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

摘要

AIM:To evaluate the protective effect of 2'-p-hydroxy benzoylmussaenosidic acid [negundoside(NG) ,against carbon tetrachloride(CCl4) -induced toxicity in HuH-7 cells. METHODS:CCl4 is a well characterized hepatotoxin,and inducer of cytochrome P450 2E1(CYP2E1) -mediated oxidative stress. In addition,lipid peroxidation and accumulation of intracellular calcium are important steps in the pathway involved in CCl4 toxicity. Liver cells(HuH-7) were treated with CCl4,and the mechanism of the cytoprotective effect of NG was assessed. Silymarin,a known hepatoprotective drug,was used as control. RESULTS:NG protected HuH-7 cells against CCl4 toxicity and loss of viability without modulating CYP2E1 activity. Prevention of CCl4 toxicity was associated with a reduction in oxidative damage as reflected by decreased generation of reactive oxygen species(ROS) ,a decrease in lipid peroxidation and accumulation of intracellular Ca2+ levels and maintenance of intracellular glutathione homeostasis. Decreased mitochondrial membranepotential(MMP) ,induction of caspases mediated DNA fragmentation and cell cycle arrest,as a result of CCl4 treatment,were also blocked by NG. The protection afforded by NG seemed to be mediated by activation of cyclic adenosine monophosphate(cAMP) synthesis and inhibition of phospholipases(cPLA2) . CONCLUSION:NG exerts a protective effect on CYP2E1-dependent CCl4 toxicity via inhibition of lipid peroxidation,followed by an improved intracellular calcium homeostasis and inhibition of Ca2+-dependent proteases.