Abstract

The estrous cycle disruptor effect of an ethanolic extract (EMATst) from Buddleja globosa leaves and standardized in its main component (verbascoside) was determined in rats after the subcutaneous administration of EMATst. Binding of EMATst and verbascoside to the estrogen receptor (ER) of EMATst and verbacoside was also measuredestablished. EMATst produced a significant alteration inof the estrous cycle only at the highest dose (10-5 M), which could be attributed to an antiestrogenic effect. The Bbinding of EMATst and verbascoside to the ER was competitive and occurred in concentrations 1000 times greater than that of 17 beta-estradiol.