EFFECT OF WALNUT (TETRACARPIDIUM CONOPHORUM) LEAF EXTRACT ON SOME BIOMOLECULES LINKED WITH ERECTILE DYSFUNCTION AND MALE INFERTILITY

Abstract

Walnut (Tetracarpidium conophorum (Mull. Arg.) Hutch. & Dalz) leaf is one of the medicinal plants used as male fertility enhancers and its usage in traditional systems of medicine has been on record for a long time but its mechanisms of action has not been fully understood. Therefore, this study was undertaken to investigate the effect of this plant on some biomolecules linked with erectile dysfunction and male infertility. The aqueous extract of the plant leaf was prepared and used for the in vitro analyses. The total phenolic content, total flavonoids content and antioxidant properties of the extract were determined. The ability of the extract to inhibit arginase, Acetyl choline esterase (AChE) and Angiotensin-I-converting enzyme (ACE) activities were also determined. Subsequently, the phenolic constituents were characterized using high performance liquid chromatography coupled to diode array detector (HPLC-DAD). The in vivo oral toxicity test (acute and sub-acute) was conducted on rats to determine safety dosage. Fertility potential of the aqueous extract was also accessed in experimental rats under normal and ethanol-induced infertility conditions. Phytochemical investigations revealed that the extract is rich in vitamin C, phenolics and flavonoid. The extract has antioxidant properties and inhibited arginase, AChE and ACE activities in vitro. HPLC-DAD characterization of the extract revealed the distribution of various phenolic acids and flavonoids. In vivo acute study of single oral administration of 3.5 g/kg dose does not produce mortality or significant behavioural changes during 24 hours observation. In the sub-acute study, the extract (500, 1000, 1500, 2000 mg/kg/bwt/day) administered for a period of 28 days showed no mortality or morbidity. The extract at all doses caused hyperprotienaemic effect but does not show any effect on biomarkers of renal and kidney damage. Furthermore, under normal condition, the extract improved the in vivo antioxidant status, functional biomarkers of spermatogenesis and significantly (P ≤ 0.05) increased the key markers linked with spermatogenesis and fertility [3 β-hydroxyl steroid dehydrogenase (3 β –HSD), 17 β-hydroxyl steroid dehydrogenase (17 β-HSD), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, sperm count, sperm motility and sperm viability]. The extract was found to significantly (P ≤ 0.05) reverse the toxic assaults imposed by ethanol on reproductive tissues and seminal qualities of rats under ethanol-induced infertility condition. Conclusively, walnut leaf possesses fertility enhancing properties and may have useful effects on spermatogenesis and the functionality of sperm cells in male rats.