Vasoactivity, antioxidant and aphrodisiac properties of Caesalpinia benthamiana roots

Caesalpinia benthamiana (=Mezoneuron benthamianum) (Fabaceae) is an African tropical plant whose roots are used in traditional medicine as an aqueous decoction for many purposes, especially for erection impairment but its action mechanism is unknown. The action of Caesalpinia benthamiana on sexual behaviour and some assays on potential modes of action were performed.

The aqueous extract of Caesalpinia benthamiana (AECB) was tested for vasorelaxing properties using isolated rat aortic rings precontracted by phenylephrine. Influence of AECB in the production of endothelial isoform of nitric oxide synthase (eNOS) was measured by quantitative polymerase chain reaction (QPCR) analysis. Scavenging activities versus reactive oxygen species (ROS), such as superoxide anion (O(2).(-)), hydrogen peroxide (H(2)O(2)), and hypochlorous acid (HOCl) were assessed. Action of AECB on the cellular generation of O(2).(-) was also tested in a physiopathology model of oxidative burst using human polymorphonuclear neutrophils stimulated by phorbol myristate acetate. The aphrodisiac properties of AECB administered orally by gavage (50 mg/kg body weight) to male rats were evaluated by observing the sexual behaviour of animals. Finally, a short-term toxicity study was undertaken to establish the therapeutic index of AECB administered orally to rats at high dose (2 g/kg body weight).

C. benthamiana roots are rich in phenolic compounds (gallic acid, resveratrol and tannins). The results showed that AECB had significant vasorelaxing properties. The extract also had a strong radical activity against ROS in cell-free and cellular systems and stimulated eNOS mRNA expression. As for the aphrodisiac activity of AECB in male rats, results have shown that sexual parameters are stimulated. Furthermore, after oral administration at high dose, AECB causes no mortality or changes in rats' behaviour.

AECB enhanced the sexual activity of male rats. This could be partly explained by its vasorelaxant properties, which may be caused by an increase in NO production in vascular bed and a decrease in its destruction.