{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T03:23:39Z","timestamp":1790825019376,"version":"4.1.0"},"reference-count":33,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,7,22]],"date-time":"2021-07-22T00:00:00Z","timestamp":1626912000000},"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 a Tecnologia","doi-asserted-by":"publisher","award":["SAICT-POL\/23925\/2016"],"award-info":[{"award-number":["SAICT-POL\/23925\/2016"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation performed at atmospheric pressure without the addition of water or organic solvents that has been proposed as a green method for the extraction of essential oils from aromatic and medicinal herbs. In this work, SFME and the conventional techniques of steam distillation (SD) and hydrodistillation (HD) were compared with respect to the extraction and antioxidant and antimicrobial activities of Thymus mastichina essential oil. The main constituent of essential oils obtained using different methods was 1,8-cineole (eucalyptol). The results showed that the essential oils extracted by means of SFME in 30 min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained using conventional HD over 120 min. In addition, SFME generates less waste and less solvent, consumes less energy, and provides a higher yield for a shorter extraction time, which is advantageous for the extraction of the T. mastichina essential oil compared to SD. The antioxidant and antimicrobial activities of the T. mastichina essential oil obtained from either SFME or conventional extraction methods (SD or HD) showed a similar pattern. Large-scale experiments using this SFME procedure showed a potential industrial application.<\/jats:p>","DOI":"10.3390\/ph14080709","type":"journal-article","created":{"date-parts":[[2021,7,22]],"date-time":"2021-07-22T22:35:31Z","timestamp":1626993331000},"page":"709","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["Solvent-Free Microwave Extraction of Thymus mastichina Essential Oil: Influence on Their Chemical Composition and on the Antioxidant and Antimicrobial Activities"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3510-948X","authenticated-orcid":false,"given":"Andr\u00e9 R. T. S.","family":"Araujo","sequence":"first","affiliation":[{"name":"Research Unit for Inland Development (UDI), Polytechnic Institute of Guarda, Av. Dr. Francisco S\u00e1 Carneiro, 50, 6300-559 Guarda, Portugal"},{"name":"LAQV\/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandrine","family":"P\u00e9rino","sequence":"additional","affiliation":[{"name":"INRAE, UMR 408, GREEN Extraction Team, Avignon University, 84000 Avignon, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xavier","family":"Fernandez","sequence":"additional","affiliation":[{"name":"CNRS, ICN, Parc Valrose, Universit\u00e9 C\u00f4te d\u2019Azur, CEDEX 2, 06108 Nice, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cassandra","family":"Cunha","sequence":"additional","affiliation":[{"name":"Research Unit for Inland Development (UDI), Polytechnic Institute of Guarda, Av. Dr. Francisco S\u00e1 Carneiro, 50, 6300-559 Guarda, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7010-0619","authenticated-orcid":false,"given":"M\u00e1rcio","family":"Rodrigues","sequence":"additional","affiliation":[{"name":"Research Unit for Inland Development (UDI), Polytechnic Institute of Guarda, Av. Dr. Francisco S\u00e1 Carneiro, 50, 6300-559 Guarda, Portugal"},{"name":"CICS-UBI\u2014Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilh\u00e3, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6357-8115","authenticated-orcid":false,"given":"Maximiano P.","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"Research Unit for Inland Development (UDI), Polytechnic Institute of Guarda, Av. Dr. Francisco S\u00e1 Carneiro, 50, 6300-559 Guarda, Portugal"},{"name":"CICS-UBI\u2014Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilh\u00e3, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5608-021X","authenticated-orcid":false,"given":"Luisa","family":"Jordao","sequence":"additional","affiliation":[{"name":"Department of Environmental Health, Research and Development Unit, National Institute of Health Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7386-0330","authenticated-orcid":false,"given":"L\u00facia A.","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Sciences, FibEnTech\u2014Fiber Materials and Environmental Technologies, University of Beira Interior, Rua Marqu\u00eas de \u00c1vila e Bolama, 6201-001 Covilh\u00e3, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6114-3572","authenticated-orcid":false,"given":"Jesus","family":"Rodilla","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Sciences, FibEnTech\u2014Fiber Materials and Environmental Technologies, University of Beira Interior, Rua Marqu\u00eas de \u00c1vila e Bolama, 6201-001 Covilh\u00e3, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6832-3082","authenticated-orcid":false,"given":"Paula","family":"Coutinho","sequence":"additional","affiliation":[{"name":"Research Unit for Inland Development (UDI), Polytechnic Institute of Guarda, Av. Dr. Francisco S\u00e1 Carneiro, 50, 6300-559 Guarda, Portugal"},{"name":"CICS-UBI\u2014Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilh\u00e3, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1712-3969","authenticated-orcid":false,"given":"Farid","family":"Chemat","sequence":"additional","affiliation":[{"name":"INRAE, UMR 408, GREEN Extraction Team, Avignon University, 84000 Avignon, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"203","DOI":"10.3923\/rjmp.2012.203.213","article-title":"Medicinally potential plants of Labiatae (Lamiaceae) family: An overview","volume":"6","author":"Raja","year":"2012","journal-title":"Res. J. Med. Plant"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1017\/S1479262115000337","article-title":"AFLP assessment of the genetic relationships among 12 Thymus taxa occurring in Portugal","volume":"15","author":"Duarte","year":"2017","journal-title":"Plant Genet. Resour."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1016\/j.lwt.2010.07.008","article-title":"From famine plants to tasty and fragrant spices: Three Lamiaceae of general dietary relevance in traditional cuisine of Tr\u00e1s-os-Montes (Portugal)","volume":"44","author":"Barros","year":"2011","journal-title":"LWT-Food Sci. Technol."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Miguel, G., Guerrero, C., Rodrigues, H., Brito, J., Ven\u00e2ncio, F., Tavares, R., and Duarte, F. (2002). Effect of substrate on the essential oils composition of Thymus mastichina (L.) L. subsp. mastichina collected in Sesimbra region (Portugal). Natural Products in the New Millennium: Prospects and Industrial Application, Springer.","DOI":"10.1007\/978-94-015-9876-7_14"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1080\/10412905.2004.9698665","article-title":"Main components of the essential oils from wild portuguese Thymus mastichina (L.) L. ssp. mastichina in different developmental stages or under culture conditions","volume":"16","author":"Miguel","year":"2004","journal-title":"J. Essent. Oil Res."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Cutillas, A.-B.B., Carrasco, A., Martinez-Gutierrez, R., Tomas, V., and Tudela, J. (2018). Thymus mastichina L. essential oils from Murcia (Spain): Composition and antioxidant, antienzymatic and antimicrobial bioactivities. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0190790"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1046\/j.1472-765X.2003.01259.x","article-title":"Antimicrobial activity of essential oils isolated from Portuguese endemic species of Thymus","volume":"36","author":"Faleiro","year":"2003","journal-title":"Lett. Appl. Microbiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"110747","DOI":"10.1016\/j.fct.2019.110747","article-title":"Toxicological and pharmacological properties of essential oils of Calamintha nepeta, Origanum virens and Thymus mastichina of Alentejo (Portugal)","volume":"133","author":"Arantes","year":"2019","journal-title":"Food Chem. Toxicol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e1700006","DOI":"10.1002\/cbdv.201700006","article-title":"Chemical composition, antibacterial, antibiofilm and synergistic properties of essential oils from Eucalyptus globulus Labill. and seven mediterranean aromatic plants","volume":"14","author":"Vieira","year":"2017","journal-title":"Chem. Biodivers."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1111\/j.1468-3083.2004.00886.x","article-title":"Antifungal activity of Thymus oils and their major compounds","volume":"18","author":"Rodrigues","year":"2004","journal-title":"J. Eur. Acad. Dermatol. Venereol."},{"key":"ref_11","first-page":"1029","article-title":"Antioxidant, anti-inflammatory and anti-hyperglycaemic activities of essential oils from Thymbra capitata, Thymus albicans, Thymus caespititius, Thymus carnosus, Thymus lotocephalus and Thymus mastichina from Portugal","volume":"11","author":"Aazza","year":"2016","journal-title":"Nat. Prod. Commun."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2183","DOI":"10.1080\/14786419.2017.1278598","article-title":"Antioxidant activity and cholinesterase inhibition studies of four flavouring herbs from Alentejo","volume":"31","author":"Arantes","year":"2017","journal-title":"Nat. Prod. Res."},{"key":"ref_13","first-page":"35","article-title":"Antioxidant, anti-5-lipoxygenase and antiacetylcholinesterase activities of essential oils and decoction waters of some aromatic plants","volume":"6","author":"Albano","year":"2012","journal-title":"Rec. Nat. Prod."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1080\/10412905.2015.1064039","article-title":"Volatile fraction differences for Lamiaceae species using different extraction methodologies","volume":"27","author":"Sponza","year":"2015","journal-title":"J. Essent. Oil Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"494","DOI":"10.1002\/ffj.1829","article-title":"Comparison of different isolation methods of essential oil from Citrus fruits: Cold pressing, hydrodistillation and microwave \u2018dry\u2019 distillation","volume":"22","author":"Ferhat","year":"2007","journal-title":"Flavour Fragr. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1080\/10412905.2012.751555","article-title":"Comparison of microwave-assisted distillation and conventional hydrodistillation in the essential oil extraction of flowers Rosa damascena Mill","volume":"25","author":"Mohamadi","year":"2013","journal-title":"J. Essent. Oil Res."},{"key":"ref_17","unstructured":"Chemat, F., Lucchesi, M.E., and Smadia, J. (2004). Solvent-Free Microwave Extraction of Volatile Natural Substances. (No 10\/751,988), U.S. Patent Application."},{"key":"ref_18","first-page":"135","article-title":"Solvent-free microwave extraction: An innovative tool for rapid extraction of essential oil from aromatic herbs and spices","volume":"39","author":"Lucchesi","year":"2004","journal-title":"J. Microw. Power Electromagn. Energy"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.foodchem.2013.10.139","article-title":"Solvent-free microwave extraction of essential oil from aromatic herbs: From laboratory to pilot and industrial scale","volume":"150","author":"Filly","year":"2014","journal-title":"Food Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"5077","DOI":"10.1016\/j.chroma.2009.04.084","article-title":"Eco-friendly and cleaner process for isolation of essential oil using microwave energy: Experimental and theoretical study","volume":"1216","author":"Farhat","year":"2009","journal-title":"J. Chromatogr. A"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Chenni, M., EI Abed, D., Rakotomanomana, N., Fernandez, X., and Chemat, F. (2016). Comparative study of essential oils extracted from egyptian basil leaves (Ocimum basilicum L.) using hydro-distillation and solvent-free microwave extraction. Molecules, 21.","DOI":"10.3390\/molecules21010113"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1016\/j.indcrop.2014.04.038","article-title":"Solvent-free microwave extraction of essential oil from pigeon pea leaves [Cajanus cajan (L.) Millsp.] and evaluation of its antimicrobial activity","volume":"58","author":"Qi","year":"2014","journal-title":"Ind. Crops Prod."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Vern\u00e8s, L., Vian, M., and Chemat, F. (2020). Ultrasound and microwave as green tools for solid-liquid extraction. Liquid-Phase Extraction, Elsevier.","DOI":"10.1016\/B978-0-12-816911-7.00012-8"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1080\/14620316.2003.11511631","article-title":"Essential oils of Portuguese Thymus mastichina (L.) L. subsp. mastichina grown on different substrates and harvested on different dates","volume":"78","author":"Miguel","year":"2003","journal-title":"J. Hortic. Sci. Biotechnol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"659","DOI":"10.1016\/S0305-1978(97)00046-X","article-title":"Composition and variability of the essential oils of Thymus species from section mastichina from Portugal","volume":"25","author":"Salgueiro","year":"1997","journal-title":"Biochem. Syst. Ecol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1168","DOI":"10.1080\/09540105.2017.1332010","article-title":"Herbicidal value of essential oils from oregano-like flavour species","volume":"28","year":"2017","journal-title":"Food Agric. Immunol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"8615","DOI":"10.3390\/ijms13078615","article-title":"Green extraction of natural products: Concept and principles","volume":"13","author":"Chemat","year":"2012","journal-title":"Int. J. Mol. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Chemat, F., and Cravotto, G. (2013). Microwave-Assisted Extraction for Bioactive Compounds, Springer US.","DOI":"10.1007\/978-1-4614-4830-3"},{"key":"ref_29","unstructured":"Adams, R.P. (2007). Identification of Essential Oil Components by Gas Chromatography\/Mass Spectrometry, Allured Publishing Corporation Carol Stream."},{"key":"ref_30","unstructured":"Boelens Aroma Chemical Information Service (1999). The Complete Database of Essential Oils. ESO 2000, BACIS."},{"key":"ref_31","unstructured":"Kondjoyan, N., and Berdagu\u00e9, J.L. (1996). A Compilation of Relative Retention Indices for the Analysis of Aromatic Compounds, \u00c9dition du Laboratoire Flaveur; INRA."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1946","DOI":"10.1002\/elps.201700397","article-title":"What is the best ethanol-water ratio for the extraction of antioxidants from rosemary? Impact of the solvent on yield, composition, and activity of the extracts","volume":"39","author":"Laguerre","year":"2018","journal-title":"Electrophoresis"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/S0076-6879(99)99017-1","article-title":"Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent","volume":"299","author":"Singleton","year":"1999","journal-title":"Methods Enzymol."}],"container-title":["Pharmaceuticals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/8\/709\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:33:28Z","timestamp":1760164408000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/8\/709"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,7,22]]},"references-count":33,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["ph14080709"],"URL":"https:\/\/doi.org\/10.3390\/ph14080709","relation":{},"ISSN":["1424-8247"],"issn-type":[{"value":"1424-8247","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,7,22]]}}}