Antifertility and fetotoxic activities of Acanthus montanus aqueous extract in Wistar rats.

Acanthus montanus T. Anderson (Acanthaceae) possesses several medicinal properties; it is used in Cameroon as a folk medicine to treat pain, inflammation and threatened abortion. The aim of this study was to determine the effect of A. montanus aqueous extract on the estrous cycle pre- and postimplantation in rats and its mechanism of action. The estrous cycles of Wistar rats were monitored before, during and after oral administration of distilled water (control) or aqueous extract (62.5, 125, 250, 500, 1000 mg/kg/day). Furthermore, pregnant rats received the above doses of aqueous extract on days 1-6 (preimplantation) or 6-15 (postimplantation) of gestation and were sacrificed on day 8 or 20 of pregnancy, respectively. Moreover, aqueous extract (500 and 1000 mg/kg/day) was given to ovariectomized rats in the presence or absence of exogenously administered estrogen and/or progesterone and uterine weight and deciduoma count were evaluated. The extract, irrespective of dose, reversibly prolonged the metestrous and occasionally the diestrous stages of the estrous cycle. The extract did not alter the uterine wet weight or deciduoma count, suggesting a lack of estrogenic and progestational effects. At 1000 mg/kg/day, the extract caused appreciable preimplantation losses of 36.8 +/- 6.5% (P < 0.05), while none of the doses caused postimplantation losses. The extract also caused delayed fetal growth.