Study On Material Basis Of Antioxidant Activity Of Ethyl Acetate Extract Of Dendrobium Nobile

Objective:To systematically study the chemical constituents of ethyl acetate extract of Dendrobium nobile,and screen out antioxidant monomer compounds from them.Methods:?The ethyl acetate part of 95%ethanol extract of Dendrobium nobile was separated and purified by silica gel chromatography,gel chromatography,and recrystallization.The structure of the compounds were identified based on their physicochemical properties and spectral data;?An UPLC C₁₈?100mm×2.1mm,1.6?m?column was applied with gradient elution of acetonitrile-0.1%formic acid solution,at a flow rate of 0.4 mL/min and 30?of column temperature.MS analysis was based on ESI ion source,independent data acquisition?IDA?.The positive and negative ions were respectively collected.Through retention times,measured accurate relative molecular mass,one-level and two-level mass fragments of every chromatographic peak were compared by Formula Calculator function and so on from MassHunter software,natural product databases.?The oxidation damage of MIO-M1 cells in human retinal cells was induced by L-glutamate,and the antioxidant activity of the compounds isolated from the ethyl acetate extract of Dendrobium nobile in vitro was screened and the cell survival rate was detected by the MTT method.Results:?Sixteen compounds were isolated from Dendrobium nobile and elucidated as coumarin?XJ-1?,E-ferulic acid hexacosyl ester?XJ-2?,dengibsinin?XJ-3?,trans-tetradecyl 3-?4-hydroxyphenyl?propenoate?XJ-4?,nobilone?XJ-5?,densiflorol B?XJ-6?,cypripedin?XJ-7?,naringenin?XJ-8?,?E?-4-?2-methoxyvinyl?benzene-1,2-diol?XJ-9?,moscatin?XJ-10?,moellendorffiline?XJ-11?,isopimpinellin?XJ-12?,denchrysan A?XJ-13?,2,2?-oxybis?1,4-di-tert-butyl-benzene??XJ-14?,dengibsin?XJ-15?,2,4,8-trimethoxy phenanthrene-3,7-diol?XJ-16?;?There were 45 natural compounds identified from ethyl acetate extract of Dendrobium nobile,the main chemical constituents included alkaloids,bibenzils,phenanthrenes,sesquiterpenes et al;?Compounds XJ-1?XJ-4 and XJ-7 had a little antioxidant activity in the certain concentration,compounds XJ-3,XJ-6,XJ-7,XJ-10,XJ-13,XJ-15 and XJ-16 inhibited cell viability at different concentrations.Conclusion:?This research had further enriched the chemical constituents of Dendrobium nobile;?The method was accurate,reliable,suitable for identification of chemical constituents in Dendrobium nobile,it provided a reference for material basis,development and utilization of the resource of Dendrobium nobile.?Preliminarily study on the antioxidant activity of Dendrobium nobile has been carried out herein,it provided a reference for the study of pharmacological activity of Dendrobium nobile.