Effect of ethanol extract of Rivea hypocrateriformis on the estrous cycle of the rat.

The ethanol extract of Rivea hypocrateriformis was administered orally at the dose levels of 200 and 400 mg/kg body weight to adult albino rats and resulted in an irregular estrous cycle with shortened estrus and metestrus, and with lengthened proestrus in non-dose dependent manner. Significant decreases in number of graffian follicles and corpora lutea and significant increases in number of atretic follicles in treated rats during experimental period indicated the antiovulatory effect of the extract. Increases in the weight of the uterus, its thickness and diameter indicated the uterotrophic effect of the extract. The significant increase in the level of cholesterol in the tissues of treated rats indicated the inhibition of steroidogenesis of cholesterol by ovarian endocrine tissues. Restoration of normal estrous cycles after withdrawal of treatment indicate the reversible effect of ethanol extract in rats.

Antiimplantation and pregnancy interruption efficacy of Rivea hypocrateriformis in the rat.

Petroleum ether, chloroform, ethanol and distilled water extracts of the aerial parts of the plant Rivea hypocrateriformis (Convolvulaceae) were tested for antiimplantation and pregnancy interruption properties in female albino rats. Among these, the ethanol extract was found to be most effective in causing significant antiimplantation and interruption of early pregnancy. The antifertility activity of ethanol extract was reversible on exogenous administration of hydroxy progesterone. However, the same ethanol extract was found to be ineffective in interruption of late pregnancy. Among the four extracts subjected to preliminary phytochemical screening, the active ethanol extract showed positive tests for alkaloids, glycosides, saponins, tannins and phenolic compounds.