Curcuma longa and colon cancer: Evidence and mechanisms

The present study aims to evaluate the role of Curcuma longa (turmeric) methanolic extract against colon cancer- induced in rats. Forty male rats were classified into 5 groups as follows: Group (1) control. Groups from (2) to (5) intrarectally injected with N-methylnitrosourea in a dose of 2 mg dissolved in 0.5 ml water/rat three times weekly for five weeks for induction of colon cancer and group (2) left untreated (cancer group); group (3) intraperitoneally injected with 5-fluorouracil and groups (4 and 5) treated orally with 437.5 mg/kg b.wt and 875 mg/kg b.wt of turmeric extract respectively daily for four months. Histological investigation of colon tissue was done. Colon β-catenin and K-ras genes expression was detected by RT-PCR. Immunohistochemical technique was applied used for estimation of colon COX-2 and survivin expression. Plasma TGF-α, Bcl-2 and serum CEA and CCSA-4 levels were assayed using ELISA procedure. Histopathological investigation of colon tissue sections in cancer group showed dysplasia and anaplasis in the lining epithelial cells of the glandular structure. Additionally, cancer group declared significant increase in the expression levels of β-catenin and K-ras genes in colon tissue. Furthermore, colon cancer induced-rats demonstrated significant increase in colon COX-2 and survivin expression in colon tissue associated with significant elevation in the circulating levels of all studied biochemical markers. In the contrary, treatment with 5-fluorouracil or turmeric extract showed marked improvement in the histological structure of colon tissue. As well as, significant decrease in the expression levels of β-catenin and K-ras genes was detected. Also, all treated groups exhibited marked decrease in COX-2 and survivin expression in colon tissue accompanied with significant reduction in the circulating levels of the all studied biomarkers. Thus, it could be concluded that Curcuma longa methanolic extract has a promising therapeutic role against colon cancer induced in rats, as it has anti-inflammatory, anti-proliferation and apoptotic effects.