ABSTRACT
Background: Theimmune system is intrinsic to health. Modulation of the immune responses to alleviate the diseases by using herbal plants has been of interest for many years. Diosgenin, a naturally occurring steroid saponin mainly present in the seeds of fenugreek (Trigonella foenum graecum)and in the root tubers of wild yams (Dioscorea vil-losa). Activation of specific and nonspecific immunity results in stimulation of immune response. Diosgenin has the positive effects on both specific and nonspecific immunity.Aim: To study the immunomodulatory activity of Diosgen-in in rats. Method: The suspension of Diosgenin wasgiven orally at the dosage level of 50, 100 and 150 mg/kg for 21 days in a rat. The immunomodulatory activity on specific and non-specific immunity was studied by haemagglutina-tion antibody (HA) titer, delayed type hypersensitivity (DTH) response and carbon clearance test. Immunosuppres-sion in a rat was induced by using Cyclophosphamide (100 mg/kg, p.o.). Sheep red blood cells (SRBCs) were used as antigen (0.1ml 20% SRBCs) in haemagglutinating antibody titer and delayed type hypersensitivity response methods. Result: Diosgenin exhibited significant increase in the production of antibody titer in response to SRBC antigen. A significant increase in both primary and secondary HA titer was observed in immunosuppressed group treated with Diosgenin when compared with negative control. A significant increase in the DTH response was observed in immu-nosuppressed animals treated with Diosgenin, pre-sensitized with SRBCs antigen. Diosgenin exhibited significant in-crease in phagocytic index against control group, indicating the stimulation of the reticuloendothelial system. Con-clusion: The study indicates that Diosgenin triggers stimulatory effect on specific and nonspecific immune response. The immunostimulant effect of Diosgenin could be attributed due to its saponin glycoside.