Ectoine belongs to the class of organic compounds known as alpha-amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Ectoine has been identified in urine (PMID: 22409530 ).
Zhang T, Creek DJ, Barrett MP, Blackburn G, Watson DG: Evaluation of coupling reversed phase, aqueous normal phase, and hydrophilic interaction liquid chromatography with Orbitrap mass spectrometry for metabolomic studies of human urine. Anal Chem. 2012 Feb 21;84(4):1994-2001. doi: 10.1021/ac2030738. Epub 2012 Feb 1. [PubMed:22409530 ]
Mair RD, Sirich TL, Plummer NS, Meyer TW: Characteristics of Colon-Derived Uremic Solutes. Clin J Am Soc Nephrol. 2018 Sep 7;13(9):1398-1404. doi: 10.2215/CJN.03150318. Epub 2018 Aug 7. [PubMed:30087103 ]