{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T11:55:32Z","timestamp":1789646132202,"version":"4.0.0"},"reference-count":49,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,7]],"date-time":"2021-01-07T00:00:00Z","timestamp":1609977600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>The copper (II) complex of ursolic acid (Cu(II) UA) was synthesized and discussed in terms of its infrared, UV\u2013visible spectra, quantum-chemical calculations at B3LYP\/6-31G(d) level and antioxidant capacity. The copper (II) complex was stable in methanolic solution with the molar ratio metal:ligand 1:1. The data obtained by FT-IR confirmed the metal ion coordination through the carboxylate anion. The antioxidant properties of ursolic acid and its complex with Cu were discussed on the basis of energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and values of chemical reactivity parameters. The antiradical properties of ursolic acid and the Cu (II) complex were examined against DPPH\u2022 and HO\u2022 radicals, and the ferric reducing antioxidant power (FRAP) was examined. The Cu(II) complex showed higher antioxidant activity than ursolic acid, i.e., in DPPH\u2022 assay, the EC50 for UA was 47.0 mM, whereas, for Cu(II), UA EC50 = 19.5 mM; the FRAP value for UA was 20.8 \u00b5MFe2+, and 35.4 \u00b5MFe2+ for Cu(II) UA (compound concentration 3 mM). Although there was no distinct difference in the antioxidant activity against HO\u2022 between these two chemicals, they were both better HO\u2022 scavengers than DPPH\u2022 and showed different kinetics in the reaction with DPPH\u2022.<\/jats:p>","DOI":"10.3390\/ma14020264","type":"journal-article","created":{"date-parts":[[2021,1,10]],"date-time":"2021-01-10T21:21:45Z","timestamp":1610313705000},"page":"264","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Enhanced Antioxidant Activity of Ursolic Acid by Complexation with Copper (II): Experimental and Theoretical Study"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4981-0779","authenticated-orcid":false,"given":"Mariola","family":"Samsonowicz","sequence":"first","affiliation":[{"name":"Department of Chemistry, Biology and Biotechnology, Institute of Civil Engineering and Energetics, Faculty of Civil Engineering and Environmental Science, Bialystok University of Technology, Wiejska 45E Street, 15-351 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0839-9891","authenticated-orcid":false,"given":"Monika","family":"Kalinowska","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Biology and Biotechnology, Institute of Civil Engineering and Energetics, Faculty of Civil Engineering and Environmental Science, Bialystok University of Technology, Wiejska 45E Street, 15-351 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3441-4458","authenticated-orcid":false,"given":"Kamila","family":"Gryko","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Biology and Biotechnology, Institute of Civil Engineering and Energetics, Faculty of Civil Engineering and Environmental Science, Bialystok University of Technology, Wiejska 45E Street, 15-351 Bialystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1002\/jsfa.4330","article-title":"Ursolic acid and its esters: Occurrence in cranberries and other Vaccinium fruit and effects on matrix metalloproteinase activity in DU145 prostate tumor cells","volume":"91","author":"Kondo","year":"2011","journal-title":"J. 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