Severe asthma is a chronic inflammatory disease that is not sensitive to glucocorticoid treatment.In the pathogenesis of severe asthma,T helper cell 17(Th 17)and interleukin 17(IL-17)play an important role,mainly by aggregating the infiltration of neutrophil to aggravate the severity of asthma.Methyl-CpG-binding protein 2(MBD2)plays an important role in the differentiation of Th 17 cells from naive CD4+T cells,positively regulate Th17 differentiation and IL-17 expression.MBD2 binds to the CpG islands in the promoter region of interferon regu-latory factor 4(IRF4),suppressor of cytokine signaling 3(S0CS3),hypoxia-inducible factor-1α(HIF-1α)and misshapen like kinase 1(MINK1),which leads to methylation,regulates the differentiation of Th 17 cells,and par-ticipates in the pathogenesis of severe asthma.

Objective: To clarify chemical dynamic change of volatile oil of Root of Changium Smyrnioides Wolff during Processing, to analyse and study the change of constituent proportion to see if new constituents produce or original constituents disappear, to discuss the processing mechanism of root of Changium smyrnioides . Method: The constituents and contain of volatile oils of root of Changium smyrnioides before, during and after processing are comparatively analyzed by using techniques of combined capillary gas chromatography mass spectrometry computer. Result: 34 chemical compounds are identified, among them there were 29 compounds isolated from volatile oil of fresh root of Changium smyrnioides, with a proportion of 97.873% in total oil, its main constituent is CSY and its content reaches 70.946%; 34 compounds were isolated from volatile oil of fresh decorticated root of Changium smyrnioides, with a propoction of 93.452%, main constituent is CSY, its content reaches 75.909%; and 19 compounds from volatile oil of fresh root cortices of Changium smyrnioides, 96.878% , main constituent is CSY, content 70.977%; 11 compounds from volatile oil of processed root of Changium smyrnioides, 88.839%, main constituent is CSY, content 67.234%. Conclusion: Main reasons of non sensibilization of processed root of Changium smyrnioides are considered to be the content decrease and qualitative change of the volatile oils, and the content of snsibilization activity constituent——CSY decreased from 0.0497% to 0.0134%.