α-Glucosidase Inhibitors from the Marine-Derived Fungus Aspergillus flavipes HN4-13

Three new butenolide derivatives, flavipesolides A-C (1-3), along with 13 known compounds (4-13, aspulvinone Q monochlorosulochrin, and dihydrogeodin), were isolated from the marine-derived Aspergillus flavipes HN4-13 from a Lianyungang coastal sediment sample. The structures were elucidated by spectroscopic evidence. Compounds 4-6 and 9 were noncompetitive a-glucosidase inhibitors with K-1/IC50 values of 0.43/34, 2.1/37, 0.79/19, and 2.8/90 mu M, respectively. Compounds 1-3, 8, 10, and 13 are mixed a-glucosidase inhibitors with K-i/IC50 values of (2.5, 19)/44, (3.4, 14)/57, (9.2, 4.7)/95, (6.3, 5.5)/55, (1.4, 0.60)/9.9, and (2.5, 7.2)/33 mu M, respectively (IC50, 101 mu M for acarbose and 79 mu M for 1-deoxynojirimycin).