Four butyrolactones and diverse bioactive secondary metabolites from terrestrial Aspergillus flavipes MM2: isolation and structure determination

Abstract

Abstract The chemical constituents and biological activities of the terrestrial Aspergillus flavipes MM2 isolated from Egyptian rice hulls are reported. Seven bioactive compounds were obtained, of which one sterol: ergosterol (1), four butyrolactones: butyrolactone I (2), aspulvinone H (3), butyrolactone-V (6) and 4,4'-diydroxypulvinone (7), along with 6-methylsalicylic acid (4) and the cyclopentenone analogue; terrien (5). Structures of the isolated compounds were deduced by intensive studies of their 1D & 2D NMR, MS data and comparison with related structures. The strain extract and the isolated compounds (1-7) were biologically studied against number of microbial strains, and brine shrimp for cytotoxicity. In this article, the taxonomical characterization of A. flavipes MM2 along with its upscale fermentation, isolation and structural assignment of the obtained bioactive metabolites, and evaluate their antimicrobial and cytotoxic activities were described.