Lindleyin

Lindleyin is a novel phytoestrogen and might trigger many of the biological responses evoked by the physiological estrogens.One herbal extract, Rhei rhizoma (rhubarb), acts as an agonist to both ERalpha and ERbeta. The phytochemical Lindleyin, a major component of rhubarb, might contribute to this estrogenic activity through ERalpha and ERbeta. 4-Hydroxytamoxifen, an ER antagonist, completely reversed the estrogenic activity of Lindleyin. Lindleyin binds to ERalpha in vitro, as demonstrated using a fluorescent polarization assay. The in vivo effect of rhubarb extract was studied using a vitellogenin assay system in the freshwater fish, Japanese medaka (Oryzias latipes) . There were marked increases in serum vitellogenin levels in male medaka exposed to rhubarb extract.