Antioxidant effects of Cirsium japonicum var. maackii on oxidative stress in C6 glial cells and mice

Abstract

We investigated the effects of Cirsium japonicum var. maackii (CJM) against oxidative stressinduced C6 glial cells and cognitive impairment in mice. To evaluate the anti-oxidative effect of the extract and fractions from CJM, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), reactive oxygen species (ROS), and nitric oxide (NO) assays were conducted in H2O2-treated C6 glial cells. Furthermore, we identified the protective mechanisms of CJM with a scopolamine-treated mice model. The results revealed that H2O2 decreased the cell viability in C6 glial cells, indicating that H2O2 induced oxidative stress in glial cells. However, CJM fractions significantly increased cell viability in H2O2-treated C6 glial cells, which suggested that CJM protected against oxidative stress. CJM extract and fractions also reduced ROS and NO production, which were increased by H2O2 in C6 glial cells. In particular, the EtOAc fraction from CJM (EACJM) effectively protected against oxidative stress by increasing the cell viability and decreasing ROS and NO. Therefore, we carried out further in vivo experiments with EACJM. Scopolamine caused increases of ROS, thiobarbituric acid reactive substances (TBARS), and NO production. However, EACJM effectively alleviated ROS, TBARS, and NO levels compared to scopolamine-injected mice. In addition, EACJM up-regulated protein expressions of superoxide dismutase and glutathione peroxidase, indicating that EACJM enhanced the antioxidative system. Our results demonstrated that CJM had protective effects against oxidative stress in glial cells and memory dysfunction in mice. Based on these results, we propose that CJM could be a potential AD preventive and therapeutic agent.