Amomutsaokols A–K, diarylheptanoids from Amomum tsao-ko and their α-glucosidase inhibitory activity

Abstract

Eleven undescribed diarylheptanoids, amomutsaokols A‒K (1–11), together with 13 known ones (13–24), were isolated from the active fraction of the fruits of Amomum tsao-ko. The structures of the undescribed compounds were determined by extensive 1D and 2D NMR, HRESIMS and ECD calculations. Compounds 3–5, 7, 8, 12, 14 and 19 showed obviously α-glucosidase inhibitory activity with IC50 values ranging from 12.9 to 48.8 μM. An enzyme kinetic analysis indicated that compounds 8 and 9 were α-glucosidase noncompetitive inhibitors with Ki values of 18.5 and 213.0 μM, respectively. This study supported diarylheptanoids as the active constituents of A. tsao-ko with α-glucosidase inhibitory effects.