Four Eremophilane Sesquiterpenes from the Mangrove Endophytic Fungus Xylaria sp BL321

Three new eremophilane sesquiterpenes (1-3) were isolated from the mangrove endophytic fungus Xylaria sp. BL321 together with 07H239-A (4), a known analogue of the new compounds. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. Compound 4 showed activation activity on alpha-glucosidase at 0.15 mu M (146%), and then, 4 gradually produced inhibitory activity on alpha-glucosidase with increasing concentration, and the IC50 value is 6.54 mu M.