Oligostilbenoids with acetylcholinesterase inhibitory activity from Dipterocarpus alatus.

Phytochemical investigation of the stem wood of Dipterocarpus alatus led to the isolation and characterization of four new oligostilbenoids, dipterocarpols A-D (1-4), together with two known resveratrol oligomers, hopeahainol (5) and hopeafuran (6). The structures of the new compounds were determined by comprehensive spectral analysis including 1D and 2D NMR, and high-resolution MS. The absolute configurations were determined by NOESY and CD spectra. Dipterocarpol A (1) and hopeahainol A (5) showed moderate acetylcholinesterase inhibitory activity with IC50 values of 8.28 µM and 11.28 µM, respectively. Furthermore, the discovery of compound 3 gave the first evidence that the biosynthetic origin of resveratrol aneuploids is related to the loss of a half resveratrol unit by oxidative cleavage.