Immuno-modulatory effects of methanolic extract of Ferula szowitsiana on isolated human Th1/Th2/Treg cytokines levels, and their genes expression and nitric oxide production.

Abstract Background Anti-inflammatory and anti-oxidants activities of Ferula szowitsiana L. (F. szowitsiana) were shown in ancient texts and assayed by modern studies. However, immunomodulatory properties of the plant are poorly understood. Methods The effects of F. szowitsiana extract (10, 40 and 160 µg/ml), dexamethasone and vehicle were investigated on nitric oxide (NO) level, cell proliferation, and cytokines (IL-4, IL10 and IFN-γ) expression at gene and protein levels in non-stimulated and phytohaemagglutinin-stimulated human lymphocytes (n = 15 in each group). Results Cell proliferation, cytokines secretion, NO production and levels of genes expression were significantly inhibited but IFN-γ/IL-4 and IL-10/IL-4 ratios (T helper 1/Th2 and Treg/Th2 balances respectively) were increased by dexamethasone and all three concentrations of the extract compared to control group in stimulated lymphocytes (P  Conclusion The extract of F. szowitsiana concentration-dependently decreased NO level but increased Th1/Th2 and Treg/Th2 ratios toward Th1 and Treg. These results suggest the therapeutic potential of the plant’s extract in inflammatory diseases with dominant Th2 polarization such as asthma or cancers.