Immunomodulatory Effect of Methanolic Extract and Ethyl Acetate Fraction of Bengkoang (Pachyrhizus erosus (L.) Urban) Tuber in Mice

Background: Recently, interest in the use of herbal medicine that can modulate the immune system is increasing in the pandemic situation. One plant that can be developed as an immunomodulator is bengkoang (Pachyrhizus erosus (L.) Urban). Objectives: To evaluate the immunomodulatory effect of a methanolic extract of bengkoang (MEB) and the ethyl acetate fraction of bengkoang (EAFB) in mice induced by the hepatitis B vaccine. Materilas and Methods: Thirty healthy male mice were divided into six groups namely, control, standard levamisole, MEB (100 and 200 mg/kg BW), and EAFB at 100 and 200 mg/kg body weight (BW). The treatments were given for 18 days, and hepatitis B vaccine was injected intraperitoneally twice during the treatment. Assessment of the immunomodulatory effect was carried out against nonspecific and specific immune response parameters. Results: The MEB and EAFB could significantly increase phagocytic capacity, the spleen index, and lymphocyte proliferation. MEB stimulated IgG production, while EAFB, 100 mg/kg BW suppressed immunoglobulin G (IgG) production; otherwise, at the higher dose, EAFB increased IgG production. EAFB also increases nitric oxide production, while MEB had no effect. The higher dose of MEB tended to increase tumor necrosis factor (TNF)-α levels and decrease interleukin (IL)-10, while EAFB tended to decrease TNF-α and increase IL-10, but these changes were not significant. Conclusion: Based on this study, MEB and EAFB could increase the innate immune response and stimulate the humoral immune response but had no effect on cytokine production, which may have potential usefulness of bengkoang to treat immunomodulatory-related disease.