(A) study of the effects of ginsenosides on atopy and their mechanism of action

Abstract

Ginsenosides, are known to have various highly pharmacological activities, such as anti-cancer, and anti-inflammatory effects. However, the search for the most effective ginsenosides against the pathogenesis of atopic dermatitis (AD) and the study of the effects of ginsenosides on specific cytokines involved in AD remain unclear. In this study, Rh2 was shown to exert the most effective anti inflammatory action on thymic stromal lymphopoietin (TSLP) and interleukin 8 in tumor necrosis factor-alpha and polyinosinic:polycytidylic acid induced normal human keratinocytes, by inhibiting proinflammatory cytokines at both protein and transcriptional levels. Concomitantly, Rh2 also efficiently alleviated 2,4-dinitrochlorobenzeneinduced AD-like skin symptoms when applied topically, including suppression of immune cell infiltration, cytokine expression and serum IgE levels in NC/Nga mice. In line with the in vitro results, Rh2 inhibited TSLP levels in AD mice via regulation of an underlying mechanism involving the nuclear factor κB pathways. In addition, with regard to immune cells, we showed that Rh2 suppressed not only the expression of TSLP, but the differentiation of naïve CD4+ Tcells into T helper type 2 (Th2) cells and their effector function in vitro. Collectively, our results indicated that Rh2 might be considered as a good therapeutic candidate for the alternative treatment of AD.