Spermatogenic Efficacy of Pausinystalia yohimbe (K. Schum.) Pierre ex Beille Roots in Male Rats

Background: The roots of Pausinystalia yohimbe have been traditionally acclaimed as aphrodisiac. In the present study, methanol extract of the root was evaluated for its effect on sexual orientation behaviour and spermatogenesis in albino Wistar rats. Methods: Forty five (45) male albino rats were randomly divided into five groups of nine rats each. Rats in group I (control) were administered 1 mL/kg body weight distilled water (vehicle), group II received 5 mg/kg body weight sildenafil citrate (Viagra), while those in groups III, IV, and V were given 25, 50, and 100 mg/kg body weight, respectively, of methanol extract of Pausinystalia yohimbe root in the same volume. Female albino rats were made receptive by hormonal treatment. Sexual orientation behaviour parameters were monitored on days 1, 7 and 14 by pairing with receptive females. A change in sexual orientation behaviuor was assessed by orientation towards female, towards environment and towards self, while spermatogenic activity was evaluated on day 14. Results: Administration of the extract had pronounced effect on sexual orientation behaviour of male towards the female rats on days 7 and 14. Males treated with the extract displayed more frequent and vigorous anogenital sniffing and mounting as compared to untreated animals. Libido was also at increase in extract treated male rats. The extract had stimulated the spermatogenetic activity and accessory reproductive organs performance in albino rats. The increased spermatogenesis in extract treated groups was confirmed by change in histoarchitecture as evidenced by increase in number of spermatogenic elements and parameters. Conclusion: P. yohimbe exhibited remarkable increase in sexual orientation, libido and spermatogenic activity which are some of the indices that determine the ability of a male to produce viable spermatozoa. These findings support the folk use of this plant as an aphrodisiac.