| 摘要: | Inhibiting enzymes like the alpha-glucosidase (α-glucosidase) to reduce glucose absorption in the digestive system is a promising therapeutic strategy for managing diabetes mellitus (DM). This research aimed to employ a rapid dereplication system to analyse and identify α-glucosidase inhibitory compounds in plant samples that demonstrated strong enzyme inhibition in an in vitro bioassay. Initially, the study evaluated the potential anti-diabetic properties of seven commonly used herbal plants in Malawi, known for their diabetes treatment applications, by testing their ability to inhibit the α-glucosidase enzyme. Further investigations were conducted using the rapid dereplication system and the enzyme subtraction approach for the plant samples that showed significant potential α-glucosidase inhibition.
Crude extracts were incubated with and without the α-glucosidase enzyme and analyzed using UPLC-ESI-Orbitrap-MS/MS. Metabolomic profiling of the extracts revealed numerous peaks, with potential α-glucosidase inhibitors identified by comparing the profiles of enzyme-treated and untreated extracts. Peaks showing an intensity reduction of more than 10% were considered significant changes resulting from the α-glucosidase protein subtraction.
Among the seven plants tested using the in vitro bioassay approach to determine their ability to inhibit the α-glucosidase enzyme, V. nilotica and M. indica crude extracts exhibited strong α-glucosidase inhibition, with inhibition rates of 100% and 99%, respectively, compared to 92% for quercetin, a known α-glucosidase inhibitor, at a concentration of 75 ?g/ml for both the extracts and quercetin. The IC50 values were determined to be 10 ?g/ml for V. nilotica, 12 ?g/ml for M. indica, and 0.7 ?g/ml for quercetin. The dereplication approach quickly identified six potential α-glucosidase inhibiting compounds in both V. nilotica and M. indica. The inhibitors in V. nilotica included gallic acid, catechin, epigallocatechin-3-gallate, ethyl gallate, catechin 7-O-gallate, and catechin 3,7-di-gallate. In M. indica, the inhibitors identified were shikimic acid, iriflophenone 3-C-β-D-glucopyranoside, mangiferin, ethyl gallate, isoquercetin, and benzoic acid, 4,4'-[oxybis(methyleneoxy)]bis[2-hydroxybenzoic acid].
These results suggest that V. nilotica and M. indica from Malawi are promising natural sources of α-glucosidase inhibitors, with potential applications in nutraceutical development. Furthermore, this study demonstrated the effectiveness of the enzyme subtraction dereplication approach for efficient screening and identification of enzyme-inhibiting compounds from plant-based sources. |
