Pharmacological Effects of Methanolic Extract of Garcinia Kola (Heckel) Seed on the Reproductive Profiles of Some Male Experimental Animals

Abstract

Garcinia kola is commonly consumed in Nigeria in social ceremonies and for leisure purposes. It is speculated to enhance sexual performance in males. The effects of methanolic extract of Garcinia kola seed on the male reproductive profiles of rats were determined at oral doses of 125, 250 and 500 mg/kg for 20 and 60 days respectively. The animals were administered the extract orally for either 20 or 60 days after which analysis of the parameters were carried out using known standard procedures. The acute toxicity test revealed that the LD50 of the methanolic extract is 3125 ± 52.68 mg/. The extract caused significant increase in luteinizing hormone and follicle stimulating hormone (P<0.05), but not so in testosterone compared to control (P>0.05). However, at 500 mg/kg there was decreased in the parameters especially in groups treated for 60 days. The results show that the extract did not significantly decrease sperm concentration and motility (slow progression). However, there was a significant decrease in rapid progression at all dose levels for both durations of treatment. Similarly there was no significant increase in death of sperm cells in treated groups compared to control (P>0.05). Results of the histological examinations of the testes, epididymis anterior pituitary and liver showed that the extract caused no visible serious morphological alterations on cells in rats treated with 125 and 250 mg/kg. The extract caused significant increase in testicular weights of rats in a dose-dependent manner (P<0.05). The fertility and reproductive performance tests showed that the extract at 250 mg/kg significantly increased the frequency of mounting, intromission and ejaculation (P<0.05). Similarly, the number of litters per female paired with male rats treated with the extract was found to be highest with the dose of 250 mg/kg for both the 20 and 60 days and lowest with 500 mg/kg. The extract caused a dose-dependent relaxation of an isolated corpus cavernosum smooth muscles of the rabbit. Results of the sperm viability analysis showed that the extract of G. kola did not cause significant decrease in viability compared with control. The antithrombotic test showed that the extract caused significant decrease in bleeding and clotting time in a dose-dependent manner in treated rats compared with control (P<0.05). Similarly the extract caused significant decrease in platelet counts in treated groups compared to control but not in any particular manner. The extract caused decrease in both the onset and duration of action in phenobarbitone-induced sleep in treated rats. Results of the effect of the extract on blood pressures showed that the extract caused a dose-dependent decrease in blood pressure. The phytochemical analysis of the extract revealed the presence of alkaloids, glycosides, saponins, tannins, flavonoids, carbohydrates and steroids while the elemental analysis revealed the presence of copper, iron, zinc, magnessium, potassium and sodium. The results when considered together suggest that the methanolic extract of Garcinia kola seed can improve male sexual performance and fertility at 125 and 250 mg/kg. However, consumption of it continuously for a long period and in high quantity of 500 mg/kg should be discouraged to avoid deleterious effects on spermatogenesis and sperm cells.