PROTECTIVE ROLE OF KOLAVIRON, A BIFLAVONOID FROM Garcinia kola HECKEL SEEDS ON THE PROSTATE OF DIABETES MELLITUS RATS

Abstract

Diabetes mellitus (DM) and Benign prostatic hyperplasia (BPH) is a comorbidity of elderly men and is associated with complications such as infertility. Male infertility caused by this comorbidity has also been linked to poor semen quality. The role of prostatic fluid in the maintenance of semen quality is crucial. Kolaviron (KV), a biflavonoid from Garcinia kola (GK) seeds, has been reported to promote fertility in male DM rats. However, the effect of KV on comorbidity-induced prostate impairment is unknown. Therefore, this study was designed to investigate biochemical and structural changes in prostate of DM and BPH rats, and the protective role of KV.

Garcinia kola seeds were obtained commercially, authenticated at Department of Botany Herbarium, University of Ibadan (UI-00138/01). Powdered GK seeds was extracted in soxhlet using methanol. The methanol extract was partitioned with chloroform and water to obtain a golden colour fraction called Kolaviron. Twenty-six male Wistar rats were assigned into three groups: Control (n=10), 3 months DM (3MDM, n=8) and 5 months DM (5MDM, n=8). Diabetes mellitus was induced by a single administration of Streptozotocin intraperitoneally (35 mg/kg). Rats were sacrificed at 3 and 5 months after DM and, blood and prostate were obtained for analysis. Another twenty rats were assigned into four groups (n=5): BPH control, BPH+DM, BPH+DM+KV (200 mg/kg) and BPH+DM+MET (Metformin, 200 mg/kg). The BPH was induced by daily administration of testosterone propionate (TP) intraperitoneally (3 mg/kg) to the castrated rats for 28 days. Biochemical assays were determined, spectrophotometrically. Luteinizing and Follicle stimulating hormones (LH and FSH) and testosterone were estimated using ELISA, while zinc and bicarbonate were estimated using Atomic Absorption Spectrophotometry. Micronucleated polychromatic erythrocytes (mnPCEs) frequencies, histology and expressions of B-cell lymphoma (Bcl-2) and ki67 were determined using standard methods. Data were analysed using ANOVA at α0.05.

The FBS, HbA1c and mnPCE were increased in 3MDM by 4.0, 2.0 and 2.0 folds, and in 5MDM by 6.0, 3.0 and 3.0 folds, respectively. Activities of ALT and AST were increased with concomitant increase in urea, creatinine and total bilirubin in 3 and 5MDM. Total ACP decreased in 3MDM and 5MDM by 32.4% and 72.2%, respectively, while prostatic ACP decreased by 47.6% in 5MDM. Prostatic Zinc and bicarbonate increased in 3MDM by 1.7 and 1.9 folds, and in 5MDM by 5.8 and 1.7 folds, respectively. In 3MDM and 5MDM, levels of LH, FSH, testosterone and activities of antioxidant enzymes decreased, while LPO level increased relative to control. In 3MDM and 5MDM, mild expression of Bcl-2 and Ki67 were observed. In BPH+DM, mnPCE increased relative to BPH control. Treatment with KV and MET decreased mnPCE relative to BPH+DM. Serum urea, total bilirubin and total ACP increased in BPH+DM by 252.1%, 48.7% and 57.2%, respectively, while total bilirubin and total ACP decreased by 69.3% and 54.4%, respectively in BPH+DM+MET. In BPH+DM, serum ALT, AST and prostatic ALP increased, relative to BPH control, while treatment with KV and MET decreased these biochemical parameters. Histopathology of prostate revealed hyperplasia and intra-luminal budding of epithelia in BPH+DM which were attenuated by KV.

The biochemical and structural changes observed in the prostate of diabetes mellitus rats and in comorbidity with benign prostate hyperplasia were attenuated by kolaviron.