Identification, potency evaluation, and mechanism clarification of α-glucosidase inhibitors from tender leaves of Lithocarpus polystachyus Rehd

Hai-Lian Fang; Mei-Ling Liu; Su-Ya Li; Wan-Qing Song; Hui Ouyang; Zhu-Ping Xiao; Hai-Liang Zhu

doi:10.1016/j.foodchem.2021.131128

Identification, potency evaluation, and mechanism clarification of α-glucosidase inhibitors from tender leaves of Lithocarpus polystachyus Rehd

Food Chem. 2022 Mar 1:371:131128. doi: 10.1016/j.foodchem.2021.131128. Epub 2021 Sep 14.

Authors

Hai-Lian Fang¹, Mei-Ling Liu¹, Su-Ya Li¹, Wan-Qing Song¹, Hui Ouyang¹, Zhu-Ping Xiao², Hai-Liang Zhu³

Affiliations

¹ Hunan Provincial Key Laboratory of Research, Resource Mining and High-valued Utilization on Edible & Medicinal Plant, Hunan Engineering Laboratory for Analyse and Drugs Development of Ethnomedicine in Wuling Mountains, National Demonstration Center for Experimental Chemistry Education, Jishou University, Jishou 416000, PR China.
² Hunan Provincial Key Laboratory of Research, Resource Mining and High-valued Utilization on Edible & Medicinal Plant, Hunan Engineering Laboratory for Analyse and Drugs Development of Ethnomedicine in Wuling Mountains, National Demonstration Center for Experimental Chemistry Education, Jishou University, Jishou 416000, PR China; State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China. Electronic address: xiaozhuping2005@163.com.
³ Hunan Provincial Key Laboratory of Research, Resource Mining and High-valued Utilization on Edible & Medicinal Plant, Hunan Engineering Laboratory for Analyse and Drugs Development of Ethnomedicine in Wuling Mountains, National Demonstration Center for Experimental Chemistry Education, Jishou University, Jishou 416000, PR China; State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China. Electronic address: zhuhl@nju.edu.cn.

PMID: 34563970
DOI: 10.1016/j.foodchem.2021.131128

Abstract

Lithocarpus polystachyus Rehd. known as Sweet Tea in China has attracted lots of interest for its good hypoglycemic effect and the potential as a hypoglycemic agent. Based on affinity separation-UPLC-Q-TOF-MS/MS, 54 potential α-glucosidase inhibitiors were identified and 44 were structurally determined. Out of them, 41 were identified for the first time from this plant including flavonoids, fatty acids, triterpenes, alkaloids, and coumarins. Enzyme assays revealed that flavonoids exhibited higher inhibitory activity against α-glucosidase than others with astilbin (IC₅₀ = 6.14 μg·mL^-1), morin (IC₅₀ = 8.46 μg·mL^-1), and naringenin (IC₅₀ = 10.03 μg·mL^-1) showing 2- to 4-fold higher potency than the positive control acarbose. They were proved as reversible inhibitors with mixed inhibition mechanism. K_i (K_i^') values and molecular dockings strongly supported the potency order of astilbin, morin and naringenin that showed in the enzyme assays.

Keywords: Flavonoids; Hypoglycemic potency; Lithocarpus polystachyus Rehd.; α-Glucosidase inhibitior.

MeSH terms

Fagaceae*
Glycoside Hydrolase Inhibitors*
Hypoglycemic Agents
Plant Extracts
Plant Leaves
Tandem Mass Spectrometry
alpha-Glucosidases

Substances

Glycoside Hydrolase Inhibitors
Hypoglycemic Agents
Plant Extracts
alpha-Glucosidases