Absolute configuration and conformational analysis of C-glucoside of a resveratrol trimer: Structure of hopeaside E from Hopea utilis

In this study, we isolated a new glucoside of the resveratrol trimer (hopeaside E) from the stem wood of Hopea utilis. The glucoside structure is partially composed of balanocarpol (resveratrol dimer) after oxidative condensation of the (E)-resveratrol-10-C-β-glucopyranoside. The structure elucidation was achieved by spectroscopic analysis including NMR experiments, and the absolute configuration was determined on the basis of the comparative configurational analysis with the β-d-glucopyranosyl group. Conformational analysis was also performed by considering deshielding effects due to aromatic rings using computational methods of molecular modeling. The aglycone has six asymmetric carbons with two aliphatic hydroxyl groups attached to them that has not been reported in any other resveratrol derivative studies.