Reproductive Toxicity of Quassia amara Extract: Action on Sperm Capacitation and Acrosome Reaction

Quassia amara is a medicinal plant with several pharmacological properties. There are preliminary reports implicating this plant in male reproductive toxicology. Single daily oral administration of methanol extract of Quassia amara stem bark for 6 weeks resulted in a significant reduction in the weight of the testes, caudal epididymis and seminal vescicle. Caudal epididymal sperm parameters showed evidence of toxicity. The sperm motility, viability, count and volume were significantly reduced (P<0.05). Less than 50% of the caudal epididymal sperm were motile. Total tissue protein of the epididymis of the treated rats was significantly reduced (P<0.05), but no significant difference was recorded in the testicular total tissue protein when compared with the control. Luteinizing hormone and testosterone levels were significantly lower (P<0.01), but no effect was observed on follicle stimulating hormone. Histological section showed that the epididymis is made up of fewer ducts, which are loosely packed together when compared with the control and the ducts contained less amounts of the ductular eosinophilic material. The ductular epithelium however remained normal. No visible lesion was observed in testicular epithelium. In vitro study to verify these results on caudal epididymal sperm of white Fulani cow in an extender solution showed that the reproductive toxic effect of Q. amara is consistent. Sperm parameters declined in the treated groups. Ninety seven percent of the caudal epididymal sperm of the control rats were capacitated and their acrosome reacted after in vitro induction of sperm capacitation by pre-incubation in a modified capacitation medium. However, thirty nine percent of sperm cells from rats treated with Q. amara failed to be capacitated and their acrosome remained intact while thirty three percent failed to undergo the acrosome reaction, though they were capacitated. Only 27% successfully underwent the capacitation and acrosome reactions. Q. amara may have a reproductive specific toxic effect as our results show lack of effect on weight and histology of visceral organs, fasting blood glucose level, lipid profile and liver function.