Reactivity of β‐carotene towards peroxyl radicals studied by laser flash and steady‐state photolysis

FEBS Letters

Mortensen, Alan¹  Skibsted, Leif H¹ 

[1] Food Chemistry, Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark

关键词: β-carotene;    Peroxyl radical;    Photolysis;    Laser flash photolysis;   

DOI  :  10.1016/S0014-5793(98)00382-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Peroxyl radicals, as model for peroxyl radicals formed during autoxidation of lipids, have been generated in three solvent systems (cyclohexane, tetrahydrofuran and tert-butanol/water) by steady-state and laser flash photolysis, and their reaction with β-carotene studied. Steady-state photolysis experiments showed that alkyl, alkoxyl and alkylperoxyl radicals all react with β-carotene. However, laser flash photolysis experiments indicated that the reaction with peroxyl radicals (second-order rate constant estimated to be less than 10⁶ M⁻¹ s⁻¹) is slower than with alkyl and alkoxyl radicals, and that β-carotene is hence a poor direct scavenger of peroxyl radicals. Scavenging of peroxyl radicals by β-carotene is suggested not to proceed via electron transfer but rather by adduct formation and/or hydrogen abstraction. For different phenoxyl radicals, differences in reactivity towards β-carotene seem to be correlated with standard reduction potential.

【 授权许可】

Unknown