Ajania purpurea Shih attenuates glutamate-induced damage by preventing oxidative stress and neuronal apoptosis via the Nrf2/HO-1 pathway in HT22 cells

Ajania purpurea Shih is a plant of the genus Ajania endemic to Tibet. As an ornamental plant, it has not been investigated for its pharmacological activity. In this study, HPLC analysis of 70% ethanol extracts of A. purpurea (EAPS) identified two major compounds, chlorogenic acid and piperine. We evaluated the cytoprotective activity and antioxidant effects of EAPS by examining the production of oxidative-stress-related mediators, including ROS, superoxide dismutase, and catalase, in glutamate-induced HT22 cells. JC-1 and TUNEL staining revealed that EAPS attenuated intracellular mitochondrial depolarization and subsequent apoptotic protein expression. Most importantly, EAPS promoted the nuclear translocation of Nrf2 and deliverance of HO-1 in HT22 cells. EAPS also inhibited glutamate-induced cytotoxicity and ROS production, which was partly changed by siRNA HO-1. These results intimate the effective cytoprotective and neuroprotective vitality of A. purpurea, peradventure via the adjustment of the Nrf2/HO-1 signaling pathway.