Effect of Ocimum sanctum on the development of protective immunity against Salmonella typhimurium infection through cytokines

ObjectiveTo investigate the protective role of Ocimum sanctum (O. sanctum) leaves against Salmonella typhimurium(S. typhimurium) infection in rats by inducing TNF-α, IFN-γ& IL-2 cytokines.MethodsWistar albino rats were fed with aqueous extract of O. sanctum leaves using 250 mg/kg body weight dose once a day for 20 consecutive days. Control rats were fed with placebo. Rats were infected with LD 50 dose of S. typhimurium infection and monitored for their survival. Bacterial blood burden in both the groups was compared and numbers of activated peritoneal macrophages were counted. Concentration of TNF-α, IFN-γ and IL-2 cytokines in serum during different time intervals was assayed by sandwich ELISA.ResultsRats of control group showed a high mortality rate and had higher bacterial blood burden when compared with O. sanctum extract fed rats. There was a significant increase in the number of S. typhimurium engulfed peritoneal macrophages in the peritoneal fluid of O. sanctum fed animals. The protective control against bacterial infection in O. sanctum fed rats was associated with elevated level of TNF-α, IFN-γ and IL-2 cytokines in serum.ConclusionsThese findings suggest that orally administered O. sanctum leaves extract effectively enhanced activation in macrophage and lymphocytes, depicted by the elevated serum concentration of TNF-α, IFN-γ and IL-2 cytokines, leading to induce a protective resistance against Salmonella typhimurium infection.