Occurrence of melatonin and its precursors in wines marketed in Spain determined through a validated UHPLC-MS/MS method

Abstract

Melatonin (MEL) is a compound present in foods and fermented beverages such as wine and beer which has attracted the interest of many researchers due to its bioactive properties. MEL is synthetized by yeast during alcoholic fermentation. This article aims to develop and validate an analytical method by ultra-high-performance liquid chromatography coupled to mass spectrometry (UHPLC-MS/MS) to determine MEL and its related compounds (L-tryptophan, tryptamine, serotonin, tryptophol, N-acetylserotonin, 5-hydroxytryptophan, and indole-3-acetic acid) and secondly, to study its presence in wines in a total of 85 commercial Spanish wine samples (53 red and 32 white wines). The concentration of MEL in red wines is significantly higher (13.21–347.50 ng mL-1) than in white wines (1.35–230.57 ng mL-1). It is noteworthy that all wine samples are grouped according to the type of wine. This is the first time that a study of MEL precursors in a large sample of wines has been carried out contributing to expanding the knowledge of the chemical composition and bioactive potential of wines.