A postulated role of garlic organosulfur compounds in prevention of valproic acid hepatotoxicity

Valproic acid (2-propyl-pentanoic acid, VPA) is well established as a first-line and widely used antiepileptic agent. VPA is well tolerated in most patients and has an impressive safety profile. VPA induced hepatotoxicity is rare, but often there is fatal complication of this drug and it is more frequent in children under 2 years of age and in those taking multiple drugs. Several findings showed that oxidative stress induced by reactive oxygen species (ROS) over production and/or compromised antioxidant capacity play an important role in the development of hepatotoxicity in VPA treated patients. Reduced glutathione (GSH) and its related enzymes are important cellular defense against oxidative stress in which VPA induced oxidative stress impairs their function in hepatocytes. Consequently any mechanism which removes ROS or prevents hepatic GSH depletion or induce activation and production of GSH dependent enzymes may provide protection for hepatotoxicity in VPA-treated patient. As garlic organosulfur compounds enhance cellular antioxidant activity by free radical scavenging and augmentation of endogenous antioxidants via prevention of GSH depletion and alteration of GSH dependent enzymes activity and/or their gene expression, we propose the hypothesis that garlic organosulfur compounds can prevent valproic acid hepatotoxicity.