Bayati Mohammad, Poojary Mahesha M
Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
Food Chem. 2025 Feb 28;466:142208. doi: 10.1016/j.foodchem.2024.142208. Epub 2024 Nov 22.
Polyphenols are well-known for their antioxidant properties, but their prooxidative activity remain less understood. This study quantitatively examined the formation of hydrogen peroxide (HO) during the autooxidation of nine different polyphenols in model systems, investigating how it impacts protein oxidation and protein-polyphenol covalent adduct formation. Polyphenols (4 mM) generated HO in the range of 0.2-242 μM, depending on type of polyphenol, incubation time, temperature, and pH, but no clear relationship between polyphenol structure and HO production was observed. The presence of free amino acids and proteins (bovine serum albumin and β-lactoglobulin) inhibited HO formation, with Cys completely scavenging HO. Met was highly susceptible to oxidation with a 25-75% loss, forming methionine sulfoxide through a two-electron oxidation pathway. Trp and Tyr were oxidized to produce dioxindolyl-ʟ-alanine, kynurenine, 3,4-dihydroxyphenylalanine, N'-formylkynurenine, and 5-hydroxytryptophan in the nmol/mol-mmol/mol amino acid range. Furthermore, autoxidation of polyphenols resulted in >177 distinct amino acid/protein-polyphenol adducts as identified using LC-Orbitrap-MS/MS analysis.
多酚以其抗氧化特性而闻名，但其促氧化活性仍鲜为人知。本研究定量检测了模型系统中九种不同多酚自氧化过程中过氧化氢（HO）的形成，探究其如何影响蛋白质氧化以及蛋白质 - 多酚共价加合物的形成。多酚（4 mM）产生的HO浓度在0.2 - 242 μM范围内，这取决于多酚的类型、孵育时间、温度和pH值，但未观察到多酚结构与HO产生之间的明确关系。游离氨基酸和蛋白质（牛血清白蛋白和β - 乳球蛋白）的存在抑制了HO的形成，其中半胱氨酸能完全清除HO。蛋氨酸极易氧化，损失率为25 - 75%，通过双电子氧化途径形成甲硫氨酸亚砜。色氨酸和酪氨酸被氧化，在每摩尔氨基酸产生纳摩尔/摩尔 - 毫摩尔/摩尔范围内生成二氧吲哚基 - ʟ - 丙氨酸、犬尿氨酸、3,4 - 二羟基苯丙氨酸、N'-甲酰犬尿氨酸和5 - 羟基色氨酸。此外，使用LC - Orbitrap - MS/MS分析鉴定出多酚的自氧化导致了超过177种不同的氨基酸/蛋白质 - 多酚加合物。
