Faloak (Sterculia quadrifida R.Br) is widely used as traditional medicine in Indonesia to improve stamina (reduce tiredness for heavy workers). However, no scientific reports so far on the immunomodulatory effect. The aim of this study was to determine the effect of the bark of faloak as immunomodulatory agents by evaluating their effect on BALB/c mice lymphocytes proliferation, the activity of macrophage, nitric oxide production and the immunoglobulin G titer by in vivo techniques.Decoction of the faloak bark was used for the in vivo assay. BALB/c mice were divided into 5 dose groups, each consisting of 5 mice. One group was chosen as the baseline, 3 groups were used for the group treated with the test substance at doses of 7.5, 11.75 and 17.5 g kg-1 of body weight of mice (p.o) and a positive control group was treated with Phyllanthus niruri Linn. (PN) extract (Stimuno®) 0.585 g kg-1 b.wt., (p.o). The test samples were given every day. All mice were induced by hepatitis B vaccine at day 7 and 14. The activity of in vivo assay was determined at day 19. The activity of immunomodulatory effect is expressed in phagocytic capacity, phagocytosis index, nitric oxide, OD of lymphocyte proliferation and IgG titers.The macrophage phagocytic capacity and phagocytosis index were significantly increased (p<0.05), nitric oxide production were altered significantly (p<0.05), but OD of lymphocyte proliferation and production of IgG titers were unchanged (p>0.05).This study showed that the faloak bark could increase the macrophages phagocytic activity, but no effect on lymphocyte cells and therefore did not influence the adaptive immune response.
