Immune enhancement effect of an herb complex extract through the activation of natural killer cells and the regulation of cytokine levels in a cyclophosphamide-induced immunosuppression rat model

Objective: To investigate the effects of a herb complex extract(HCE) prepared from Cornus officinalis Sieb. Et Zucc., Eriobotrya japonica Lindley, and olive leaves on immune response of mouse spleen NK cells in vitro and in vivo analysis. Methods: The activity of natural killer(NK) cells was measured in splenocytes and YAC-1 cells. Mice were immunosuppressed using cyclophosphamide(5 mg/kg body weight). Three different doses of HCE(200, 400, and 800 mg/kg body weight) and red ginseng extract(800 mg/kg body weight) which was used as standard immunomodulatory herb were administered orally for 4 weeks. The body weight, dietary, water intake, organs(liver, thymus, and spleen) weight, completed blood count, and cytokines(tumor necrosis factor alpha, interferon gamma, and interleukin-2) production was measured. Results: At the maximum concentration of HCE, the activity of NK cells was increased by 48.5%. HCE increased liver, spleen, and thymus weights without altering numbers of white blood cells, lymphocytes, and neutrophils in a cyclophosphamide-induced immunosuppression rat model. However, HCE recovered the inhibited cytokine expression; HCE(800 mg/kg) increased cytokines levels. The results indicate the immune enhancement potential of this HCE. Conclusion: The HCE enhances immunity by increasing NK cell activity, regulating cytokine levels, and maintaining spleen weight. Therefore, it may be used as a potential immunity enhancer.