Echinacea purpurea Protects Against Restraint Stress-Induced Immunosuppression in BALB/c Mice

Echinacea purpurea has been widely used for the prevention and treatment of upper respiratory tract infections and the common cold. The restraint stress has been reported to suppress a broad spectrum of immune functions. The aim of this study was to investigate the protective effects of the pressed juice of E. purpurea (L.) Moench (EFLA^®894; Echinacea) against restraint stress-induced immunosuppression in BALB/c mice. Echinacea significantly normalized the restraint stress-induced reduction in splenocyte proliferation and splenic natural killer (NK) cell activity (P < .05). Echinacea treatment significantly increased the percentages of CD⁴⁺ and CD⁸⁺ T lymphocytes in the blood (P < .05). In addition, Echinacea restored serum cytokine levels, including interleukin-6 (IL-6), interleukin-10 (IL-10), and interleukin-17 (IL-17), as well as the mRNA expressions of these cytokines in spleen (P < .05). Our findings suggest that Echinacea might have beneficial effects on restraint stress-induced immunosuppression by increasing splenocyte proliferation and NK cell activity, while modulating T lymphocyte subsets and cytokine levels in the blood.