Human epithelial carcinoma cytotoxicity and inhibition of DMBA/TPA induced squamous cell carcinoma in Balb/c mice by Acacia catechu heartwood.

OBJECTIVES: Acacia catechu heartwood contains significant amounts of polyphenolic compounds that exhibit powerful antioxidant activity. The purpose of this study was to evaluate the cytotoxicity of A. catechu heartwood extracts in a human epithelial carcinoma cell line (A431) and antitumour activity against DMBA/TPA induced squamous cell carcinoma in Balb/c mice. METHODS: Various extracts, including aqueous, ethyl acetate, chloroform and n-hexane, were tested for cytotoxic properties on a human epithelial carcinoma cell line (A431) by using MTT, sulforhodamine B and lactate dehydrogenase leakage assays. The standardized A. catechu heartwood aqueous extract (AQCE) was further evaluated for antitumour activity against 7,12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) induced skin carcinoma in Balb/c mice. KEY FINDINGS: The results showed that administration of AQCE showed a dose-dependent growth inhibition response, with an IC50 value of 78.56 µg/ml. Tumour incidence was significantly decreased (P < 0.001) to 30% with AQCE compared with 100% in the DMBA/TPA group. The AQCE was also found to significantly upregulate different antioxidant enzymes in skin and liver tissue. CONCLUSIONS: The results suggest that AQCE may exert its chemopreventive activity by acting as an antioxidant.