{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:57:28Z","timestamp":1787029048672,"version":"build-2736575974"},"reference-count":39,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2020,7,4]],"date-time":"2020-07-04T00:00:00Z","timestamp":1593820800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004396","name":"Thailand Research Fund","doi-asserted-by":"publisher","award":["MRG6280024"],"award-info":[{"award-number":["MRG6280024"]}],"id":[{"id":"10.13039\/501100004396","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Higher Education Commission, Thailand","award":["MRG6280024"],"award-info":[{"award-number":["MRG6280024"]}]},{"DOI":"10.13039\/501100002873","name":"Chulalongkorn University","doi-asserted-by":"publisher","award":["DNS62_081_23_014_2"],"award-info":[{"award-number":["DNS62_081_23_014_2"]}],"id":[{"id":"10.13039\/501100002873","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Alkyl quinolone has been proven to be a privileged scaffold in the antimicrobial drug discovery pipeline. In this study, a series of new 4-hydroxy-2-quinolinone analogs containing a long alkyl side chain at C-3 and a broad range of substituents on the C-6 and C-7 positions were synthesized. The antibacterial and antifungal activities of these analogs against Staphylococcus aureus, Escherichia coli, and Aspergillus flavus were investigated. The structure-activity relationship study revealed that the length of the alkyl chain, as well as the type of substituent, has a dramatic impact on the antimicrobial activities. Particularly, the brominated analogs 3j with a nonyl side chain exhibited exceptional antifungal activities against A. flavus (half maximal inhibitory concentration (IC50) = 1.05 \u00b5g\/mL), which surpassed that of the amphotericin B used as a positive control. The antibacterial activity against S. aureus, although not as potent, showed a similar trend to the antifungal activity. The data suggest that the 4-hydroxy-2-quinolone is a promising framework for the further development of new antimicrobial agents, especially for antifungal treatment.<\/jats:p>","DOI":"10.3390\/molecules25133059","type":"journal-article","created":{"date-parts":[[2020,7,6]],"date-time":"2020-07-06T11:07:42Z","timestamp":1594033662000},"page":"3059","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Synthesis and Antimicrobial Activity of Novel 4-Hydroxy-2-quinolone Analogs"],"prefix":"10.3390","volume":"25","author":[{"given":"Thitiphong","family":"Khamkhenshorngphanuch","sequence":"first","affiliation":[{"name":"Department of General Education, Faculty of Science and Health Technology, Navamindradhiraj University, Bangkok 10300, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kittipat","family":"Kulkraisri","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alongkorn","family":"Janjamratsaeng","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Napasawan","family":"Plabutong","sequence":"additional","affiliation":[{"name":"Antimicrobial Resistance and Stewardship Research Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0482-4176","authenticated-orcid":false,"given":"Arsa","family":"Thammahong","sequence":"additional","affiliation":[{"name":"Antimicrobial Resistance and Stewardship Research Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kanitta","family":"Manadee","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarisa","family":"Na Pombejra","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7236-0625","authenticated-orcid":false,"given":"Tanatorn","family":"Khotavivattana","sequence":"additional","affiliation":[{"name":"Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,7,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1645","DOI":"10.2147\/IDR.S173867","article-title":"Antibiotic Resistance: A Rundown of a Global Crisis","volume":"11","author":"Aslam","year":"2018","journal-title":"Infect. 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