Analysis Of Ethanol Extract Of Chinese Propolis By Ultraviolet Spectrum And GC-MS

In order to further study the chemical compositions of propolis in China,and to explore the differences between the different climatic zones and the color of propolis,and to study and obtain the different characteristics of different climatic zones and color samples,gas chromatography-mass spectrometry(GC-MS)and silylation derivatization were used to identify the ethanol extracts from 37 propolis and 1 resin from 22 provinces of China.The multivariate analysis was then performed.In addition,in order to carry out a simple and rapid initial quality detection of propolis,the ethanol extract of 37 propolis samples(EEP)collected from China was scanned by UV,and the obtained EEP UV scanning data were carried through multivariate analysis.The contents of total phenolics,total flavonoids,specific absorbance and scavenging free radical activity of DPPH were determined in EEP,and then a regression model was established combined with UV scaning data.The results are as follows:1.Identification of ethanol extracts from 37 propolis and 1 resin by GC-MS combined with silylation derivatization,the results show that a total of 124 compounds were identified in 37 EEP,including 25 polyphenolic compounds,8terpenoids,40 sugars and their derivatives,and mainly monosaccharides,7 fatty acids and their esters,7 alcohols,7 acids,11 ketones,2 ethers,and 9 steroids,in addition,8other kinds of compounds were identified.The main components are Benzoic acid(0.13% ~ 0.48%),3,4-Dimethoxycinnamic acid(0.13% ~ 1.28%),Ferulic acid(0.28~ 4.02%),Caffeic acid(0.18% ~ 7.14%)and Oleic acid(0.06% ~ 7.56%),in which caffeic acid is detected in most propolis samples,except in FJ-1,HN-3 and HN-4.This study also identified 40 compounds which were not found in the previous studies,such as Myo-inositol,2-amino-3-hydroxy-,benzoic acid,methyl ester,?-friedelinol,1,1-di-C-octyl,D-Glucitol,Castanopsone and so on.Meanwhile,typical poplar type propolis compounds such as caffeic acid,3,4-Dimethoxycinnamic acid,p-Coumaric acid,Ferulic acid were detected,which further proved that Chinese propolis is poplar type propolis.In addition,two Shandong propolis samples were identified to contain the main components of birch bark,therefore,birch tree could be one of the propolis source plants in China,at least in some regions.The results of principal component analysis(PCA)showed that the chemical composition of yellow green and yellowpropolis was similar,and they are different with black propolis significantly,the content of carbohydrate in tropical propolis is higher than that in other climatic zones.Linear discriminant analysis(LDA)discriminant function model can effectively distinguish between different colors of propolis.19 components,such as Dihydrocodeine Bitartrate,Betulin and ?-Gurjunene and so on,variated in the content for the propolis samples with different colors.Categorical variables by climatic zone,were used to establish a discriminant function model that can effectively distinguish tropical propolis,among which the contents of 10 kinds of compounds,such as?-Gurjunene,D-Arabinose,D-Fructose and so on,were obviously different in different climate zones.2.37 ethanol extracts of propolis(EEP)from China were scanned by ultraviolet spectroscopy(UV),and the UV scanning data were then analyzed by PCA and LDA.The contents of total phenolics and total flavonoids,scavenging DPPH free radical activity and specific absorption rate of EEP were determined.The results showed that three principal components were extracted by PCA of UV scanning data,with the cumulative contribution 82.6%,and black propolis were separated from other propolis.Three principal components were extracted by PCA of the integration of UV scanning data,with the cumulative contribution 92.8%,different quality propolis could be distinguished.The classification accuracy rate of LDA was 97.297%,and the success rate of cross validation was 91.891%.Therefore,the model can be used to distinguish the different colors of propolis effectively,and UV combined with multivariate analysis could distinguish different quality propolis.At the same time,a multiple linear regression model was established to determine the content of total phenolics,total flavonoids,specific absorbance and scavenging DPPH free radical activity,and the three properties of propolis were predicted.Based on the analysis of EEP,GC-MS combined with silylation derivatization has a great influence on both the identification of new compnents in propolisand the relationship between the influencing factors and chemical compositions of propolis when multivariate analysis is performed.In addition,UV combined with multivariate analysis can provide a research method for the preliminary identification of propolis quality.