biostudies-literatureUnknown5(40)Fracassetti DRiboflavin (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 oxidatioACS omega26220-26229https://www.ebi.ac.uk/biostudies/studies/S-EPMC7558052biostudies-literatureInvestigating the Role of Antioxidant Compounds in Riboflavin-Mediated Photo-Oxidation of Methionine: A ¹H-NMR Approach.PMC7558052Mastro MLimbo STirelli ARagg EMFracassetti DPellegrino LfalseInvestigating the Role of Antioxidant Compounds in Riboflavin-Mediated Photo-Oxidation of Methionine: A ¹H-NMR Approach.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 oxidatio2020-01-01T00:00:00Z2020 Oct2025-05-29T19:05:56.008Z2025-05-29T19:05:56.008ZS-EPMC75580523307314810.1021/acsomega.0c03845