Effect of kolaviron, a biflavonoid complex from Garcinia kola seeds, on the antioxidant, hormonal and spermatogenic indices of diabetic male rats

The antihyperglycaemic effect of kolaviron (KV), a biflavonoid from Garcinia kola has been established in previous studies. In this study, we investigated the effect of KV (200 mg kg(-1)) on the antioxidant, hormonal and spermatogenic indices of alloxan-diabetic male rats, and metformin hydrochloride (MET) (30 mg kg(-1)) served as standard drug. The results showed that KV and MET significantly (P < 0.05) decreased the fasting blood glucose of the diabetic rats. Also, untreated and MET-treated diabetic groups had significantly (P < 0.05) lower body-weight gain and relative weights of testes. In addition, epididymal sperm abnormalities were increased, whereas sperm count, motility, testicular protein and sialic acid were decreased in untreated diabetic group. Also, antioxidant parameters, reduced glutathione, catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase were significantly (P < 0.05) reduced in the testes with a concomitant increase in lipid peroxidation in untreated diabetic group. Furthermore, untreated diabetic group had significantly (P < 0.05) lower levels of testosterone, luteinising and follicle-stimulating hormones relative to controls. Treatment with KV restored the relative weights of testes, activities of antioxidant enzymes, sperm and hormonal indices of the diabetic animals. This study demonstrated the role of KV to promote fertility in diabetic male rats by enhancing the hormonal and antioxidant status of the rats.