{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T03:56:25Z","timestamp":1769572585792,"version":"3.49.0"},"reference-count":64,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,12,19]],"date-time":"2020-12-19T00:00:00Z","timestamp":1608336000000},"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":["UIDB\/50011\/2020"],"award-info":[{"award-number":["UIDB\/50011\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDP\/50011\/2020"],"award-info":[{"award-number":["UIDP\/50011\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["Portuguese National NMR Network (RNRMN)"],"award-info":[{"award-number":["Portuguese National NMR Network (RNRMN)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["SFRH\/BD\/119509\/2016"],"award-info":[{"award-number":["SFRH\/BD\/119509\/2016"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Metabolites"],"abstract":"<jats:p>Maintaining a salivary metabolic profile upon sample collection and preparation is determinant in metabolomics. Nuclear magnetic resonance (NMR) spectroscopy was used to identify metabolite changes during short-term storage, at room temperature (RT)\/4 \u00b0C\/\u221220 \u00b0C, and after sample preparation, at RT\/4 \u00b0C (mimicking typical clinical\/laboratory settings). Interestingly, significant metabolic inter-individual and inter-day variability were noted, probably determining sample stability to some extent. After collection, no changes were noted at \u221220 \u00b0C (at least for 4 weeks). RT storage induced decreases in methylated macromolecules (6 h); lactate (8 h); alanine (12 h); galactose, hypoxanthine, pyruvate (24 h); sarcosine, betaine, choline, N-acetyl-glycoproteins (48 h), while acetate increased (48 h). Less, but different, changes were observed at 4 \u00b0C, suggesting different oral and microbial status at different temperatures (with a possible contribution from inter-individual and inter-day variability), and identifying galactose, hypoxanthine, and possibly, choline esters, as potential general stability indicators. After preparation, addition of NaN3 did not impact significantly on saliva stabilization, neither at RT nor at 4 \u00b0C, although its absence was accompanied by slight increases in fucose (6.5 h) and proline (8 h) at RT, and in xylose (24 h) at 4 \u00b0C. The putative metabolic origins of the above variations are discussed, with basis on the salivary microbiome. In summary, after collection, saliva can be stored at RT\/4 \u00b0C for up to 6 h and at \u221220 \u00b0C for at least 4 weeks. Upon preparation for NMR analysis, samples are highly stable at 25 \u00b0C up to 8 h and at 4 \u00b0C up to 48 h, with NaN3 addition preventing possible early changes in fucose, proline (6\u20138 h), and xylose (24 h) levels.<\/jats:p>","DOI":"10.3390\/metabo10120515","type":"journal-article","created":{"date-parts":[[2020,12,21]],"date-time":"2020-12-21T04:12:01Z","timestamp":1608523921000},"page":"515","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Evaluation of Saliva Stability for NMR Metabolomics: Collection and Handling Protocols"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9460-1162","authenticated-orcid":false,"given":"Daniela","family":"Duarte","sequence":"first","affiliation":[{"name":"CICECO\u2014Department of Chemistry, Aveiro Institute of Materials, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"given":"Beatriz","family":"Castro","sequence":"additional","affiliation":[{"name":"CICECO\u2014Department of Chemistry, Aveiro Institute of Materials, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4669-8999","authenticated-orcid":false,"given":"Joana Leonor","family":"Pereira","sequence":"additional","affiliation":[{"name":"Dentistry Department, Faculty of Medicine, Institute of Paediatric and Preventive Dentistry, University of Coimbra, 3000-075 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8740-642X","authenticated-orcid":false,"given":"Joana Faria","family":"Marques","sequence":"additional","affiliation":[{"name":"GIBBO-Oral Biology and Biochemistry Research Group, CEMBDE-COCHRANE Portugal\u2014Faculty of Dental Medicine, Universidade de Lisboa, 1649-003 Lisboa, Portugal"}]},{"given":"Ana Lu\u00edsa","family":"Costa","sequence":"additional","affiliation":[{"name":"Dentistry Department, Faculty of Medicine, Institute of Paediatric and Preventive Dentistry, University of Coimbra, 3000-075 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3766-4364","authenticated-orcid":false,"given":"Ana M.","family":"Gil","sequence":"additional","affiliation":[{"name":"CICECO\u2014Department of Chemistry, Aveiro Institute of Materials, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1023\/A:1013713905833","article-title":"Metabolomics\u2013the link between genotypes and phenotypes","volume":"48","author":"Fiehn","year":"2002","journal-title":"Plant Mol. 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