Secondary metabolites of endophytic fungus Aspergillus ochraceus SX-C7 from Selaginella stauntoniana / 中草药

ABSTRACT

Objective: To study the secondary metabolites of endophytic fungus Aspergillus ochraceus SX-C7 from Setaginella stauntoniana. Methods: The compounds were isolated and purified by silica gel, Sephadex LH-20, C-18 reversed phase column chromatography, and their structures were identified by MS and NMR analyses. Antibacterial activity and inhibitory activity against acetylcholinesterase were studied by doubling dilution and Ellman methods. Results: Ten known compounds were isolated from the secondary metabolites of A. ochrateus SX-C7, and identified as semivioxanthin (1), 6-hydroxy-p-menth-4 (5)-en-3-one (2), flavacol (3), magnolin (4), preussin B (5), circumdatins D (6), isofucosterol (7), sclerotiamide (8), 3β-hydroxyergosta-8,24(28)-dien-7-one (9), and 3-O-β-D-glucopyranosyl stigmasta-5(6),24(28)-diene (10). Conclusion: Compounds 1, 2, 4, 7, and 10 were isolated from A. ochraceus SX-C7 for the first time. The results of the bioactivity assay showed that compound 10 possessed obvious inhibitory activity against Bacillus subtilis with a MIC value of 2 μg/mL, which was at the same grade with positive control. Compound 1 exhibited potent inhibitory activity against acetylcholinesterase with an inhibitory rate of 62.3% (the final concentration was 50 μmol/L.