New butenolide derivatives from the marine-derived fungus Paecilomyces variotii with DPPH radical scavenging activity

摘要

Bioassay-guided fractionation of the marine-derived endophytic fungus Paecilomyces variotii resulted in the isolation of two new butenolides, namely, butyrolactone IX (1) and aspulvinone O (7), together with eight known related congeners, butyrolactones I, IV, V, and VI (2-5), aspernolide A (6), and aspulvinones H, C, and D (8-10). Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison with literature data. All of the isolated butenolides were tested for their activity against DPPH radicals and the results showed that butyrolactones (1-6) possessed potent activity with IC50 values ranging from 38.0 to 186.3 mu M, while aspulvinones (7-10) exhibited significant activities with IC50 values ranging from 11.6 to 29.4 mu M, which are stronger than that of the positive control BHT (with IC50 117.7 mu M). The preliminary structure-activity relationship was discussed. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.