Effects of Viola yedoensis Makino anti-itching compound on degranulation and cytokine generation in RBL-2H3 mast cells

Ethnopharmacological relevance: The Chinese herb compound prescription Viola yedoensis Makino Anti itching Compound (VYAC), which consists of Viola yedoensis Makino, herb, Sophora flavescens Aiton, root, and Dictamnus dasycarpus Turcz, root and rhizome, has been traditionally used to treat various skin allergic inflammatory diseases in clinic. Aim of the study: The aim of this study is to investigate the effects of VYAC on degranulation and to determine its anti-inflammatory mechanism in RBL-2H3 mast cells. Materials and methods: VYAC was extracted with water-coction extraction (Shufen et al., 2012). The aqueous extracts were concentrated in vacuum under reduced pressure and lyophilized using a freeze dryer, and lyophilized powder was obtained. MIT was used to evaluate the cytotoxic of VYAC on RBL-2H3 cells. Degranulation was carried out with RBL-2H3 cell model, which was stimulated with A23187 plus PMA. beta-Hexosaminidase and histamine were measured to evaluate degranulation. The mRNA levels of inflammation cytokines (IL-1 beta, TNF-alpha, IL-6, and iNOS) were investigated by RT-PCR to explain the anti-inflammatory mechanism of VYAC. Results: VYAC did not show cytotoxic effect on RBL-2H3 cells in the range of 25-400 mu g/mL. A higher dose of VYAC (800 mu g/mL) showed significant cytotoxicity (P < 0.05). VYAC could significantly inhibit beta-hexosaminidase and histamine release when treated with 100, 200, and 400 mu g/mL (P < 0.05), but could not significantly inhibit P-Hexosaminidase and histamine release when treated with 25 and 50 mu g/mL (p > 0.05). The mRNA levels of inflammatory cytokines (TNF-alpha, IL-1 beta, IL-6, and iNOS) could significantly decrease when treated with 200 and 400 mu g/mL (P < 0.05) of VYAC, which were associated with the development of inflammation. Conclusions: Results showed that VYAC inhibited beta-hexosaminidase and histamine release, which was inhibit A23187 plus PMA stimulated RBL-2H3 cell degranulation and downregulated inflammatory cytokines (IL-1 beta, TNF-alpha, IL-6, and iNOS) expression to block inflammatory development. (C) 2016 Elsevier Ireland Ltd. All rights reserved.