Diverse meroterpenoids with α-glucosidase inhibitory activity from Ganoderma cochlear

Three new meroterpenoids, cochlearins J-L (1-3) and three known meroterpenoids (4-6) were isolated from the fruiting bodies of Ganoderma cochlear. NMR (1H and 13C NMR, 1H -1H COSY, HSQC, HMBC and ROESY), and HRESIMS were employed for the structure elucidation of new compounds. The stereostructures of 1-3 were confirmed by calculated ECD and optical rotation methods. Furthermore, compounds (+)-1, (-)-1, (+)-2, (-)-2, (+)-3, (-)-3, and 4-6 were evaluated for their alpha-glucosidase inhibitory activity. The results showed that com-pounds (+)-1, (-)-1 and (+)-2 exhibited stronger inhibition against alpha-glucosidase with IC50 values of 24.18 +/- 1.98, 26.49 +/- 3.20 and 29.68 +/- 2.73 mu M, respectively, compared to the positive control ursolic acid (49.65 +/- 2.21 mu M). The molecular docking experiments reveal that (+)-2 and (-)-2 had different binding mode with alpha-glucosidase, leading to their different inhibition.