title: Inhibition of three selected beverage extracts on alpha-glucosidase and rapid identification of their active compounds using HPLC-DAD-MS/MS and biochemical detection.
abstract: Inhibition of alpha-glucosidase is a therapeutic approach for diabetes. In this study, a method based on online liquid chromatography-diode array detection-tandem mass spectrometry and biochemical detection (LC-DAD-MS/MS-BCD) was developed to screen and identify alpha-glucosidase inhibitors from selected beverage extracts, including pu-erh tea ( Camellia sinensis var. assamica), eagle tea ( Litsea coreana Levl.), and radix glycyrrhizae ( Glycyrrhiza uralensis Fisch.). As a result, two components, (-)-epigallocatechingallate (EGCG) and (-)-epicatechingallate (ECG), as potent alpha-glucosidase inhibitors, were found in pu-erh tea. The IC(50) values of EGCG and ECG on alpha-glucosidase (EC 3.2.1.20, from Saccharomyces cerevisiae ) were 175.1 and 246.9 microM, respectively, and both were lower than that of acarbose (IC(50) = 3553.0 microM), a commercial alpha-glucosidase inhibitor. Kinetic studies revealed that both EGCG and ECG inhibited alpha-glucosidase activity in a noncompetitive manner. The study suggests that the developed LC-DAD-MS/MS-BCD system is a powerful tool for rapid screening and identification of alpha-glucosidase inhibitors in complex samples and that EGCG and ECG may be good candidates as alpha-glucosidase inhibitors.
authors.affiliation: Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China.
authors.forename: De-Qiang
authors.initials: DQ
authors.lastname: Li
authors.forename: Zheng-Ming
authors.initials: ZM
authors.lastname: Qian
authors.forename: Shao-Ping
authors.initials: SP
authors.lastname: Li
mesh_terms: D001628:Beverages / Q000032:analysis*; D001671:Biochemistry / Q000379:methods*; D028241:Camellia sinensis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000737:chemistry*; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D065089:Glycoside Hydrolase Inhibitors; D006035:Glycyrrhiza / Q000737:chemistry; D007700:Kinetics; D032862:Litsea / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D053719:Tandem Mass Spectrometry / Q000379:methods*; D000520:alpha-Glucosidases / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D065089:Glycoside Hydrolase Inhibitors; D010936:Plant Extracts; D000520:alpha-Glucosidases