Senhua Chen

Aspterpenacids A and B, Two Sesterterpenoids from a Mangrove Endophytic Fungus Aspergillus terreus H010

Two new sesterterpenoids, aspterpenacids A (1) and B (2), with an unusual carbon skeleton of a 5/3/7/6/5 ring system were isolated from the mangrove endophytic fungus Aspergillus terreus H010. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction analysis, and electronic circular dichroism calculations. A biogenetic pathway for 1 and 2 is proposed. Both 1 and 2 showed no significant antibacterial activity or cytotoxicity at 50 μM.

Isocoumarins and benzofurans from the mangrove endophytic fungus Talaromyces amestolkiae possess α-glucosidase inhibitory and antibacterial activities

Six new isocoumarins, compounds 1–4 and 14–15, two new benzofurans, 16–17, along with nine known isocoumarin analogues, 5–13 were obtained from the mangrove endophytic fungus Talaromyces amestolkiae YX1. Their structures were elucidated by analysis of spectroscopic data. The absolute configuration of compounds 4, 14 and 15 were determined by the modified Moshers method and comparison of their CD spectra with dihydroisocoumarins described in the literature. The structure of compound 5 was further confirmed by a single-crystal X-ray diffraction experiment using Cu Kα radiation. Compounds 2, 6, 8, and 10 showed α-glucosidase inhibitory activity with IC50 values of 89.4, 17.2, 36.4, and 38.1 μM, respectively. In the antibiotic assay, compounds 16 and 17 exhibited antibacterial activities with MIC values between 25–50 μg mL−1 against the Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Bacillus subtilis.

Eurothiocin A and B, Sulfur-Containing Benzofurans from a Soft Coral-Derived Fungus Eurotium rubrum SH-823

Two new sulfur-containing benzofuran derivatives, eurothiocin A and B (1 and 2), along with five known compounds, zinniol (3), butyrolactone I (4), aspernolide D (5), vermistatin (6), and methoxyvermistatin (7), were isolated from the cultures of Eurotium rubrum SH-823, a fungus obtained from a Sarcophyton sp. soft coral collected from the South China Sea. The new compounds (1 and 2) share a methyl thiolester moiety, which is quite rare among natural secondary metabolites. The structures of these metabolites were assigned on the basis of detailed spectroscopic analysis. The absolute configurations of 1 and 2 were determined by comparison of the experimental and calculated electronic circular dichroism (ECD) data. Compounds 1 and 2 exhibited more potent inhibitory effects against α-glucosidase activity than the clinical α-glucosidase inhibitor acarbose. Further mechanistic analysis showed that both of them exhibited competitive inhibition characteristics.

Bioactive Metabolites from Mangrove Endophytic Fungus Aspergillus sp. 16-5B.

Chemical investigation of the endophytic fungus Aspergillus sp. 16-5B cultured on Czapek’s medium led to the isolation of four new metabolites, aspergifuranone (1), isocoumarin derivatives (±) 2 and (±) 3, and (R)-3-demethylpurpurester A (4), together with the known purpurester B (5) and pestaphthalides A (6). Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. The absolute configuration of Compound 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra, and that of Compound 4 was revealed by comparing its optical rotation data and CD with those of the literature. The structure of Compound 6 was further confirmed by single-crystal X-ray diffraction experiment using CuKα radiation. All isolated compounds were evaluated for their α-glucosidase inhibitory activities, and Compound 1 showed significant inhibitory activity with IC50 value of 9.05 ± 0.60 μM. Kinetic analysis showed that Compound 1 was a noncompetitive inhibitor of α-glucosidase. Compounds 2 and 6 exhibited moderate inhibitory activities.

Polyketides from the Mangrove-Derived Endophytic Fungus Nectria sp. HN001 and Their α-Glucosidase Inhibitory Activity

Four new polyketides: nectriacids A–C (1–3) and 12-epicitreoisocoumarinol (4), together with three known compounds: citreoisocoumarinol (5), citreoisocoumarin (6), and macrocarpon C (7) were isolated from the culture of the endophytic fungus Nectria sp. HN001, which was isolated from a fresh branch of the mangrove plant Sonneratia ovata collected from the South China Sea. Their structures were determined by the detailed analysis of NMR and mass spectroscopic data. The absolute configuration of the stereogenic carbons for compound 4 was further assigned by Mosher’s ester method. All of the isolated compounds were tested for their α-glucosidase inhibitory activity by UV absorbance at 405 nm, and new compounds 2 and 3 exhibited potent inhibitory activity with IC50 values of 23.5 and 42.3 μM, respectively, which were more potent than positive control (acarbose, IC50, 815.3 μM).

New depsidones and isoindolinones from the mangrove endophytic fungus Meyerozyma guilliermondii (HZ-Y2) isolated from the South China Sea.

Summary Three new depsidones, botryorhodines E–G (1–3), and two new isoindolinones, meyeroguillines A and B (7 and 9), along with five known compounds were isolated from an endophytic fungus Meyerozyma guilliermondii, derived from the mangrove plant Kandelia obovata. Their structures were elucidated by 1D and 2D NMR spectroscopy and high resolution mass spectrometry (HREIMS). Compounds 1–6 exhibited strong α-glucosidase inhibitory activity with IC50 values ranging from 2.1 to 13.3 μM. Moreover, kinetic studies of compounds 2 and 6 showed that both of them were noncompetitive inhibitors of α-glucosidase.

Polyketides with Immunosuppressive Activities from Mangrove Endophytic Fungus Penicillium sp. ZJ-SY2

Nine polyketides, including two new benzophenone derivatives, peniphenone (1) and methyl peniphenone (2), along with seven known xanthones (3–9) were obtained from mangrove endophytic fungus Penicillium sp. ZJ-SY2 isolated from the leaves of Sonneratia apetala. Their structures were elucidated on the basis of MS, 1D, and 2D NMR data. Compounds 1, 3, 5, and 7 showed potent immunosuppressive activity with IC50 values ranging from 5.9 to 9.3 μg/mL.

A new α-pyrone from the mangrove endophytic fungus Phomopsis sp. HNY29-2B

Abstract A new α-pyrone derivative, phomopyrone A (1), together with two known compounds (2–3), was isolated from the culture of the mangrove endophytic fungus Phomopsis sp. HNY29-2B. Their structures were determined by detailed analysis of spectroscopic data. The configuration of 1 was further confirmed by X-ray diffraction. All isolated compounds were evaluated for antibacterial and antioxidative activities. Compound 2 exhibited antibacterial activities with minimal inhibition concentration (MIC) values of 25 and 50 μM against Bacillus subtilis and Pseudomonas aeruginosa, and compound 3 showed activities against Staphylococcus aureus and B. subtilis with MIC values of 25 and 50 μM, respectively.

Alkaloids from the mangrove endophytic fungus Diaporthe phaseolorum SKS019

Six new alkaloids including four new chromeno[3,2-c]pyridines, diaporphasines A-D (1-4), and two new isoindolinones, meyeroguillines C and D (6-7), as well as three known compounds meyeroguilline A (5), 5-deoxybostrycoidin (8), and fusaristatin A (9), were isolated from an endophytic fungus Diaporthe phaseolorum SKS019. Their structures were determined by analysis of 1D and 2D NMR and mass spectroscopic data. Compounds 1-9 are alkaloid components reported for the first time from the Diaporthe sp., and diaporphasines A-D (1-4) are the third examples of alkaloids possessing the unique chromeno[3,2-c]pyridine nucleus. All isolated compounds 1-9 were evaluated for their cytotoxic activity in vitro using MDA-MB-435, HepG2, MCF10A, HCT116, and NCI-H460 human cell lines. Compound 8 exhibited cytotoxicity against MDA-MB-435 and NCI-H460 human cancer cell lines with IC50 values of 5.32 and 6.57μM, respectively, and compound 9 showed growth-inhibitory activity against MDA-MB-435 human cancer cell line with IC50 value of 8.15μM.

Antioxidative Polyketones from the Mangrove-Derived Fungus Ascomycota sp. SK2YWS-L

Three novel 2,3-diaryl indone derivatives, ascomindones A−C (1−3), and two new isobenzofuran derivatives, ascomfurans A (4) and B (5), together with four know compounds (6−9) were isolated from the culture of a mangrove-derived fungus Ascomycota sp. SK2YWS-L. Their structures were elucidated on the interpretation of spectroscopic data. 1 and 4 were further constructed by analysis of X-ray diffraction. Antioxidant properties based on 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging activities and the ferric reducing ability power (FRAP) of the new compounds were assayed. All of them exhibited significant effects, of which 1 showed more potent activity than ascorbic acid in scavenging DPPH radical with IC50 value of 18.1 μM.