AUTHOR=Zhou Hua , Liao Jin , Ou Juanying , Lin Jiayu , Zheng Jie , Li Yifei , Ou Shiyi , Liu Fu 

TITLE=Bioassay-guided isolation of Fenghuang Dancong tea constituents with α-glucosidase inhibition activities

JOURNAL=Frontiers in Nutrition

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.1050614

DOI=10.3389/fnut.2022.1050614

ISSN=2296-861X

ABSTRACT=<p>An α-glucosidase inhibition assay showed the ethanolic extract of Fenghuang Dancong tea had potential α-glucosidase inhibitory activity. The most bioactive fraction, which was obtained <italic>via</italic> bioassay-guided isolation of the extract, was further purified to create five compounds, including three novel compounds (<bold>1</bold>–<bold>3</bold>). These compounds were analyzed and identified in detail using high-resolution-mass spectrometry and extensive one-dimensional and two-dimensional NMR spectroscopy experiments. Among the compounds, compound <bold>1</bold> contained <italic>cis</italic> double bonds and showed the strongest α-glucosidase inhibitory activity with an IC<sub>50</sub> value of 7.51 μM, which is significantly lower than that of compound <bold>2</bold> with <italic>trans</italic> double bonds. Enzyme kinetic experiments showed that <bold>1</bold> was a reversible non-competitive α-glucosidase inhibitor.</p>