Aqueous Root Extract of the Anti-Malarial Herbal Cryptolepis sangunolenta (Lindl) Schltr Inhibits Ovulation in Rabbits

The objective of the present study was to assess the effect of the aqueous root extract of Cryptolepis sanguinolenta (cryptolepis), a popular West Africa antimalarial agent on ovulation in rabbits. We demonstrated previously that the aqueous root extract of the plant inhibits reproduction and foetal development in mice. The possible mechanism involved in this reproductive effect and whether the effect is species dependent has yet to be elucidated. Using the rabbit, the present study examined the effect of cryptolepis on pre and post ovulatory events to explore further the mechanism of the reproductive toxicity of cryptolepis. Cryptolepis (62.5-500 mg/kg; p.o) administered five hours before ovulation inhibited ovulation in rabbits as ovarian histology showed dilated but unraptured ovum. The effects of cryptolepis were similar to diclofenac, an NSAID used as a reference drug. Post ovulatory treatment with cryptolepis (62.5-500 mg/kg; p.o) had little effect on ovarian histology but decreased the implantation index. This study shows that the anti-conceptive effects of cryptolepis involve inhibition of ovulation and early post ovulatory events in the rabbit.