The Effect of Ethanolic Extract of Carica Papaya Black Seeds on Testosterone-induced Benign Prostate Hyperplasia in Rats

Abstract

Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a non-cancerous increase in size of the prostate gland. The use of traditional medicine in the treatment of various diseases has increased tremendously in global health because of their bioactive phytochemicals. One of such medicinal plant is Carica papaya. This research work was designed to investigate the effect of ethanol extract of Carica papaya black seeds in the treatment of testosterone-induced benign prostatic hyperplasia in rats. The extraction of 958 g of Carica papaya black seeds with ethanol produced an extract yield of 138.35 g which represented 14.44% of the starting plant material. The phytochemical screening of ethanol extract of Carica papaya black seeds revealed the presence of alkaloids (2.60 ± 0.12 mg/g), flavonoids (2.19 ± 0.17 mg/g), phenols (17.18 ± 0.07 mg/g), saponins (2.01 ± 0.13%), glycoside (4.53 ± 0.35 mg/g), tannins (7.90 ± 0.04%), cyanogenic glycosides (2.40 ± 0.03 mg/g) and steroids (0.074 ± 0.007 mg/g). The median lethal dose (LD50) study showed neither death nor signs of toxicity even at the highest dose of 5000 mg/kg body weight. The proximate analysis of Carica papaya black seeds revealed the presence of moisture (12.03 ± 0.72%), protein (21.4 ± 0.95%), fat (26.72 ± 2.32%), ash (3.81 ± 0.02%), fibre (9.40 ± 1.03%) and carbohydrate (26.9 ± 1.35%). The experimental animals were acclimatized for 7 days prior to the study and grouped into six (6) groups of five (5) rats each. BPH was induced by sub-cutaneous injection of testosterone 3 mg/kg b.w to the experimental rats for 28 days. Group 1; Normal control (no induction and untreated), Group 2; Untreated control (induced and untreated), Group 3; Standard control (induced and treated with finasteride 5 mg/kg b.w), Groups 4, 5 and 6 were induced and treated with 100, 200 and 400 mg/kg of the ethanol extract of Carica papaya black seeds. Each group was treated for 28 days and on the 29th day the animals were sacrificed using chloroform anaesthesia following an overnight fasting and weighing. Whole blood samples were collected by cardiac puncture, organs of interest (liver, testes, kidney and prostate) were dissected out and weighed and then prepared for biochemical assay using standard methods. The experimental results showed that prostate weight and prostate index of group 2 (1.99 ± 0.08 and 1.48 ± 0.01) increased significantly (p < 0.05) when compared to group 1 (1.38 ± 0.20 and 0.98 ± 0.15). Groups 3, 4 and 5 showed significant (p < 0.05) decrease in prostate weight and prostate index when compared to group 2. The levels of acid phosphatase (ACP), prostate specific antigen (PSA), dihydrotestosterone (DHT) and testosterone increased significantly (p < 0.05) in group 2 when compared to group 1. Group 6 showed significant (p < 0.05) decrease in ACP, PSA and DHT levels compared with group 2. Lipid profile test showed significant (p < 0.05) increase in total cholesterol (TC), triacylglycerol (TAG), and low density lipoprotein (LDL), and decrease in high density lipoprotein (HDL) levels in group 2 compared to group 1. Group 6 showed significant (p < 0.05) decrease in TC, TAG and LDL levels but increase in HDL level, compared to group 2. The results also showed a significant (p < 0.05) increase in the levels of liver function biomarkers: aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and kidney function biomarkers: creatinine and urea in group 2 when compared to group 1. Groups 4, 5 and 6 showed significantly (p < 0.05) decrease in the levels of these biomarkers when compared to group 2. The activities of catalase (CAT) and superoxide dismutase (SOD) in the liver, testes, kidney and prostate decreased significantly (p < 0.05) while malondialdehyde (MDA) level increased significantly (p < 0.05) in group 2 when compared to group 1. Groups 4, 5 and 6 showed significant (p < 0.05) increase in the activities of these antioxidant enzymes and decrease in MDA level when compared to group 2. From the study, ethanol extract of Carica papaya black seeds showed good ameliorative effect on the prostate and other vital organs of testosterone-induced BPH rats. Hence, it can be used in the treatment of testosterone-induced BPH.