Inhibition of Three Selected Beverage Extracts on α-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.

Antidiabetic effect of polyphenols from brown algaEcklonia kuromein genetically diabetic KK-Aymice

“…New DPP-4 inhibitors and a GLP-1 mimetic primarily target postprandial hyperglycemia (Ceriello, 2003;Aryangat & Gerich, 2010). Numerous studies indicate that polyphenols, such as tea polyphenols, have inhibitory activities like those of carbohydrate hydrolyzing enzymes Li et al, 2010). In the present study, KPP showed inhibitory activity on α-glucosidase, especially the marked inhibition of α-amylase (Table 1).…”

Development of a bioassay-coupled HPLC-SPE-ttNMR platform for identification of α-glucosidase inhibitors in apple peel (Malus × domestica Borkh.)

“…Direct on-line coupling of enzymatic assays with HPLC puts restraints on conditions used for HPLC separation, because enzyme activity are only compatible with low concentrations of organic modifier. This barrier can to some extent be overcome by applying a counter-gradient of make-up flow that keeps the concentration of the organic modifier at an acceptable level (Shi et al, 2009) or by keeping the concentration of the organic modifier under the critical level (Li, Qian, & Li, 2010). However, the counter-gradient results in peak broadening and lower resolution, and low concentrations of organic modifier will hinder separation of many organic compounds.…”

Characterization and identification of iridoid glucosides, flavonoids and anthraquinones in Hedyotis diffusa by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry

“…HPLC-MS has high sensitivity and fast screening capabilities in detecting target compounds in the complex constituents of CHMs. In addition, it is possible to unravel the structures of these compounds using tandem mass spectrometry (MS n ) or time-of-flight mass spectrometry (TOF/MS) [10][11][12][13][14][15].…”