Muccuna pruriens seeds are rich source of L-DOPA and its metabolites, which include epinephrine and norepinephrine. Therefore, an increase in dopamine level in the brain following M. pruriens treatment may not only induce the activation of sexual behavior but it may also increase plasma testosterone level. It has been reported recently that L-DOPA and its metabolite dopamine stimulate the hypothalamus and forebrain to secrete gonadotropin releasing hormone (GnRH). This, in turn, upregulates the anterior pituitary gland to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH) causing increased synthesis of testosterone by Leydig cells of the testis. Furthermore, spermatogenesis is controlled by the hypothalamus and anterior pituitary working together. On the basis of the aforestated facts, it may be proposed that increased dopamine level in the brain may not only optimize the release of hormones, including testosterone, leading to increased sexual drive and improved performance, but it may also accomplish reduction of psychological stress. Moreover, treatment with M. pruriens may also contribute to proper functioning of male genital system and facilitate sperm transport, contraction of seminal vesicles and inhibition of lipid peroxidation of spermatozoa. M. pruriens not only helps in reducing psychological stress, but also improves semen quality as it restores antioxidant levels and reduces lipid peroxide content.
