Aphrodisiac Potentials of Pausinystalia yohimbe (K. Schum.) Pierre ex Beille Methanol Root Extract in Male Wistar Rats

Abstract

Background and Objectives: Pausinystalia yohimbe is an evergreen (tree) medicinal plant that is being used across the globe in ethnomedicine to enhance libido in male. Therefore, this study is to investigate the in vitro aphrodisiac potential and acute toxicological effect of P. yohimbe roots in male Wistar rats. Materials and Methods: Forty-five male albino rats were randomly divided into five groups of nine rats each. Rats in Group 1 (control) were administered 1 mL/kg body weight distilled water (vehicle), Group 2 received 5 mg/kg body weight sildenafil citrate (Viagra), while those in Groups 3, 4, and 5 were given 25, 50, and 100 mg/kg body weight, respectively, of methanol extract of P. yohimbe root in the same volume. Female albino rats were made receptive by hormonal treatment. Sexual behavior parameters in male rats were monitored on days 1, 7, and 14 by pairing with receptive females. Computed male sexual behavioral parameters, male serum testosterone concentrations, and acute toxicological assay of the plant were also determined. Results: Oral administration of P. yohimbe root extract at the doses evaluated, except the lowest dosed group on day 1, significantly increased mount, intromission, and ejaculation frequencies (P < 0.05). The latencies of mount and intromission were significantly decreased and ejaculation latency was prolonged. Administration of the extract also reduced the postejaculatory interval significantly. The standard drug (sildenafil citrate) was not effective than the extract. The extract significantly increased the computed male sexual behavioral parameters as well as serum testosterone concentrations, compared with the distilled water control. The toxicity studies showed that there were no acute behavioral changes with zero mortality. Conclusions: The result of this study demonstrates that methanol extract of P. yohimbe root enhances sexual behavior in male rats. The aphrodisiac effects of the plant extract may be related to the increased blood testosterone concentrations caused by the action of bioactive compounds present in the extract, acting via a multitude of central and peripheral mechanisms. Data from this study thus support the folk use of the plant material as an aphrodisiac in males.