Mitigation of aflatoxin B1- and sodium arsenite-induced cytotoxicities in HUC-PC urinary bladder cells by curcumin and Khaya senegalensis.

Background: Concomitant exposure to environmental/occupational toxicants such as aflatoxin B₁ (AFB₁) and arsenic in some regions of the world has been well reported. Therefore, this calls for the assessment of the efficacy of agents such as phytochemicals, which are already known for their ethno-medicinal uses in prophylaxis/remediation. We investigated the possible cytotoxic bio-interactions between AFB₁ and sodium arsenite (SA) in urinary bladder cells. We also assessed the cytoprotective effects of curcumin and the ethanol stem bark extract of Khaya senegalensis (K2S). Methods: The cells were exposed to graded levels of AFB₁, SA, curcumin, and K2S for 24, 48, and 72 h. Subsequently, using optimum toxic concentrations of AFB₁ and SA, respectively, the influence of non-toxic levels of curcumin and/or K2S was tested on exposure of the cells to AFB₁ and/or SA. Hoechst 33342/propidium iodide staining technique was used to determine the end-points due to cytotoxicity with changes in adenosine triphosphate (ATP) levels determined using Promega's CellTiter-Glo luminescent assay. Results: Co-treatment of the cells with AFB₁ and SA resulted in synergy in cytotoxic effects. Cytotoxicity was reduced by 3.5- and 2.9-fold by pre-treatment of the cells with curcumin and K2S before treatment with AFB₁, while post-treatment resulted in 1.1- and 2.6-fold reduction, respectively. Pre-exposure of the cells with curcumin and K2S before treatment with SA ameliorated cytotoxicity by 3.8- and 3.0-fold, but post-treatment caused a 1.2- and 1.3-fold reduction, respectively. Conclusions: Pre-treatment of the cells with either curcumin or K2S exhibited cytoprotective effects by ameliorating AFB₁- and SA-induced cytotoxicity with inferred tendencies to prevent carcinogenesis. [ABSTRACT FROM AUTHOR]