Estrogenic/antiestrogenic and scavenging properties of (E)- and (Z)-resveratrol

Resveratrol, natural compound found in grapes and wine, has been reported t o have a variety of health benefit properties. Based on the structural simi larity to the synthetic estrogen diethylstilbestrol, we investigated estrog enic/antiestrogenic effects on human breast cancer cell lines, MCF-7 and MV LN, and scavenging properties using DPPH of both (E)- and (Z)-isomers. Both isomers increased the in vitro growth of MCF-7 cell lines at medium concen trations (10 and 25 mu M) whereas the low concentrations (0.1 and 1 mu M) h ad no effect and the high concentration (50 mu M) decreased the cell growth and was cytotoxic. The 25 mu M (E)-isomer alone was able to reduced the pr oliferation induced by the estradiol.-low concentrations of (E)- and (Z)-re sveratrol (0.1 and 1 mu M) and medium concentration 10 mu M (Z)-resveratrol did not interfere with the estrogen receptor. In contrast, medium concentr ations of (E)-resveratrol (10 and 25 mu M) and (Z)-resveratrol (25 mu M) fu nctioned as superagonists of estradiol. Whatever the model used, MCF-7 or M VLN cell lines, (Z)-resveratrol was less effective than (E)-resveratrol. Ex tinction of DPPH and Fe(III) reduction experiments showed that both isomers of resveratrol could act as free radicals scavengers or pro-oxidant compou nds. The properties of low concentrations of resveratrol raise the possibil ity that structure-function studies could lead to the development of more s elective estrogen receptor agonists and antagonists, which could be useful as a therapeutic agent.