In vitro modulation of TH1 and TH2 cytokine expression by edible tuber of Dioscorea alata and study of correlation patterns of the cytokine expression

The underground tuber of Dioscorea alata is a palatable food and is also claimed to have therapeutic effects. Various groups of researchers demonstrated different activities of this tuber such as antioxidant, hepatoprotective, anti-ulcer and anti-diabetic activities. Therefore, the aim of the present study was to evaluate the immunomodulatory potentialities of 70% hydro-methanolic extract of D. alata underground tubers by investigating different parameters like the expression of interferon gamma (IFN-γ), interleukin (IL)-2, IL-4 and IL-10, in addition to its effect on the proliferation of murine splenic T-lymphocytes in vitro. Results demonstrated that D. alata can actively polarize the TH0 lymphocyte population towards the expression of TH1 immune response by up-regulating the IFN-γ and IL-2 expression and down-regulating the IL-4 and IL-10 expression. The tuber extract also proved to possess mitogenic activity as evidenced by the proliferation of lymphocytes in vitro.