Investigating the Role of Antioxidant Compounds in Riboflavin-Mediated Photo-Oxidation of Methionine: A ¹H-NMR Approach.

ABSTRACT: Riboflavin (RF) is a well-known photosensitizer, responsible for the light-induced oxidation of methionine (Met) leading to the spoilage of wine. An NMR approach was used to investigate the role of gallic acid (GA) and sulfur dioxide (SO₂) in the RF-mediated photo-oxidation of Met. Water solutions of RF and Met, with and without GA or SO₂, were exposed to visible light for increasing time in both air and nitrogen atmospheres. Upon light exposure, a new signal appeared at 2.64 ppm that was assigned to the S(O)CH₃ moiety of methionine sulfoxide. Its formation rate was lower in a nitrogen atmosphere and even lower in the presence of GA, supporting the ability of this compound in quenching the singlet oxygen. In contrast, SO₂ caused relevant oxidatio

SUBMITTER: Fracassetti D 

PROVIDER: S-EPMC7558052 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature