Immunomodulatory Effects of a Standardized Botanical Mixture Comprising Angelica gigas Roots and Pueraria lobata Flowers Through the TLR2/6 Pathway in RAW 264.7 Macrophages and Cyclophosphamide-Induced Immunosuppression Mice.

Abstract

Background: As the population ages, enhancing immune function is crucial to mitigating age-related physiological decline. Since immunostimulant drugs are known to have potential side effects, medicinal plants emerge as promising candidates offering a safer alternative. To leverage the advantages of medicinal plants with fewer side effects and develop a potent immune-enhancing agent, we investigated the efficacy of a novel immunomodulatory candidate derived from the combination of Angelica gigas and Pueraria lobata (CHL). Methods: In vitro, CHL was treated in RAW 264.7 macrophages at various time points, and the experiments conducted in the study were performed using ELISA, Western blot, and RT-qPCR analysis. In vivo, C57BL/6 mice were administrated CHL for 16 days (p.o.) and CTX on the three days (i.p.), and experiments were conducted with ELISA, western blot, RT-qPCR analysis, H&E staining, flow cytometry, gut microbiome, and correlation analysis. Results: In vitro, CHL has upregulated NO and cytokines expression, substantially enhancing the NF-κB and MAPK activation. Furthermore, CHL promoted the TAK1, TRAF6, and MyD88 via TLR2/6 signaling. In vivo, the CHL improved the reduced body weight and immune organs' indices and recovered various cytokines expression, NK cell cytotoxicity activity, and immune cell population. CHL also improved the histological structure and tight junction markers, mucin-2, and TLR2/6 in the intestines of CTX-induced mice. Conclusions: Overall, CHL demonstrated immunostimulatory potential by enhancing immune responses and restoring immune function, suggesting its promise as a safe and effective immune-enhancing agent.