Formation, Stability, and Antioxidative Properties of 2-Methylthioproline and 2-Methylthioprolineglycine in Grape Wines

Thioprolines formed by reacting cysteine with reactive carbonyls have been demonstrated to possess antitumor, antioxidative, and hepatoprotective properties. Using our developed QuEChERS sample preparation in combination a liquid chromatography–tandem mass spectrometry coupled stable isotope-dilution method, we identified quantitated 2-methylthioproline (1) 2-methylthioprolinylglycine (2) grape wines. In particular, 2 was for the first time We further tested hypothesis that these adducts, despite originating from carcinogenic acetaldehyde condensing aminothiols, could serve as antioxidants protecting cells oxidative insults. Results showed human liver pretreated 1 or were more tolerant stress, indicated concentration-dependent increase cell viability under an H2O2-oxidative environment. It is believed compounds may contribute antioxidative properties of