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O 2 >‐DEPENDENT and ‐INDEPENDENT PHOTOOXIDATION OF QUERCETIN IN THE PRESENCE and ABSENCE OF RIBOFLAVIN and EFFECTS OF ASCORBATE ON THE PHOTOOXIDATION
Author(s) -
Takahama Umeo
Publication year - 1985
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1985.tb03551.x
Subject(s) - quercetin , chemistry , xanthine oxidase , xanthine , superoxide dismutase , riboflavin , superoxide , biochemistry , photochemistry , antioxidant , enzyme
— The self‐sensitized photooxidation of quercetin was not suppressed by superoxide dismutase (SOD), but suppressed by ascorbate. During the suppression of quercetin photooxidation, ascorbate was oxidized. These results suggest the reduction of oxidized quercetin to quercetin by ascorbate. Quercetin photooxidation in the presence of both riboflavin and EDTA was suppressed by SOD by about 90%. The result suggests the participation of O 2 ‐ in the photooxidation of quercetin. The participation of O 2 ‐ in the quercetin oxidation was confirmed by a xanthine‐xanthine oxidase system. Based on these results the physiological and pharmacological functions of quercetin are discussed.