{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T10:25:25Z","timestamp":1787221525593,"version":"build-2736575974"},"reference-count":39,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T00:00:00Z","timestamp":1787184000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"The Science and Technology Tackling Key Project of Henan Province","award":["252102311280"],"award-info":[{"award-number":["252102311280"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>1-Deoxynojirimycin (DNJ), a well-characterized \u03b1-glucosidase inhibitor, remains an important target for dose-reduction and formulation strategies. In the present study, we evaluated the individual and combined \u03b1-glucosidase inhibitory activities of nine dietary flavonoids with DNJ, quantified synergistic effects using the combination index (CI) method, and elucidated the molecular mechanism through integrated enzyme kinetics, multi-spectroscopic techniques and molecular docking. (+)-Catechin exhibited the strongest inhibitory activity (IC50 = 33.7 \u00b1 2.7 \u03bcM), and its combination with DNJ produced synergistic inhibition across all doses (CI &lt; 0.7). Kinetic analysis confirmed that DNJ acted as a competitive inhibitor, while (+)-catechin functioned as a non-competitive inhibitor. Fluorescence quenching assays revealed that (+)-catechin pre-incubation increased the binding affinity of DNJ to \u03b1-glucosidase by 393%. Circular dichroism spectroscopy showed that (+)-catechin induced a marked \u03b2-sheet-to-\u03b1-helix conformational conversion, and co-incubation of both inhibitors produced more secondary structural changes than either inhibitor alone. Molecular docking further confirmed their distinct binding sites. These findings demonstrate that (+)-catechin synergistically potentiates DNJ activity through allosteric conformational modulation, providing an experimental basis for optimizing DNJ-containing formulations.<\/jats:p>","DOI":"10.3390\/molecules31162907","type":"journal-article","created":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T09:48:31Z","timestamp":1787219311000},"page":"2907","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Screening of Dietary Flavonoids for Synergistic \u03b1-Glucosidase Inhibition with 1-Deoxynojirimycin and Elucidation of the Underlying Molecular Mechanism"],"prefix":"10.3390","volume":"31","author":[{"given":"Lin","family":"Wang","sequence":"first","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yonghong","family":"Zhao","sequence":"additional","affiliation":[{"name":"Nanjing Institute for Food and Drug Control, Nanjing 211198, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhongshan","family":"Xiao","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Puyang Medical College, Puyang 475000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Zeng","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhuming","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Baogang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Food Science and Engineering, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinping","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Xinyang Agriculture and Forestry University, Xinyang 464000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"201418","DOI":"10.1016\/j.humgen.2025.201418","article-title":"Common biomarker genes associated with cardiovascular disease and diabetes mellitus: Implications for cross-disease therapeutic strategies and cancer prognosis","volume":"44","author":"Azmal","year":"2025","journal-title":"Hum. Gene"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"823","DOI":"10.1161\/01.ATV.20.3.823","article-title":"Diabetes mellitus","volume":"20","author":"Kuller","year":"2000","journal-title":"Arterioscler. Thromb. Vasc. Biol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.jff.2018.07.022","article-title":"Exploring inhibitory mechanism of gallocatechin gallate on \u03b1-amylase and \u03b1-glucosidase relevant to postprandial hyperglycemia","volume":"48","author":"Wu","year":"2018","journal-title":"J. Funct. Foods"},{"key":"ref_4","first-page":"815","article-title":"Glycosidase inhibitors: Structure, activity, synthesis, and medical relevance","volume":"Volume 1","author":"Kamerling","year":"2007","journal-title":"Comprehensive Glycoscience"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"105659","DOI":"10.1016\/j.fbio.2024.105659","article-title":"Inhibitory mechanism of \u03b1-glucosidase by liquiritigenin and its combined effect with acarbose: Multi-spectroscopic analyses and molecular docking simulation","volume":"63","author":"Zhou","year":"2025","journal-title":"Food Biosci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1607","DOI":"10.1016\/S0140-6736(09)60222-1","article-title":"Voglibose for prevention of type 2 diabetes mellitus: A randomised, double-blind trial in Japanese individuals with impaired glucose tolerance","volume":"373","author":"Kawamori","year":"2009","journal-title":"Lancet"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1186\/1743-7075-11-14","article-title":"Miglitol increases energy expenditure by upregulating uncoupling protein 1 of brown adipose tissue and reduces obesity in dietary-induced obese mice","volume":"11","author":"Sugimoto","year":"2014","journal-title":"Nutr. Metab."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"141281","DOI":"10.1016\/j.foodchem.2024.141281","article-title":"Enrichment of deoxynojirimycin in mulberry using cation exchange resin: Adsorption\/desorption characteristics and process optimization","volume":"463","author":"Ma","year":"2025","journal-title":"Food Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1645","DOI":"10.1016\/S0957-4166(00)00113-0","article-title":"Sugar-mimic glycosidase inhibitors: Natural occurrence, biological activity and prospects for therapeutic application","volume":"11","author":"Asano","year":"2000","journal-title":"Tetrahedron Asymmetry"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2210","DOI":"10.1271\/bbb.80200","article-title":"Validation of an ion trap tandem mass spectrometric analysis of mulberry 1-deoxynojirimycin in human plasma: Application to pharmacokinetic studies","volume":"72","author":"Nakagawa","year":"2008","journal-title":"Biosci. Biotechnol. Biochem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8928","DOI":"10.1021\/jf071559m","article-title":"Occurrence of orally administered mulberry 1-deoxynojirimycin in rat plasma","volume":"55","author":"Nakagawa","year":"2007","journal-title":"J. Agric. Food Chem."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Marchetti, L., Truzzi, E., Rossi, M.C., Benvenuti, S., Cappellozza, S., Saviane, A., Bogataj, L., Siligardi, C., and Bertelli, D. (2024). Alginate-based carriers loaded with mulberry (Morus alba L.) leaf extract: A promising strategy for prolonging 1-deoxynojirimycin (DNJ) systemic activity for the nutraceutical management of hyperglycemic conditions. Molecules, 29.","DOI":"10.3390\/molecules29040797"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"105296","DOI":"10.1016\/j.tifs.2025.105296","article-title":"Advances in flavonoid glycosylation: Chemical and biological basis, mechanisms, physicochemical properties, and applications in the food industry","volume":"165","author":"Lai","year":"2025","journal-title":"Trends Food Sci. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e15734072312202","DOI":"10.2174\/0115734072312202240729080240","article-title":"Biological estimation of phenolic-flavonoid contents for in vitro antioxidant activity and antidiabetic activities of Selaginella plana in experimental models","volume":"21","author":"Singh","year":"2025","journal-title":"Curr. Bioact. Compd."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"155106","DOI":"10.1016\/j.phymed.2023.155106","article-title":"Combinational application of the natural products 1-deoxynojirimycin and morin ameliorates insulin resistance and lipid accumulation in prediabetic mice","volume":"121","author":"Ren","year":"2023","journal-title":"Phytomedicine"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1211\/jpp.59.8.0013","article-title":"Combined effect of total alkaloids from Feculae Bombycis and natural flavonoids on diabetes","volume":"59","author":"Geng","year":"2007","journal-title":"J. Pharm. Pharmacol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1270","DOI":"10.2174\/092986610792231492","article-title":"Inhibition kinetics of flavonoids on yeast \u03b1-glucosidase merged with docking simulations","volume":"17","author":"Xu","year":"2010","journal-title":"Protein Pept. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2661","DOI":"10.2174\/092986711795933777","article-title":"Flavonoids as promising lead compounds in type 2 diabetes mellitus: Molecules of interest and structure-activity relationship","volume":"18","author":"Nicolle","year":"2011","journal-title":"Curr. Med. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Silva, E.L., Lobo, J.F., Vinther, J.M., Borges, R.M., and Staerk, D. (2016). High-resolution \u03b1-glucosidase inhibition profiling combined with HPLC-HRMS-SPE-NMR for identification of antidiabetic compounds in Eremanthus crotonoides (Asteraceae). Molecules, 21.","DOI":"10.3390\/molecules21060782"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1515","DOI":"10.1016\/j.bmc.2014.01.038","article-title":"Synthesis, nitric oxide release, and \u03b1-glucosidase inhibition of nitric oxide donating apigenin and chrysin derivatives","volume":"22","author":"Wang","year":"2014","journal-title":"Bioorg. Med. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1007\/s00894-017-3438-1","article-title":"Docking-assisted 3D-QSAR studies on xanthones as \u03b1-glucosidase inhibitors","volume":"23","author":"Zheng","year":"2017","journal-title":"J. Mol. Model."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"137365","DOI":"10.1016\/j.ijbiomac.2024.137365","article-title":"Inhibition mechanisms of \u03b1-glucosidase by eight catechins: Kinetic, molecular docking, and surface plasmon resonance analysis","volume":"283","author":"Zhang","year":"2024","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3468","DOI":"10.1080\/10408398.2021.1989660","article-title":"A comprehensive review on the production, pharmacokinetics and health benefits of mulberry leaf iminosugars: Main focus on 1-deoxynojirimycin, d-fagomine, and 2-O-\u03b1-d-galactopyranosyl-DNJ","volume":"63","author":"Parida","year":"2023","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"8774","DOI":"10.1021\/acs.jafc.0c01668","article-title":"Dietary 5,6,7-trihydroxy-flavonoid aglycones and 1-deoxynojirimycin synergistically inhibit the recombinant maltase\u2013glucoamylase subunit of \u03b1-glucosidase and lower postprandial blood glucose","volume":"68","author":"Dong","year":"2020","journal-title":"J. Agric. Food Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1255","DOI":"10.1021\/acsfoodscitech.3c00146","article-title":"Synergistic effect of acarbose\u2013chlorogenic acid on \u03b1-glucosidase inhibition: Kinetics and interaction studies reveal mixed-type inhibition and denaturant effect of chlorogenic acid","volume":"3","author":"Abioye","year":"2023","journal-title":"ACS Food Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"146103","DOI":"10.1016\/j.ijbiomac.2025.146103","article-title":"The synergistic inhibition of isoginkgetin with miglitol and acarbose on \u03b1-glucosidase: Dynamics enzyme changes tracking","volume":"321","author":"Li","year":"2025","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"134575","DOI":"10.1016\/j.molstruc.2022.134575","article-title":"Synthesis, biological evaluation and molecular docking studies of chromone derivatives as potential \u03b1-glucosidase inhibitors","volume":"1274","author":"Fan","year":"2023","journal-title":"J. Mol. Struct."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"108476","DOI":"10.1016\/j.bioorg.2025.108476","article-title":"Interaction mechanisms between \u03b1-glucosidase and procyanidin dimers with different galloyl moiety: Multi-spectral analysis and molecular dynamics simulation","volume":"160","author":"Wang","year":"2025","journal-title":"Bioorg. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"8110","DOI":"10.1021\/jf4019323","article-title":"Comparison of inhibitory activities and mechanisms of five mulberry plant bioactive components against \u03b1-glucosidase","volume":"61","author":"He","year":"2013","journal-title":"J. Agric. Food Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"8784","DOI":"10.1074\/jbc.RA120.013595","article-title":"Structure\u2013function analysis of silkworm sucrose hydrolase uncovers the mechanism of substrate specificity in GH13 subfamily 17 exo-\u03b1-glucosidases","volume":"295","author":"Miyazaki","year":"2020","journal-title":"J. Biol. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1552","DOI":"10.1271\/bbb.66.1552","article-title":"Alpha-glucosidase inhibitory activity of a 70% methanol extract from ezoishige (Pelvetia babingtonii de Toni) and its effect on the elevation of blood glucose level in rats","volume":"66","author":"Ohta","year":"2002","journal-title":"Biosci. Biotechnol. Biochem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"890","DOI":"10.1016\/j.biopha.2017.04.080","article-title":"Combination of flavonoids from Oroxylum indicum seed extracts and acarbose improves the inhibition of postprandial blood glucose: In vivo and in vitro study","volume":"91","author":"Zhang","year":"2017","journal-title":"Biomed. Pharmacother."},{"key":"ref_33","first-page":"102692","article-title":"Exploring the inhibitory mechanism of icaritin on \u03b1-glucosidase and synergistic effect with acarbose by inhibition kinetics, molecular docking, multi-spectroscopic methods and in vivo hypoglycemic model","volume":"26","author":"Peng","year":"2026","journal-title":"J. Agric. Food Res."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"7784","DOI":"10.1021\/acs.jafc.5b03386","article-title":"Dietary flavonoids as xanthine oxidase inhibitors: Structure\u2013affinity and structure\u2013activity relationships","volume":"63","author":"Lin","year":"2015","journal-title":"J. Agric. Food Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"101711","DOI":"10.1016\/j.fbio.2022.101711","article-title":"In vitro xanthine oxidase inhibitory properties of Flos Sophorae Immaturus and potential mechanisms","volume":"47","author":"Li","year":"2022","journal-title":"Food Biosci."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"117444","DOI":"10.1016\/j.lwt.2025.117444","article-title":"New insights into the indirect reduction of starch digestibility by L-theanine: Elucidation of the mechanism of \u03b1-amylase\/\u03b1-glucosidase inhibition based on spectroscopic and computational perspectives","volume":"217","author":"Hao","year":"2025","journal-title":"LWT"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"6726","DOI":"10.1021\/jf070905x","article-title":"Interaction of different polyphenols with bovine serum albumin (BSA) and human salivary \u03b1-amylase (HSA) by fluorescence quenching","volume":"55","author":"Soares","year":"2007","journal-title":"J. Agric. Food Chem."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"3891","DOI":"10.1021\/acs.jcim.1c00203","article-title":"AutoDock Vina 1.2.0: New docking methods, expanded force field, and Python bindings","volume":"61","author":"Eberhardt","year":"2021","journal-title":"J. Chem. Inf. Model."},{"key":"ref_39","unstructured":"DeLano, W.L. (2002). PyMOL: An Open-Source Molecular Graphics Tool, DeLano Scientific."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/16\/2907\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T09:49:15Z","timestamp":1787219355000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/16\/2907"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,20]]},"references-count":39,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["molecules31162907"],"URL":"https:\/\/doi.org\/10.3390\/molecules31162907","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,20]]}}}