Contraceptive Effect of Ethanolic Extract of Dioscorea villosa Tuber on Reproductive Hormones of Female Wistar Rats

The contraceptive effect of oral administration of ethanolic extract of Dioscorea villosa tuber for thirty days on reproductive hormones of female albino rats was investigated. Twenty four female albino rats weighing 150-220g were completely randomized into four groups (A-D) comprising six rats each. Animals in Group A (control) were administered 0.5ml of distilled water. Animals in groups B, C and D received 100, 200 and 400mg/kg body weight of ethanolic extract of Dioscorea villosa tuber respectively for 30 consecutive days. Preliminary phytochemical screening of ethanolic extract of Dioscorea villosa tuber revealed the presence of alkaloids, saponins, flavonoids and cardiac glycosides. The extract at all tested doses decreased serum luteinizing hormone (LH) levels, although this effect was statistically significant only at 100mg/kg body weight (p<0.05). The extract at all doses significantly (p<0.05) decreased the concentration of progesterone in the serum of the animals. A decrease in serum estradiol levels was observed only in animals that received 100 and 200mg/kg body weight of the extract while the 400mg/kg body weight of the extract did not significantly (p>0.05) affect the serum estradiol concentration when compared with the distilled water treated control animals. Serum levels of follicle stimulating hormone (FSH) increased following treatment in a dose-dependent manner, and this effect was statistically significant only at 400mg/kg body weight (p<0.05). These alterations in female rat reproductive hormones by the extract are hormonal imbalance and would have adverse effect on maturation and ovulation of follicles. Consequently, the extract may impair fertility and pregnancy in female rats. Therefore, the ethanolic extract of Dioscorea villosa tuber may be explored as a female contraceptive.