Bioassay-guided isolation of metabolites from cultures of the plant-derived fungus Emericella sp. TJ29 yielded three new terpene–polyketide hybrid meroterpenoids, emervaridones A–C (1–3), two new polyketides, varioxiranediols A and B (5 and 6), and three known analogues (4, 7, and 8). The structures and absolute configurations of these new compounds were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, Mo2(OAc)4-induced electronic circular dichroism (ECD) data, and ECD calculations. To date, only one compound (4) bearing the emervaridone-type carbocyclic skeleton has been reported. The structures of emervaridones A–C (1–3) are new members of this type of natural product, and 1 features the first example of an α-directional H-7′ in this structural category. Compounds 1 and 5 were active against five drug-resistant microbial pathogens [methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, extended-spectrum β-lactamase-producing Escherichia coli (ESBL-producing E. coli), Pseudomonas aeruginosa, and Klebsiella pneumoniae] with minimum inhibitory concentration (MIC) values in the micrograms per milliliter range. Notably, the inhibitory effect of emervaridone A (1) against ESBL-producing E. coli was comparable to that of the clinically used antibiotic amikacin, with an MIC value of 2 μg/mL. Compounds 1 and 5, both with low toxicities to mammalian cells, were bacteriostatic and bactericidal, respectively. Importantly, these two compounds may provide novel chemical scaffolds for the discovery of antibacterial agents for drug-resistant microbial pathogens.

The new polyprenylated acylphloroglucinol derivatives 1–15 and the known furohyperforin (16) were isolated from the stems and leaves of Hypericum perforatum. Their structures were determined by analyses of NMR and HRESIMS data. Their absolute configurations were elucidated by a combination of electronic circular dichroism (ECD) and Rh2(OCOCF3)4-induced ECD, as well as X-ray diffraction crystallography. The new hyperforatin F (9) contains a unique acetyl functionality at C-1 of the bicyclo[3.3.1]nonane core. Hyperforatins G (10) and H (11) are similarly the first examples of naturally occurring [3.3.1]-type polycyclic prenylated acylphloroglucinols possessing a carbonyl functionality at C-32. The compounds were tested for their acetylcholinesterase (AChE) inhibitory activities and cytotoxic activities against a panel of human tumor cell lines. Compounds 3, 5, 6, 8, and 9 exerted moderate inhibitory activities (IC50 3.98–9.13 μM) against AChE.

Bioassay-guided isolation of cultures of Aspergillus sp. TJ23 yielded a novel terpene-polyketide hybrid spiromeroterpenoid, spiroaspertrione A (1), bearing a unique spiro[bicyclo[3.2.2]nonane-2,1′-cyclohexane] carbocyclic skeleton, and a new biointermediate, andiconin B (2). Their structures and absolute configurations were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compound 1 demonstrated potent resensitization of oxacillin against methicillin-resistant Staphylococcus aureus by lowering the oxacillin minimal inhibitory concentration up to 32-fold from 32 to 1 μg/mL.

Two new functionalized ergostane-type steroids, phomopsterones A (1) and B (2), were isolated from the plant-derived Phomopsis sp. TJ507A. Their structures were determined on the basis of spectroscopic data, a modified Mosher’s method, X-ray crystallographic analysis, and quantum chemical calculations. Compound 1 is an unprecedented ergosteroid featuring a rearranged bicyclo[3.3.1]nonane motif resulting from B-ring scission and a subsequent 180° rotation of the ring A during biosynthesis. Compound 2 exhibited anti-inflammatory activity.

ObjectiveTo study the chemical constituents of whole plant of Phyllanthus urinaria and their biological activity.MethodsThe chemical constituents were isolated and purified by repeated column chromatography over silica gel, Rp-C18 (reverse phase), MCI, and Sephadex LH-20, as well as semi-preparative HPLC. NMR spectroscopic analyses were used for the structure identification. In this case, the inhibitory rate of NO production of the isolated triterpenoids was evaluated.ResultsSeven triterpenoids, identified as 28-norlup-20(29)-ene-3,17β-diol (1), betulin (2), β-betulinic acid (3), 3-oxofriedelan-28-oic acid (4), oleanolic acid (5), 3R-E-coumaroyltaraxerol (6), and 3R-Z-coumaroyltaraxerol (7), were isolated and identified from the whole plants of P. urinaria. Compounds 1–5 exerted inhibitory effects against NO production in LPS-induced RAW 264.7 mouse macrophages with the inhibitory rate of NO production ranging from 4.0% to 27.8% at the concentration of 25 μmol/L.ConclusionTo the best of our knowledge, this is the first report of compounds 1–4, 6, and 7 from the family Euphorbiaceae. Compounds 1–5 exhibited inhibitory effects against NO production in LPS-induced RAW 264.7 mouse macrophages.

Eighteen compounds, including eight new cassane-type furanoditerpenoids, 3β-hydroxyphanginin H (1), 3β-acetoxyphanginin H (2), 7β-acetoxyphanginin H (3), 7β-hydroxyphanginin H (4), 4-epi-3β-hydroxycaesalpinilinn (5), 4-epi-3β-acetoxycaesalpinilinn (6), 20-acetoxytaepeenin D (7), and tomocin E (8), along with 10 known compounds (9–18) were isolated from the roots of Caesalpinia decapetala. Compounds 1–13 were isolated from C. decapetala for the first time. The new compounds with their absolute configurations were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1, 4, 5, 7, and 11 exhibited inhibitory activities against the SW1990 human pancreatic cancer cell line with IC50 values ranging from 2.9 to 8.9 μM.

Hyperhexanones A (1) and B (2), two novel polycyclic polyprenylated acylphloroglucinol (PPAPs) derivatives, were isolated from Hypericum sampsonii. Compound 1 possesses a novel 1,2-seco-bicyclo[3.3.1]-PPAP skeleton, which represents a crucial intermediate from bicyclo[3.3.1]-PPAPs to the peculiar cyclohexanone monocyclic-PPAPs (CM-PPAPs). A plausible biogenetic pathway was proposed to discuss the origins of the CM-PPAPs.

Armochaeglobines A (1) and B (2), two indole-based cytochalasan alkaloids with new carbon skeletons, were obtained from the fungus Chaetomium globosum TW1-1, which was first isolated from the arthropod Armadillidium vulgare. Their structures were elucidated by extensive spectroscopic analyses, ECD calculation, and single-crystal X-ray diffraction analysis. Interestingly, compound 1 featured a unique tetracyclic 5/6/7/5 fused ring system and 2 possessed a rare 12-membered carbon scaffold.

Ten new cytochalasan alkaloids, termed armochaetoglobins A–J (1–10), and four known chaetoglobosins (11–14) were isolated from a methanol extract of Chaetomium globosum TW1-1, a fungus isolated from the medicinal terrestrial arthropod Armadillidium vulgare. Their structures were elucidated by a combination of spectroscopy, single-crystal X-ray crystallography, and ECD calculations. Armochaetoglobins A–E (1–5) represented the first examples of seco-chaetoglobosins arising from an oxidative cleavage of C-19 and C-20. Among these compounds, armochaetoglobin A (1) features an unusual pyrrole ring. The cytotoxic activities of 2–10 were evaluated, and armochaetoglobin H (8) showed moderate inhibitory activities against five human cancer cell lines, with IC50 values ranging from 3.31 to 9.83 μM.

Two new adamantyl-like polyprenylated acylphloroglucinols, hyperattenins J (1) and K (2), were isolated from the aerial parts of Hypericum attenuatum choisy. Their structures and absolute configurations were elucidated by rigorous spectroscopic analyses including NMR, HRESIMS, and electronic circular dichroism (ECD). Hyperattenin J (1) features by a unique furan-fused adamantyl core structure with an unusual hemiacetal group. Hyperattenin K (2) exhibited inhibitory effects on HIV-1 replication in C8166 cells and moderate cytotoxicity against the HL-60 and A-549 cell lines. The possible biogenetic pathway of 1 is also discussed.Hyperattenin J (1) features a unique furan-fused adamantyl skeleton and an unusual hemiacetal group. Hyperattenin K (2) exhibited inhibitory effects on HIV-1 replication in C8166 cells and moderate cytotoxicity against the HL-60 and A-549 cell lines.

•Spirocyclic acylphloroglucinols, named hyperascyrones A–H, were isolated from H. ascyron.•Their absolute configurations were determined by ECD.•Structures of previously reported tomoeones C, D, G, and H were revised.•Hyperascyrones A–H were evaluated for their cytotoxic and anti-HIV-1 activities.Eight polyprenylated spirocyclic acylphloroglucinol derivatives (PSAPs), hyperascyrones A–H, were isolated from the aerial parts of Hypericum ascyron Linn., together with six known analogs. Their structures were established by spectroscopic analyses including HRESIMS, 1D and 2D NMR, and their absolute configurations were determined by electronic circular dichroism calculations (ECD, Gaussian 09). Structures of previously reported tomoeones C, D, G, and H were revised. Hyperascyrones A–H were evaluated for their cytotoxic and anti-HIV-1 activities, with hyperascyrones C and G exhibiting significant cytotoxicities against HL-60 cell lines with IC50 values of 4.22 and 8.36 μM, respectively. In addition, the chemotaxonomic significance of these compounds was also discussed.Polyprenylated spirocyclic acylphloroglucinol derivatives (PSAPs), named hyperascyrones A–H, were isolated from aerial parts of Hypericum ascyron Linn. Their absolute configurations were determined by electronic circular dichroism calculations.

Hyperisampsins A–D (1–4), with tetracyclo[6.3.1.13,10.03,7]tridecane skeletons and seven biogenetically related congeners (5–11), were isolated from Hypericum sampsonii. Their structures were elucidated by comprehensive spectroscopic techniques. The absolute configuration of 1 was established by ECD calculations, and those of 5 and 9 were confirmed by single X-ray crystallographic analyses. Hyperisampsins A and D showed potent anti-HIV activities with EC50 of 2.97 and 0.97 μM and selectivity index of 4.80 and 7.70, respectively.

A pair of unprecedented enantiomers (1a/1b) of cyclohexylethanoid bearing an unusual trioxabicyclo[4.2.1]nonane ring, along with two known structurally related cyclohexylethanoids, (+)-rengyolone (2) and cleroindicin E (3), were isolated from the aerial parts of Clerodendrum bungei. The structures and absolute configurations of the enantiomers were determined by comprehensive spectroscopic analysis, single-crystal X-ray diffraction, and quantum mechanical calculation of the electronic circular dichroic (ECD) spectra. The postulated biogenetic pathway of 1a/1b was also discussed.

Chemical investigations on the EtOAc extract of the cultures of Colletotrichum capsici afforded a novel indole–pyrazine alkaloid embodying a structurally unique C16N3-type skeleton, colletotrichumine A (1), together with five known steroids (2–6). Their structures were elucidated by spectroscopic analysis and that of 1 was further confirmed by a single-crystal X-ray diffraction method. The plausible biogenetic pathway of 1 was also discussed.

•Twenty-three metabolites were isolated and identified from Phyllanthus urinaria.•Compound 15 was obtained as a new natural product.•Compounds 3–5, 7, 13, and 15–18 were isolated from Euphorbiaceae for the first time.•It is the first characterization of 1, 2, 6, 8, 10–12, and 22 from P. urinaria.•The chemotaxonomic significance of the isolated compounds is summarized.

Three pairs of new 8-O-4′-type dinorneolignan enantiomers, (±)-acortatarinowins A–C (1a/1b–3a/3b), a pair of new 8-O-4′-type (4a/4b) and a pair of rare C7–C8′-type (5a/5b) neolignan enantiomers, (±)-acortatarinowins D and E, and a pair of new furofuran-type lignan enantiomers, (±)-acortatarinowin F (6a/6b), along with two pairs of known lignan enantiomers (7a/7b and 8a/8b), were obtained from the rhizomes of Acorus tatarinowii. The separation of 1–8 by chiral HPLC using a Daicel IC column led to the isolation of eight pairs of enantiomers, 1a/1b–8a/8b, which had variable enantiomeric excess (ee) values of approximately 66, 71, 63, 60, 0, 38, 48, and 75%, respectively. The structures were elucidated by extensive spectroscopic and chemical methods, and their absolute configurations were determined by a combined analysis of single-crystal X-ray diffraction and a modified Mosher’s method, assisted by experimental and calculated electronic circular dichroism data. Among them, compounds 1a, 3a, 6b, 8a, and 8b showed weak inhibitory activities against NO production in activated macrophages with IC50 values ranging from 23.3 to 38.0 μM, respectively.