RESVERATROL - ISOMERIC MOLAR ABSORPTIVITIES AND STABILITY

Resveratrol has attracted interest as a wine constituent that may redu ce heart disease. Published data on the molar absorptivity and chemica l stability of cis- and trans-resveratrol have varied greatly. Accurat e values for UV absorbance for trans-resveratrol [UV lambda(max) (EtOH ) nm (epsilon) 308 (30 000)] and cis-resveratrol [UV lambda(max) (EtOH ) nm (epsilon) 288 (12 600)] were determined and are used to improve c hromatographic quantitation methods. Trials conducted under a variety of commonly encountered laboratory conditions show that trans-resverat rol is stable for months, except in high-pH buffers, when protected fr om light. cis-Resveratrol was stable only near pH neutrality when comp letely protected from light.