Effects of catechin on menadione-induced cytotoxicity / Widiayanna A. Rahim

The main objective of this study was to investigate the cytoprotective effects of catechin in menadione-induced cytotoxicity in both WRL 68 and Hep G2 cell lines. In order to achieve those objectives, the dose response relationships of menadione and catechin concentrations and their cytotoxic effects in each of the cell types were first explored. This allowed the determination of the median inhibitory concentration (IC50) for menadione and catechin. In order to assess cytoprotective effects of catechin, cells were then treated with menadione and catechin concomitantly for 24 h, after which cell viability was measured by the MTS assay. The IC50 values for menadione in WRL 68 and Hep G2 cell lines were 31.62±0.42µM and 3 I .62±0.86µM, respectively. IC50 values for catechin in WRL 68 and Hep G2 cell lines were 223.87±7.66 µMand 199.52±14.05 µM, respectively. In the cytoprotective studies, neither menadione ( I 5µM and 30 µM) nor catechin (30µM and 50µM) elicited a significant decrease in cell viability in WRL 68 cells. Thus, no cytoprotective effects by catechin against menadione induced cytotoxicity could be proven. A similar study in Hep G2 cells showed menadione ( I 5µM and 30µM) to elicit a significant decrease in cell viability compared to controls while catechin (30µM and 50µM) was without affect. Concomitant administration of menadione and catechin failed to show protection of Hep G2 cells against menadione's cytotoxicity by catechin. In summary, dose-response relationships for the cytotoxicity of menadione and catechin were obtained in WRI 68 and Hep G2 cells. Catechin (30µM and 50µM) failed to show cytoprotection of these cell lines against menadione's ( I 5µM and 30µM) cytotoxicity.