Monomeric and oligomeric flavanols are agonists of membrane androgen receptors.

The present work reports a new mode of action of the naturally occurring flavanols catechin and epicatechin and their dimers B2 and B5, in the breast cancer T47D cell line, namely, their interaction with membrane androgen receptors. We show that monomeric and dimeric flavanols are complete (B2) or partial displacers of radiolabeled testosterone bound on T47D membranes, with affinities ranging from 1.7 (B5) to 82.