Four Undescribed Stilbenoid Derivatives from the Aerial Parts of Dendrobium Officinale with Their Α-Glucosidase and Α-Amylase Inhibitory Activity.

In this study, four undescribed bibenzyl derivatives (1-4), together with seven known compounds (5-11) were isolated from the aerial parts of Dendrobium officinale. Their chemical structures were determined to be (7'S,8'S) -9 ''-acetyldendrocandin U (1), (7'S,8'S) -4 '-methoxydendrocandin T (2), (7'R,8'S) -dendrocandin B (3), (1S,2R) -5 '''-methoxydendrofindlaphenol C (4) by analyzing of the spectroscopic data including HR-ESI-MS, 1D-, and 2D-NMR spectra. The absolute configurations of compounds 1-4 were determined by the electronic circular dichroism (ECD) spectra. Compounds 1-3, 5, 10 and 11 inhibited alpha-glucosidase with the IC50 values ranging from 56.3 to 165.3 mu M, compounds 1-3, 5, 7-10 inhibited alpha-amylase with the IC50 values ranging from 65.2 to 177.6 mu M.