Investigation of the immunomodulatory potential of oryzanol isolated from crude rice bran oil in experimental animal models.

Nutrition and nutritional status can influence the development, maintenance and optimal functioning of the immune system. Oryzanol (OZ), a commercially important bioactive phytochemical component of rice bran oil, has generated global interest on account of its several beneficial physiological effects on human health. The aim of the present investigation was to examine the effect of OZ, isolated from crude rice bran oil (cRBO), on the regulation of the immune response in experimental animal models. The isolated OZ was identified with respect to the standard by melting point determination, thin-layer chromatography (TLC), UV-visible spectrophotometry and high-performance liquid chromatography (HPLC). Cellular immunity in rats was assessed by carbon clearance assay, delayed-type hypersensitivity (DTH) response and cyclophosphamide-induced myelosuppression, whereas humoral immunity was analysed by haemagglutinating antibody (HA) titre assay. Oryzanol (25, 50 and 100 mg/kg, p.o.) evoked a significant increase in antibody titre values in the haemagglutination test and potentiated the delayed type hypersensitivity reaction induced by sheep red blood cells. It also significantly ameliorated myelosuppression in cyclophosphamide treated rats and showed an increase in phagocytic index in the carbon clearance assay. The findings from the study indicate that OZ possesses sufficient potential for augmenting immune activity by cellular and humoral mediated mechanisms.