Immune-enhancing Effect of Bengkoang (Pachyrhizus erosus (l.) Urban) Fiber Fractions on Mouse Peritoneal Macrophages, Lymphocytes, and Cytokines

Background: This study was conducted to evaluate the immunomodulatory effects of bengkoang (Pachyrhizus erosus [L.] Urban) fiber extract (BFE) fraction on mouse peritoneal macrophages, lymphocytes, and cytokines. Materials and Methods: BFE was prepared by heat-extraction from the bengkoang fiber in distilled water at 121°C for 20 min. Fraction of BFE including BEF-A, BEF-B, BEF-D, and BEF-E were prepared by precipitation method with cold ethanol and potassium hydroxide. The phagocytic activity of macrophages was observed by a phagocytosis assay using mouse macrophages. The lymphocyte proliferation assay was performed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and measuring the absorbance at 550 nm. Also, the production of cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 was determined. Results: The BFE enhanced the phagocytic activity by increasing the phagocytic index and capacity of mouse peritoneal macrophages. The phagocytic capacity of mouse peritoneal macrophages was significantly increased after the treatment of BFE, BFE-B, and BFE-E compared with control. The fractions BFE-A, BFE-B, BFE-D, BFE-E, and pectin could stimulate phagocytic activity by increasing the phagocytic index. There were no significant differences after treatment with fiber fractions in enhancing lymphocyte proliferation, but pectin could stimulate the lymphocyte proliferation. Also, the fraction of BFE-A could enhance TNF-α and IL-10 production. After treatment with BFE-B, there were increases in TNF-α and IL-6 production but decreases in IL-10 production. The fraction of BFE-D could also stimulate TNF-α production, and BFE-E could reduce IL-10 production. Conclusion: The fiber fractions of bengkoang showed an immune-enhancing effect, stimulated both TNF-α and IL-6 production, and suppressed IL-10.