Abstract

The effects of dietary curcumin on three major types of immune function were examined in rats. Antibody (IgG) production, delayed-type hypersensitivity and natural killer cell activity were evaluated after 5 weeks of dietary exposure to 1, 20 or 40 mg/kg curcumin. The highest dose of curcumin significantly enhanced IgG levels. Rats receiving lower dietary concentrations (1 or 20 mg/kg) of curcumin were not different in IgG production from rats receiving no curcumin in their diet. Neither delayed-type hypersensitivity nor natural killer cell activity was different from control values at any dietary concentration of curcumin. In vitro incubation of YAC-1 and EL4 tumor cells and normal splenocytes in varying concentrations of curcumin for varying times revealed differences between cell types in curcumin's effects on cell proliferation and viability. No cytotoxic effect was seen in EL4 cells at 12S μg/ml curcumin at 4, 24 and 48 hrs incubations, however, cell proliferation was reduced by almost 50 % at 24 hrs. YAC-1 cell viability and cell numbers were diminished at longer incubations. A lower curcumin concentration (1.25 μg/ml) enhanced cell growth in the YAC-1 cells at 24 and 48 hr. This enhancement was not seen in spleen or EL4 cells.