Anti-cancer potential of Tetracarpidium conophorum (African walnut) seed oil on prostate carcinogenesis

Abstract

Prostate cancer is the leading cause of mortality in men worldwide, and dietary fat influence its incidence. This study investigated the effect of feeding Tetracarpidium conophorum seed oil (TCSO) on 3-methylcholanthrene (MCA) induced prostate cancer in Wistar rats, the expression of cyclooxygenase2 (COX-2) and peroxisome proliferator activated receptor gamma (PPAR-ɣ) in the prostatic tissues. The TCSO was extracted with n-hexane in a Soxhlet apparatus and characterized by gas chromatography. Forty-eight male wistar rats (4 weeks old) were divided into three groups of 16 rats each and fed for 12 weeks. Group A and B animals were fed with diet containing TCSO extract. The animals in Groups A and C received intraperitoneally a dose of MCA (150 mg/kg) after 30 days of feeding. Groups A and B rats were fed with diet containing 10% of extracted TCSO throughout the period of the experiment. Results showed that COX-2 activity significantly decreased (p < 0.05) in Group A (0.71±0.07) and B (0.60±0.05) when compared with Group C (1.17±0.10) with increased COX-2 expression. PPAR-gamma activity was significantly increased (p < 0.05) in Group A (1.89±0.13) and B (2.30±0.15) in comparison with Group C (1.16±0.10) which has the lowest PPAR-gamma expression. TCSO extract delayed latency period in Group A where lumps were observed after 4 weeks of 3-methylcholanthrene induction in comparison with Group C where lumps were observed in less than 2 weeks of MCA induction. Gammalinoleic acid, docosahexaenoic acid and myristoleic acid were higher in the liver cell membrane of animals in Group A compared to animals in Group C. This work therefore showed that TCSO contains bioactive components that may oppose prostate carcinogenesis induced by MCA.