(TRP148) of OVA were occupied by tangeretin after the docking, which means tangeretin may have some inhibition effects. As the results of animal experiments, the amount of IgE and lung tissue sections of female BALB/c mice in different groups show that tangeretin with different concentrations has better effects than dexamethasone. In conclusion, the tangeretin may have the effects to reduce the allergic effects of OVA via occupying the IgE-binding epitopes of OVA.

In this paper, a graphene-based magnetic nanocomposite (Fe3O4@G) was synthesized by covalent bonding. The presence of Fe3O4 was characterized by fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy (SEM), and transmission electron microscopy. Subsequently, the Fe3O4@G was used as adsorbent for the extraction of eight organochlorine pesticides in orange juice samples prior to their gas chromatography mass spectrometry detection. Various experimental parameters affecting the extraction efficiencies, such as the amount of Fe3O4@G, extraction time, the pH of the sample solution and desorption conditions were investigated. Under optimized experimental conditions, good linearity existed in the range of 1.0–200.0 ng mL−1 for all the analytes with the correlation coefficients (R2) ranging from 0.9904 to 0.9992. The limits of detection (S/N = 3) of the method for the compounds were between 0.01 and 0.05 ng mL−1. Good reproducibilities were obtained with the relative standard deviations (RSDs) below 9.6 %. The recoveries of the method were in the range between 73.8 and 105.4 % with RSDs less than 7.7 %.

A method combining solid-phase extraction and high-performance liquid chromatography (SPE–HPLC) has been developed for analysis of ten rare ginsenosides including 20(R)-Rh1, 20(S)-Rh1, 20(R)-Rg3, 20(S)-Rg3, Rg5, Rk1, Rg6, F4, Rk3, and Rh4 in three kinds of injection (Shenfu, Shenmai, and Shengmai). Waters Oasis HLB SPE columns were used to clean and enrich the sample. An Eclipse XDB-C18 column was used to separate the analytes, with water and acetonitrile as mobile phase components under gradient elution conditions at 30 °C. There were good linear correlations between the signals measured and the concentrations of the ten analytes (r2 ≥ 0.9996). Intraday and interday precision were both better than 2.19% and average recovery ranged from 95.25 to 108.83%. The proposed method was successfully applied to determination of the ten analytes in different batches of the injections and the results indicated the method is simple, rapid, and accurate. The proposed method could be used for quality control during manufacture of the injections.

The interaction between three kinds of flavonoids and bovine serum albumin (BSA) was investigated by fluorescence and UV–vis absorption spectrometry. The results indicated that flavonoids have strong ability to quench the intrinsic fluorescence of BSA by forming complexes. The binding constants, number of binding sites, thermodynamic parameters and energy transfer mechanisms were also investigated. Conformation change of BSA was observed from synchronous, three-dimensional fluorescence and circular dichroism spectrum.

The interaction between taxifolin and bovine serum albumin (BSA), and the effects of some common ions on their interaction, were investigated by fluorescence and UV-visible absorption spectroscopy. The results indicate that taxifolin has a strong ability to quench the intrinsic fluorescence of BSA through a static quenching process. According to values of the thermodynamic parameters, the hydrophobic force plays a major role in the interaction. Based on Főster’s non-radiation theory, the energy transfer distances between BSA and taxifolin in the absence and presence of some common ions were obtained. The experimental results indicate that the transfer distances are almost unaffected by these ions. The conformation of BSA undergoes significant change from the formation of a taxifolin–BSA complex, which was studied by synchronous and three-dimensional fluorescence spectroscopy.

A fast and simple procedure based on matrix solid-phase dispersion was carried out for the extraction of three kinds of lignans, including podophyllotoxin, 4′-demethylpodophyllotoxin and podophyllotoxin glucoside, from the dried roots of Sinopodophyllum emodi Wall. After extraction, the lignans were determined by LC. The main experimental parameters, including type of dispersant, type of clean-up absorbent and type and volume of elution solvent, were examined and optimized. Compared with reflux extraction, the proposed method is simpler, faster and more efficient.

BackgroundRare ginsenosides in Panax quinquefolius L. have strong bioactivities. The fact that it is hard to obtain large amounts of rare ginsenosides seriously restricts further research on these compounds. An easy, fast, and efficient method to obtain different kinds of rare ginsenosides simultaneously and to quantify each one precisely is urgently needed.MethodsMicrowave-assisted extraction (MAE) was used to extract nine kinds of rare ginsenosides from P. quinquefolius L. In this article, rare ginsenosides [20(S)-Rh1, 20(R)-Rh1, Rg6, F4, Rk3, 20(S)-Rg3, 20(R)-Rg3, Rk1, and Rg5] were identified by high performance liquid chromatography (HPLC)–electrospray ionization–mass spectrometry. The quantity information of rare ginsenosides was analyzed by HPLC-UV at 203 nm.ResultsThe optimal conditions for MAE were using water as solvent with the material ratio of 1:40 (w/v) at a temperature of 145°C, and extracting for 15 min under microwave power of 1,600 W. Seven kinds of rare ginsenosides [20(S)-Rh1, 20(R)-Rh1, Rg6, F4, Rk3, Rk1, and Rg5] had high extraction yields, but those of 20(S)-Rg3 and 20(R)-Rg3 were lower. Compared with the conventional method, the extraction yields of the nine rare ginsenosides were significantly increased.ConclusionThe results indicate that rare ginsenosides can be extracted effectively by MAE from P. quinquefolius L. in a short time. Microwave radiation plays an important role in MAE. The probable generation process of rare ginsenosides is also discussed in the article. It will be meaningful for further investigation or application of rare ginsenosides.

•Twenty-two ginsenosides were systematically synthesized and cytotoxicity was evaluated.•Eight ginsenosides were firstly identified based on 1D, 2D NMR and HR-ESIMS.•The number of glycosyl and C-configuration have great influence on the cytotoxicity.•Eleven ginsenosides have cytotoxicity and deserved further investigation.A series of oxidized products have been systematically semisynthesized from 20(S)-ginsenoside Rg3, Rh2, 20(S)-protopanaxadiol (PPD) and their 20(R)-epimers and the majority of these products were evaluated for their cytotoxic activity against HeLa cells and HepG2 cells by MTT assay for the first time. Twenty-two products were obtained and elucidated based on comprehensive 1H NMR, 13C NMR, two-dimensional (2D) NMR, and mass spectral data and the results reported in previous literature. All the four ocotillol type saponins (20S,24R(δ86, δ85); 20S,24S(δ87, δ88); 20R,24R(δ86, δ86); 20R,24S(δ86, δ87) were obtained. In addition, eight compounds (3, 8, 9, 10, 15, 16, 19 and 22) with the cyclized side chain were firstly identified. Most of the tested compounds possessed cytotoxicity to a certain degree against the two types of cells which implied these oxidized products could play a certain role on anti-cancer functions of the raw materials in vivo. Meanwhile, the results proved that the configurations at C-20 or C-24 and the number of glycosyl at C-3 have important influence on the cytotoxicity. The products 1, 2, 11–17, 20 and 22 should possess great activities and deserved further investigation as potential cytotoxic agents.Download full-size image