Ovariectomy lowers urine levels of unconjugated (+)-catechin, (-)-epicatechin, and their methylated metabolites in rats fed grape seed extract.

Abstract Steroid hormones modulate expression of enzymes that metabolize xenobiotics, including dietary supplements. Half of the human population undergoes menopause, yet the effect of this age-related loss of ovarian steroid hormones on the metabolism of dietary supplements has yet to be determined. Grape seed extract (GSE) is a dietary supplement comprised of monomeric and oligomeric catechins and has health benefits in models of age-related diseases.