Identification and Determination of 1,3-Thiazinane-4-carboxylic Acid in Human Urine-Chromatographic Studies.

Justyna Piechocka,Rafał Głowacki,Natalia Litwicka

doi:10.3390/ijms23020598

Justyna Piechocka, Rafał Głowacki + Show 1 more

Open Access

https://doi.org/10.3390/ijms23020598

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Abstract

It is well established that homocysteine (Hcy) and its thiolactone (HTL) are reactive towards aldehydes in an aqueous environment, forming substituted thiazinane carboxylic acids. This report provides evidence that Hcy/HTL and formaldehyde (FA) adduct, namely 1,3-thiazinane-4-carboxylic acid (TCA) is formed in vivo in humans. In order to provide definitive proof, a gas chromatography–mass spectrometry (GC–MS) based method was elaborated to identify and quantify TCA in human urine. The GC–MS assay involves chemical derivatization with isobutyl chloroformate (IBCF) in the presence of pyridine as a catalyst, followed by an ethyl acetate extraction of the obtained isobutyl derivative of TCA (TCA-IBCF). The validity of the method has been demonstrated based upon United States Food and Drug Administration recommendations. The assay linearity was observed within a 1–50 µmol L−1 range for TCA in urine, while the lowest concentration on the calibration curve was recognized as the limit of quantification (LOQ). Importantly, the method was successfully applied to urine samples delivered by apparently healthy volunteers (n = 15). The GC–MS assay may provide a new analytical tool for routine clinical analysis of the role of TCA in living systems in the near future.

Highlights

Population aging is undoubtedly one of the most dominant phenomena of our century
The following sections of the article provide the reader with all necessary information regarding the development, validation, and in-study use of the gas chromatography– mass spectrometry (GC–MS) based method for the determination of the newly recognized metabolite of sulfur metabolism, namely thiazinane-4-carboxylic acid (TCA), in human urine
Only one piece of evidence can be found in the literature that suggests that facile formation of TCA may diminish toxic Hcy, Hcy thiolactone (HTL) and FA content in biofluids, providing a beneficial effect on human health

Summary

Introduction

Civilization diseases, to which neurodegenerative diseases, cardiovascular diseases (CVD) and metabolic disorders belong, among others, are increasing in global prevalence They seriously threaten developing nations as they are one of the most frequent causes of the morbidity and mortality of humans. It has been recognized that sulfur-containing compounds, to which homocysteine (Hcy) and its metabolite Hcy thiolactone (HTL) belong, and formaldehyde (FA) are implicated in a number of civilization diseases [1,2,3,4,5,6,7,8,9,10] Their excess has been recognized as either an initiator or a marker of serious pathogenic processes, despite the fact that Hcy, HTL and FA are found in living systems as normal products [2,11]. The possibility of the conversion of Hcy, HTL and FA into a relatively inert compound in vivo is not without practical consideration

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