Dietary bioflavonoid quercetin modulates porcine ovarian granulosa cell functions in vitro

Quercetin is a dietary bioflavonoid used widely as a food supplement and is generally recognized as safe. The aim of this in vitro study was to examine the steroid hormone (progesterone and 17- beta estradiol) release, proliferation (PCNA and cyclin B1) and apoptosis (caspase 3 and p53) of porcine ovarian granulosa cells after the addition of quercetin at concentrations 0.01, 0.1, 1, 10 and 100 mu mol L-1. Progesterone release was stimulated at the concentration 10 mu mol L-1. Quercetin neither had any impact on 17-beta estradiol secretion nor on the presence of PCNA. However, a significant enhancement of the occurrence of cyclin B1 was noted except for the lowest concentration 0.01 mu mol L-1. Quercetin did not have any influence on the number of granulosa cells containing caspase 3, but at the concentration 10 mu mol L-1 it inhibited p53 occurrence. Results confirm the safety of quercetin in porcine ovarian granulosa cell model and further suggest its possible concentration-dependent influence on ovarian functions through pathway that may involve progesterone, cyclin B1 and p53.