{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T05:17:15Z","timestamp":1788153435532,"version":"build-2803163510"},"reference-count":39,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Olive leaf extract (OLE) contains polyphenolic compounds with reported antioxidant and antimicrobial activities. In this study, OLE obtained by Naviglio extraction was incorporated into zirconia-based sol\u2013gel hybrids at theoretical contents of 8, 25, 33, and 50 wt%. Colorimetric analysis showed that OLE acted as a natural coloring agent, producing composition-dependent changes from yellow to orange\u2013brown tones. FT-IR spectra retained the characteristic bands of the zirconia-based matrix together with OLE-related contributions, while shifts in the O\u2013H and Zr\u2013O regions indicated changes in the local chemical environment after incorporation. Thermal analysis showed a progressive increase in the onset temperature of the main degradation stage, from 296.2 \u00b0C for bare ZrO2 to 320.4 \u00b0C for ZrO2\/OLE50%, suggesting a stabilizing effect of OLE within the hybrid matrix. Release experiments in 95% (v\/v) ethanol showed a clear dependence on OLE content. ZrO2\/OLE8% released almost completely within 5\u20136 h, whereas ZrO2\/OLE25% showed an initial burst followed by slower release, reaching 75\u201380% after 24 h. ZrO2\/OLE33% and ZrO2\/OLE50% showed slower release without a clear burst phase and released less than 30%. Agar-diffusion tests showed no enhancement of antibacterial activity against Escherichia coli or Enterococcus faecalis. These preliminary findings provide a basis for further investigation into the valorization of olive leaf extract as a natural component for the development of colored functional hybrid materials.<\/jats:p>","DOI":"10.3390\/molecules31173020","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T04:24:03Z","timestamp":1788150243000},"page":"3020","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Naturally Colored ZrO2-Based Hybrids Loaded with Olive Leaf Extract: Physicochemical, Thermal and Release Properties"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-9729-0116","authenticated-orcid":false,"given":"Marika","family":"Fiorentino","sequence":"first","affiliation":[{"name":"Department of Engineering, University of Campania \u201cLuigi Vanvitelli\u201d, Via Roma 29, 81031 Aversa, CE, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Maria Vittoria","family":"Mollo","sequence":"additional","affiliation":[{"name":"Department of Engineering, University of Campania \u201cLuigi Vanvitelli\u201d, Via Roma 29, 81031 Aversa, CE, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7768-8745","authenticated-orcid":false,"given":"Antonio","family":"D\u2019Angelo","sequence":"additional","affiliation":[{"name":"Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5191-7669","authenticated-orcid":false,"given":"Daniele","family":"Naviglio","sequence":"additional","affiliation":[{"name":"Department of Chemical Sciences, University of Naples \u201cFederico II\u201d, Via Cinthia, 26, 80126 Napoli, NA, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9252-9435","authenticated-orcid":false,"given":"Ignazio","family":"Blanco","sequence":"additional","affiliation":[{"name":"Department of Civil-Industrial Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, CT, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"software","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4448-6984","authenticated-orcid":false,"given":"Michelina","family":"Catauro","sequence":"additional","affiliation":[{"name":"Department of Engineering, University of Campania \u201cLuigi Vanvitelli\u201d, Via Roma 29, 81031 Aversa, CE, Italy"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Alle, M., Priyadarshi, R., and Purohit, S.D. 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