Immunoenhancing Effects of Jeju Agastache rugosa Extracts on NK Cell Activity and Lymphocyte Proliferation in Cyclophosphamide-Induced Immunosuppression

Background/objectives: This study evaluated the immunoenhancing effects of Agastache rugosa extract in a cyclophosphamide-induced immunosuppressed mouse model. Methods: Jeju A. rugosa was processed via hot water extraction and 20% ethanol extraction. For immunosuppression induction, 7-week-old male BALB/c mice received intraperitoneal CPA injections (150 mg/kg, day −3; 110 mg/kg, day −1), followed by oral administration of hot water extract (ARE-W) and ethanol extract (ARE-E) at 100 and 300 mg/kg for 14 days. Oral administration of ARE-W and ARE-E was started on day 0, immediately following the final CPA injection on day −1. Immune function was assessed through body weight changes, spleen weight, NK cell activity, IFN-γ production, and splenic lymphocyte proliferation. Results: Results demonstrated that CPA treatment induced comprehensive immune dysfunction, while A. rugosa extracts significantly ameliorated these immunosuppressive conditions. Notably, ARE-W (300 mg/kg) significantly enhanced NK cell cytotoxicity against tumor cells and IFN-γ production compared to the CPA group, and effectively restored spleen weight and lymphocyte proliferation. ARE-E also exhibited dose-dependent immune function recovery; however, ARE-W showed superior efficacy across most immune parameters. Conclusions: These findings suggest that A. rugosa extract, particularly ARE-W, effectively restores immune function in immunosuppressed conditions, indicating potential application as a natural functional material for ameliorating immunosuppression caused by cancer treatment or immune diseases.