Study On Extraction And Separation Of Flavonoids From Huoshan Yellow Tea

Tea is one of the most popular drinks in the world nowdays.In recent years,the consumption of tea has increased dramatically.With more than 2 billion people in nearly 125 countries drinking tea,mainly because tea provides significant health benefits.According to the different processing methods of tea,tea can be roughly divided into six categories,which are green tea(unfermented),yellow tea and white tea(micro-fermented,10-20%),oolong tea(semi-fermented,30-60%),black tea(full-fermented,80-100%)and black tea(post-fermented,100%).The yellow tea is known and drink with a minimum of all kind of teas.But yellow tea is becoming popular gradually because of its unique flavor,refreshing,smooth taste,excellent quality and human health-protecting.Flavonoid glycosides in tea are rich and various,and have good health effects on anti-cancer,anti-oxidation and anti-bacteria.However,the chemical composition in tea is complex,and there are many problems in the process of separating and purifying these flavonoid glycosides,such as time-consuming,poor accuracy and large sample consump?tion.It is necessary to find a method to quickly identify the chemical components in tea and then purposefully isolate and purify the target compounds.High performance liquid phase-high resolution mass spectrometry(hplc-ms)is used to identify the chemical components of tea leaves by combining with the existing database data of tea metabolites which avoids the disadvantages of traditional natural product's separation method.In the experiment,the sample weight are smaller,the identification time is shorter,and the analysis is more comprehensive,which provides the direction and basis for the efficient separation and purification of target compounds.In this study,the polyphenols and flavonoid glycosides from different extracts of Huoshan yellow tea were analyzed by HPLC-HRMS.Combined with the literature data in the tea metabolites database,these compounds were analyzed and identified.In addition,eight flavonoids were isolated and purified by traditional natural product separation method.The chemical structures of these 8 compounds were determined by hydrogen spectrum analysis and the data reported in the existing literature,which are 3-O-[?-L-arabinopyranosyl(1-3)][2-O"-(E)-p-coumaroyl][?-L-rhamnopyranosyl(1-6)]-?-D-glucoside,Isoquercitrin,ChafurosideA,2"-O-rhamnosyl vitexin,Astragal in,kaempferol 3-O-?-D-galactopyranoside,KaemPferol-3-O-galactosyl-6-O-rharnosideKaempferol-3-O-[?-D-Glucopyranosyl-(1-3)-?-L-rha-mno pyranosyl-(1-6)-?-D-glucopyranoside].By comparing the four flavonoid glycosides in yellow tea with other different tea types,the content of these four flavonoid glycosides in yellow tea is the second highest.It is speculated that flavonols and different sugars may combine to form flavonoid glycosides due to the intense damp-heat effect in the key process of flavonoid tea production,which increase the content of flavonoid glycosides.This experiment lies in the application of high performance liquid chromatography-high resolution mass spectrometry technology to different extraction parts of Huoshan yellow tea combined with the existing literature data of tea metabolite database.The components of flavonoid glycosides in the extracted parts were analyzed,and the chemical structures of 8 flavonoid glycosides were determined by using hydrogen spectrum analysis and literature data of tea metabolite database,which provided a new method to separate different components in tea accurately and efficiently.