{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T09:30:55Z","timestamp":1768815055031,"version":"3.49.0"},"reference-count":39,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,10,24]],"date-time":"2025-10-24T00:00:00Z","timestamp":1761264000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o Para a Ci\u00eancia e Tecnologia","award":["UIDB\/00215\/2020"],"award-info":[{"award-number":["UIDB\/00215\/2020"]}]},{"name":"Funda\u00e7\u00e3o Para a Ci\u00eancia e Tecnologia","award":["UIDP\/00215\/2020"],"award-info":[{"award-number":["UIDP\/00215\/2020"]}]},{"name":"Funda\u00e7\u00e3o Para a Ci\u00eancia e Tecnologia","award":["LA\/P\/0064\/2020"],"award-info":[{"award-number":["LA\/P\/0064\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceutics"],"abstract":"<jats:p>Background\/Objectives: Carvacrol and thymol are monoterpenes present in phenolic-rich essential oils extracted from aromatic plants that exhibit antimicrobial activity. This study evaluates the antiprotozoal effect of carvacrol, thymol and their precursor, p-Cymene, against Giardia lamblia and investigates their mechanism of action and cytotoxicity profile. Methods:\u00a0G. lamblia susceptibility, cell viability, swelling and adhesion abilities following application of carvacrol, thymol and p-Cymene were assessed. Ultrastructural changes were evaluated using electron microscopy. Cytotoxicity was determined in mammalian cell lines (murine macrophages RAW 264.7 and bovine aortic endothelial cells) exposed to the same IC50 concentrations effective against G. lamblia. Results: Carvacrol and thymol led to significant inhibition of G. lamblia trophozoite proliferation (IC50 \u2245 50 \u00b5g\/mL). After 7 h of incubation, total cell number decreased by 30% (p &lt; 0.01) with carvacrol and by 50% (p &lt; 0.001) with thymol, accompanied by reduced motility and adhesion (&lt;20% attached cells). At IC50 concentrations, G. lamblia trophozoites exposed to carvacrol and thymol underwent considerable ultrastructural alterations (e.g., aberrant-shaped cells, mitochondrial swelling and autophagosomal structures). Reduced trophozoite motility and adhesion capacity were also observed. In mammalian cells, thymol showed no significant cytotoxicity, whereas carvacrol significantly reduced viability in both cell lines. In contrast, p-Cymene showed no antigiardial activity. Conclusions: Our data suggests that carvacrol and thymol disrupt G. lamblia trophozoite integrity, possibly through alterations in membrane permeability and osmoregulatory processes. In conclusion, these compounds reveal in vitro antigiardial activity, supporting their potential as antigiardial drugs.<\/jats:p>","DOI":"10.3390\/pharmaceutics17111380","type":"journal-article","created":{"date-parts":[[2025,10,27]],"date-time":"2025-10-27T00:51:42Z","timestamp":1761526302000},"page":"1380","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Volatile Compounds as Upcoming Antigiardial Agents: In Vitro Action of Carvacrol, Thymol and p-Cymene on Giardia lamblia Trophozoites"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2900-6097","authenticated-orcid":false,"given":"Marisa","family":"Machado","sequence":"first","affiliation":[{"name":"UCIBIO\u2014Applied Molecular Biosciences Unit, Translational Toxicology Research Laboratory, University Institute of Health Sciences (1H-TOXRUN, IUCS-CESPU), 4585-116 Gandra, Portugal"},{"name":"Associate Laboratory i4HB\u2014Institute for Health and Bioeconomy, University Institute of Health Sciences\u2014CESPU, 4585-116 Gandra, Portugal"},{"name":"H<sup>2<\/sup>M\u2014Health and Human Movement Unit, Instituto Polit\u00e9cnico de Sa\u00fade do Norte, Cooperativa de Ensino Superior Polit\u00e9cnico e Universit\u00e1rio (CESPU), CRL, 4760-409 Vila Nova de Famalic\u00e3o, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0880-2959","authenticated-orcid":false,"given":"Ana","family":"Silva","sequence":"additional","affiliation":[{"name":"H<sup>2<\/sup>M\u2014Health and Human Movement Unit, Instituto Polit\u00e9cnico de Sa\u00fade do Norte, Cooperativa de Ensino Superior Polit\u00e9cnico e Universit\u00e1rio (CESPU), CRL, 4760-409 Vila Nova de Famalic\u00e3o, Portugal"},{"name":"Unidade Multidisciplinar de Investiga\u00e7\u00e3o Biom\u00e9dica (UMIB), Instituto de Ci\u00eancias Biom\u00e9dicas Abel Salazar (ICBAS), Universidade do Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"},{"name":"ITR\u2014Laboratory for Integrative and Translational Research in Population Health, Rua das Taipas 135, 4050-600 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-7407-5261","authenticated-orcid":false,"given":"Rui","family":"Linhares","sequence":"additional","affiliation":[{"name":"H<sup>2<\/sup>M\u2014Health and Human Movement Unit, Instituto Polit\u00e9cnico de Sa\u00fade do Norte, Cooperativa de Ensino Superior Polit\u00e9cnico e Universit\u00e1rio (CESPU), CRL, 4760-409 Vila Nova de Famalic\u00e3o, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5937-1127","authenticated-orcid":false,"given":"Carlos","family":"Cavaleiro","sequence":"additional","affiliation":[{"name":"Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal"},{"name":"Chemical Process Engineering and Forest Products Research Centre (CIEPQPF), University of Coimbra, Rua S\u00edlvio Lima, 3030-790 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4957-7831","authenticated-orcid":false,"given":"Maria C.","family":"Sousa","sequence":"additional","affiliation":[{"name":"Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal"},{"name":"Center for Neurosciences and Cell Biology (CNC), University of Coimbra, 3004-504 Coimbra, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"134","DOI":"10.2174\/1872213X13666190618124901","article-title":"Giardiasis: An Overview","volume":"13","author":"Leung","year":"2019","journal-title":"Recent Pat. 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