Echinacea purpurea extract enhances natural killer cell activity in vivo by upregulating MHC II and Th1-type CD4⁺ T cell responses.

There are a number of factors that cause immune system disruption, including infection caused by foreign antigens and decreased immunity due to excessive exercise, and public interest in improving immunity is growing. In this study, we investigate the immunomodulatory effects of Echinacea purpurea (E) extract in C57BL/6N mice that were exposed to a forced swimming exercise. There were six experimental groups as follows: wild-type, forced swimming exercise control, positive control (red ginseng, 300 mg/kg), and E (50, 100, and 200 mg/kg b.w.) groups. The mice were administered the E extract for 2 weeks. We detected chicoric acid, the active substance of E, through high-performance liquid chromatography and evaluated changes in the following laboratory values in response to forced swimming exercise using flow cytometry and ELISA: the major histocompatibility complex (MHC), CD4⁺ and CD8⁺ T cells, Th1 and Th2 cytokines, natural killer (NK) cell activity, and number of leukocytes....