Prevention of oxidative stress in Chang liver cells by gallic acid-grafted-chitosans

Gallic acid-grafted-chitosans (GA-g-chitosans) were prepared according to our previous method, and the in vitro protective effect of the various GA-g-chitosans on tert-butyl hydroperoxide (t-BHP)-induced oxidative stress was investigated in Chang liver cells. Pretreatment of the GA-g-chitosans decreased cell damage induced by t-BHP in a dose-dependent manner. In addition, t-BHP-induced reactive oxygen species (ROS) generation and lipid peroxidation were inhibited by the GA-g-chitosans. Also, intracellular glutathione (GSH) was increased in the presence of the GA-g-chitosans. And GA-g-chitosan (I), which had the highest GA content, showed the highest activity among the tested compounds. Moreover, antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were decreased by t-BHP-induction., while GA-g-chitosan (I) pretreatment increased levels of CAT, SOD, and GPx. Overall, we demonstrated that GA-g-chitosans effectively attenuated the oxidative stress induced by t-BHP in Chang liver cells by inhibiting ROS generation, lipid peroxidation, and increasing levels of antioxidant enzymes.