Ajania purpurea Extract Attenuates LPS-Induced Inflammation in RAW264.7 Cells and Peritonitis Mice

Macrophages have important roles in the progression of inflammation. Ajania purpurea Shih. is a member of the Ajania Poljakor family that grows in Tibet (China). Extracts from plants in this genus have anti-bacterial and anti-inflammatory properties. However, there are few reports on the activity and mechanism of Ajania purpurea. Here, we confirmed the anti-inflammatory effect of Ajania purpurea Shih. ethanol extract (EAPS) by examining the levels of inflammatory factors in a mouse model of peritonitis and RAW264.7 cells. The main components of EAPS detected by LC-MS analysis included piperine and chlorogenic acid. In particular, in lipopolysaccharide (LPS)-induced RAW264.7 cells, EAPS inhibited the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-induced RAW264.7 cells, lowered the levels of nitric oxide (NO) and prostaglandin E2 (PGE₂), as well as the release of inflammatory factors such as tumor necrosis factor-alpha (TNF-α) and pro-inflammatory cytokines such as interleukin (IL)-1β and IL-6. In addition, Western blot analysis and immunofluorescence staining verified that EAPS inhibited the activity of the nuclear factor-kappaB (NF-κB) pathway by reducing the nuclear translocation of the p65 subunit. Furthermore, in a mouse model of peritonitis, EAPS inhibited the release of inflammatory factors, as well as the recruitment of immune cells including neutrophils and macrophages. These findings indicated that EAPS suppressed LPS-induced inflammation via inhibiting the NF-κB pathway in RAW264.7 cells and mice with peritonitis. Thus, EAPS may be a viable therapeutic method for the treatment of inflammation and related disorders.