Research On Optimization For Extraction And Isolation Of Tea Flower Flavones And Variances Of Tea Flower Flavones Among Various Cultivars

The study has explored the extraction and separation of flavonoids from tea flowers and analyzed its distributive difference among the tea flowers from different cultivars.The optimal extraction condition through response surface method was determinated,and the best macroporous resin by static adsorption experiment,concluding the optimal separation condition by dynamic adsorption experiment was selected.The identification and quantification of tea floral flavone glycosides from five cultivars by utilizing an established UPLC-MS method was conducted.Main conclusions are as follows:1.The results of response surface method showed that the optimal extraction condition for reflux extraction under Box-Behnken design were as follows:duration of extraction(A)was 1.84 h,ratio of liquid to solid(C)was 54 mL/g,concentration of ethanol(B)was 78%,heating temperature(D)was 75?.The fitting regression equation of the total yield of flavonoids(Y)was:Y=7.06+0.15 A+0.26B+0.25C+0.24D+0.35AB+0.17AD+0.46BC+0.20BD-0.36A2-0.56B2-0.52C2-0.58D2(R2=0.9693),indicating the equation was well fitted.The testing experiment points to this model wass valid with the yield of 7.09 mg/g.2.AB-8 was the best macroporous resin for purification of tea floral flavonoids among AB-8,D-101,DM-301 and DA-201.The adsorptive capacity,desorption rate,and recovering rate were 129.96 mg/g,96.45%,and 69.20%for AB-8 on tea floral flavonoids,respectively.The optimal separation condition of AB-8,while its columned volume was 15 mm*120 mm,were as follows:The flavonoids concentration of the ethanol extract was 1.80 mg/mL,the duration of adsorption was 1h,the concentration of elute was 75%,and the flow rate of elute was 1.5 mL/min.3.Up to 12 of different flavone glycosides from five different cultivars of tea flowers by an established UPLC-MS method were identified and quantifird.The content of Kae-glc-rha-gal and Kae-glc-rha-glc in flowers of huangyezao was significantly higher than those of other cultivars,the content of Myr-glc in the flower of fujianshuixian was 4 times higher than that of the rest.However,its Myr-gal's content is only afifth of others'.The total amount of floral flavone glycosides in zhenghe white tea was the least of all,the content of Kaempferol glycosides is the highest and the content of Myricetin glycosides was the lowest in all the tested cultivars,and the majority of them were glycosylated with tri-glycosides.