Negundoside, an iridiod glycoside from leaves of Vitex negundo, protects human liver cells against calcium-mediated toxicity induced by carbon tetrachloride

Figure 2 Cytotoxicity profile of CCl₄ and protective effect of NG and silymarin on CCl₄-induced inhibition of cellular proliferation in HuH-7 cells. For cell proliferation assay, HuH-7 cells grown in 24-well culture plate were incubated with indicated concentrations of test materials. Cell proliferation was assessed by MTT reduction assay. A, B: Represents inhibition of cell proliferation by CCl₄ and test materials (NG and silymarin); C: Represents protection of NG and silymarin, against CCl₄ induced inhibition of cell proliferation. HuH-7 cells were treated with various concentrations of NG and silymarin (5 to 100 mg/L) 1 h before treatment with CCl₄ for 24 h and the cell proliferation was determined by MTT reduction assay. Control wells received medium containing DMSO (< 0.2 mL/L). The % cell cytoxicity, % viability and % cytoprotection was calculated as, % Cytotoxicity = (Control - Test)/Control x 100, % Cell viability = % Cytotoxicity - 100, % Cytoprotection = 100 - (Treated - Control)/(CCl₄ - Control) x 100. Data are mean ± SD (n = 8) and representative of one of three similar experiments and statistically significant P values: ^bP < 0.01; ^dP < 0.001; ^aP < 0.02; ^cP < 0.05; NS: Non-significant, CCl₄ treated vs control cells; CCl₄ + LIV-1/silymarin vs CCl₄ treated cells.