{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:31:28Z","timestamp":1760236288513,"version":"build-2065373602"},"reference-count":75,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2021,11,10]],"date-time":"2021-11-10T00:00:00Z","timestamp":1636502400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/04423\/2020, UIDP\/04423\/2020","PTDC\/SAU-PUB\/28736\/2017 (reference POCI-01\u20130145-FEDER-028736)"],"award-info":[{"award-number":["UIDB\/04423\/2020, UIDP\/04423\/2020","PTDC\/SAU-PUB\/28736\/2017 (reference POCI-01\u20130145-FEDER-028736)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100006742","name":"Cooperativa de Ensino Superior Polit\u00e9cnico e Universit\u00e1rio","doi-asserted-by":"publisher","award":["CHIRALBIO ACTIVE-PI-3RL-IINFACTS-2019, CHIRALSINTESE-APSFCT-IINFACTS_2021"],"award-info":[{"award-number":["CHIRALBIO ACTIVE-PI-3RL-IINFACTS-2019, CHIRALSINTESE-APSFCT-IINFACTS_2021"]}],"id":[{"id":"10.13039\/501100006742","id-type":"DOI","asserted-by":"publisher"}]},{"name":"NORTE2020","award":["R&D&I ATLANTIDA (NORTE-01-0145-FEDER-000040)"],"award-info":[{"award-number":["R&D&I ATLANTIDA (NORTE-01-0145-FEDER-000040)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>Antimicrobial peptides are one of the lines of defense produced by several hosts in response to bacterial infections. Inspired by them and recent discoveries of xanthones as bacterial efflux pump inhibitors, chiral amides with a xanthone scaffold were planned to be potential antimicrobial adjuvants. The chiral derivatives of xanthones were obtained by peptide coupling reactions between suitable xanthones with enantiomerically pure building blocks, yielding derivatives with high enantiomeric purity. Among 18 compounds investigated for their antimicrobial activity against reference strains of bacteria and fungi, antibacterial activity for the tested strains was not found. Selected compounds were also evaluated for their potential to inhibit bacterial efflux pumps. Compound (R,R)-8 inhibited efflux pumps in the Gram-positive model tested and three compounds, (S,S)-8, (R)-17 and (R,S)-18, displayed the same activity in the Gram-negative strain used. Studies were performed on the inhibition of biofilm formation and quorum-sensing, to which the enantiomeric pair 8 displayed activity for the latter. To gain a better understanding of how the active compounds bind to the efflux pumps, docking studies were performed. Hit compounds were proposed for each activity, and it was shown that enantioselectivity was noticeable and must be considered, as enantiomers displayed differences in activity.<\/jats:p>","DOI":"10.3390\/ph14111141","type":"journal-article","created":{"date-parts":[[2021,11,11]],"date-time":"2021-11-11T23:04:46Z","timestamp":1636671886000},"page":"1141","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Enantioselectivity of Chiral Derivatives of Xanthones in Virulence Effects of Resistant Bacteria"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4201-2774","authenticated-orcid":false,"given":"Fernando","family":"Dur\u00e3es","sequence":"first","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9314-8669","authenticated-orcid":false,"given":"Sara","family":"Cravo","sequence":"additional","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0235-4991","authenticated-orcid":false,"given":"Joana","family":"Freitas-Silva","sequence":"additional","affiliation":[{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"},{"name":"ICBAS\u2014Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8638-5815","authenticated-orcid":false,"given":"Nikoletta","family":"Szemer\u00e9di","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Albert Szent-Gy\u00f6rgyi Health Center and Albert Szent-Gy\u00f6rgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6115-8811","authenticated-orcid":false,"given":"Paulo","family":"Martins-da-Costa","sequence":"additional","affiliation":[{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"},{"name":"ICBAS\u2014Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2948-5809","authenticated-orcid":false,"given":"Eug\u00e9nia","family":"Pinto","sequence":"additional","affiliation":[{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"},{"name":"Laboratory of Microbiology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3320-730X","authenticated-orcid":false,"given":"Maria Elizabeth","family":"Tiritan","sequence":"additional","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"},{"name":"CESPU, Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), Rua Central de Gandra, 1317, 4585-116 Gandra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8085-0950","authenticated-orcid":false,"given":"Gabriella","family":"Spengler","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Albert Szent-Gy\u00f6rgyi Health Center and Albert Szent-Gy\u00f6rgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0940-9163","authenticated-orcid":false,"given":"Carla","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5397-4672","authenticated-orcid":false,"given":"Em\u00edlia","family":"Sousa","sequence":"additional","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4676-1409","authenticated-orcid":false,"given":"Madalena","family":"Pinto","sequence":"additional","affiliation":[{"name":"Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"},{"name":"CIIMAR\u2014Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edif\u00edcio do Terminal de Cruzeiros do Porto de Leix\u00f5es, Avenida General Norton de Matos, S\/N, 4450-208 Matosinhos, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"194","DOI":"10.3389\/fcimb.2016.00194","article-title":"Antimicrobial peptides: An emerging category of therapeutic agents","volume":"6","author":"Mahlapuu","year":"2016","journal-title":"Front. 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