{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T11:21:30Z","timestamp":1776856890307,"version":"3.51.2"},"reference-count":48,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004704","name":"National Research Council of Thailand (NRCT)","doi-asserted-by":"publisher","award":["N35A650136"],"award-info":[{"award-number":["N35A650136"]}],"id":[{"id":"10.13039\/501100004704","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Fundamental Fund 2025, Chiang Mai University","award":["N35A650136"],"award-info":[{"award-number":["N35A650136"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The emergence of SARS-CoV-2 in 2019 posed significant global public health challenges. One of the most promising targets for novel antiviral drug development is the SARS-CoV-2 main protease (3CLpro). In this study, fragment molecular orbital (FMO) calculations were conducted to provide guidance for the structural modification of natural flavonoids, identifying the pyrogallol moiety as a key candidate. Natural flavonoids were chemically modified to generate 33 semi-synthetic derivatives through the introduction of various functional groups. Our findings revealed that the incorporation of a galloyl moiety significantly enhances anti-proteolytic activity against SARS-CoV-2 3CLpro, achieving up to a 23-fold increase compared to the activity of the parent compounds. Notably, 7-O-galloyl-DMC (40) exhibited the highest anti-proteolytic activity in an enzymatic assay. Additionally, molecular dynamics simulations provided atomic-level insights into the interactions between the galloyl moiety and 3CLpro. All galloylated flavonoid derivatives positioned their galloyl groups within the S1\u2032 sub-pocket, facilitating hydrogen bonding and \u03c0-interactions, particularly with Thr26 and Leu27. These findings underscore the potential of the galloyl moiety as a crucial structural element for enhancing the binding affinity of flavonoids with inhibitory activity against SARS-CoV-2 3CLpro.<\/jats:p>","DOI":"10.3390\/ijms26199742","type":"journal-article","created":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T10:48:07Z","timestamp":1759834087000},"page":"9742","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Discovery of Galloyl\u2013Flavonoid Conjugates as SARS-CoV-2 3CLpro Inhibitors: Understanding Binding Interactions Through Computational Approaches"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2321-3722","authenticated-orcid":false,"given":"Nopawit","family":"Khamto","sequence":"first","affiliation":[{"name":"Department of Biochemistry, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand"},{"name":"Center of Excellence in Medical Biotechnology (CEMB), Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand"},{"name":"Cellular and Molecular Immunology Research Unit, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-6880-0397","authenticated-orcid":false,"given":"Panida","family":"Boontawee","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand"},{"name":"Multidisciplinary and Interdisciplinary School, Chiang Mai University, Chiang Mai 50200, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8565-1843","authenticated-orcid":false,"given":"Vachira","family":"Choommongkol","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai 50290, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1391-7163","authenticated-orcid":false,"given":"Kritsada","family":"Pruksaphon","sequence":"additional","affiliation":[{"name":"Center of Excellence Research for Melioidosis and Microorganisms (CERMM), Walailak University, Nakhon Si Thammarat 80160, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6272-2944","authenticated-orcid":false,"given":"Suwicha","family":"Patnin","sequence":"additional","affiliation":[{"name":"Laboratory of Organic Synthesis, Chulabhorn Research Institute, Bangkok 10210, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2025-6823","authenticated-orcid":false,"given":"Nuttee","family":"Suree","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand"},{"name":"Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6376-7116","authenticated-orcid":false,"given":"Panchika","family":"Prangkio","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand"},{"name":"Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9167-1402","authenticated-orcid":false,"given":"Puttinan","family":"Meepowpan","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand"},{"name":"Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand"},{"name":"Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1016\/S1473-3099(20)30120-1","article-title":"An interactive web-based dashboard to track COVID-19 in real time","volume":"20","author":"Dong","year":"2020","journal-title":"Lancet Infect. 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