Contraceptive and Estrogenic Effect of a Methanol Extract of Cassia nigricans Leaves in Experimental Animals

The methanol extract of Cassia nigricans Vadl leaves was investigated for its contraceptive activity in mice and rats. The extract dose-dependently (0.5–1.0 g/kg) protected the animals from conception for 1–4 gestational periods in mice and rats. It inhibited fetal implantation, as was confirmed by laparotomy on day 10 of pregnancy. The pups showed significant change in weight and length (p < 0.01) with 0.75 g/kg, compared to control fetal defects. In ovariectomized immature young rats and mice, there was a dose-dependent increase in uterine wet weight (p < 0.001). The extract induced uterotrophic effects or immature vaginal opening and cornification when compared with estrogen-treated groups. Its anticonceptive effect may be due in part to its anti-implantation, estrogenic and/or direct effect on the uterus.