Nine new isoprenylated depsides, sterenins E-M (1-9), as well as five known compounds (10-14), were isolated from the solid culture of Stereum hirsutum. The structures of the new compounds were elucidated by spectroscopic methods. Their inhibitory activities against yeast α-glucosidase were evaluated in vitro. Compounds 1-4 and 7-14 showed inhibitory activities with IC50 values of 7.62, 3.06, 6.03, 22.70, 36.64, 13.09, 27.52, 25.10, 12.32, 3.31, 23.82, and 14.17 µM, respectively. Compounds 5 and 6 showed no inhibitory activities with IC50 values higher than 50 µM. Therefore, the culture of S. hirsutum and its secondary metabolites could have a potential usage for the development of hypoglycemic drugs.
Georg Thieme Verlag KG Stuttgart · New York.