Mechanism of action of <i>Pterorhachis</i> <i>zenkeri</i> (Meliaceae), a sexual enhancer: effect on vas deferens contractility

Abstract

Background: Pterorhachis. zenkeri commonly known as “Ayilalou” or “Démareur” is an aphrodisiac plant used by Cameroonian traditional healers to enhance libido and sperm production. This study was undertaken to investigate the aphrodisiac mechanism of P. zenkeri on the contractile activity of vas deferens with regard to its function on ejaculation. Materials and Methods: The proximal parts of rat vas deferens were mounted in a 20 mL organ bath containing Krebs solution at 37°C. Cumulative dose-response curves were recorded with KCl (35-280 mM), adrenaline (7-70 µM) and aqueous extract of P. zenkeri (3,55-21,3 mg/mL). Prazosin (type 1 alpha-adrenergic receptor antagonist, 10 µM), Nifedipine (a specific L-type calcium channel antagonist, 5 µM), 2-AminoethoxydiPhenyl Borate (2-APB, IP3 receptor antagonist, 200 μM) and calcium-free medium were further used to study the mechanism of action. Results: KCl, adrenaline and aqueous extract of P. zenkeri showed a concentration-dependent effect on vas deferens contractibility. Nifedipine and Pazosin partially inhibited the effects of P. zenkeri. In calcium-free medium containing Ethylene Glycol-bis (2-aminoethylether)-N,N,N’N’-tetraacetic acid (EGTA, 1µM), P. zenkeri triggered vas deferens contraction which was completely abolished in the presence of 2-APB. These results suggest that the aqueous extract of P. zenkeri possesses bioactive compounds capable of inducing vas deferens contractions through type 1 alpha adrenergic receptors and mobilization of extra and intracellular calcium. Conclusion: These results confirm the aphrodisiac properties of P. zenkeri through the activation of the emissive phase of ejaculation.