Larger-leaf yellow tea(LYT)is a characteristic type of Chinese tea produced in Huoshan County,Anhui Province,which is made by mature leaves with stems.According to recent report,LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea.However,the bioactive compounds of LYT are still undiscovered so far.For this purpose,5 fractions of LYT were prepared by sequential extraction.The in vitro bioassay results indicated that the ethyl acetate fraction of LYT had the strongest inhibitory effects on α-glucosidase and α-amylase.Fluorescence-quenching analysis and protein-binding test revealed that the compounds of ethyl acetate fraction could inhibit α-glucosidase and α-amylase activities through binding to enzymes or other mechanisms.All chromatographic peaks of high-performance liquid chromatography(HPLC)of ethyl acetate fraction were separated and collected.The purified compounds were identified by liquid chromatography-mass spectrometry(LC-MS),and subsequently screened by calculating their inhibition ratio on α-glucosidase at the real concentration in LYT infusion.The results showed that(-)-epigallocatechin gallate,(-)-gallocatechin gallate,caffeine,N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors for α-glucosidase.

You Wu;Zisheng Han;Mingchun Wen;Chi-Tang Ho;Zongde Jiang;Yijun Wang;Na Xu;Zhongwen Xie;Jinsong Zhang;Liang Zhang;Xiaochun Wan

State Key Laboratory of Tea Plant Biology and Utilization,Anhui Agricultural University,Hefei 230036,China;International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education,Anhui Agricultural University,Hefei 230036,China;Department of Food Science,Rutgers University,New Brunswick,NJ 08901,USA

食品科学与人类健康（英文）

[1]You Wu;Zisheng Han;Mingchun Wen;Chi-Tang Ho;Zongde Jiang;Yijun Wang;Na Xu;Zhongwen Xie;Jinsong Zhang;Liang Zhang;Xiaochun Wan-.Screening of α-glucosidase inhibitors in large-leaf yellow tea by offline bioassay coupled with liquid chromatography tandem mass spectrometry)[J].食品科学与人类健康（英文）,2022(03):627-634

LYT,Huoshan,undiscovered,flavan

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