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Xanthine oxidase inhibitory activity of alkyl gallates
Author(s) -
Masuoka Noriyoshi,
Nihei Kenichi,
Kubo Isao
Publication year - 2006
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200500250
Subject(s) - xanthine oxidase , chemistry , gallic acid , alkyl , febuxostat , superoxide , hydrogen peroxide , uric acid , xanthine , oxidase test , stereochemistry , enzyme , medicinal chemistry , biochemistry , organic chemistry , antioxidant , hyperuricemia
A series (C 1 –C 12 ) of alkyl gallates was examined for their effects on the activity of xanthine oxidase. Octyl (C 8 ), decyl (C 10 ), and dodecyl (C 12 ) gallates competitively inhibited uric acid formation generated by xanthine oxidase, and the inhibition increased upon increasing the alkyl chain length. Interestingly, neither menthyl nor bornyl gallates inhibited uric acid formation. These data indicate that the hydrophobic alkyl portion is associated with the xanthine‐binding site in the Mo‐binding domain. It is likely that the linear alkyl portion interacts with the hydrophobic domain close to the binding site, and the hydrophobic interaction is crucial to inhibit the xanthine oxidase reaction. On the other hand, all of gallic acid and its esters equally suppress superoxide anion generation catalyzed by xanthine oxidase at low concentration. The suppression is not due to scavenging activity of these gallates but due to reduction of xanthine oxidase by these gallates. The reduced enzyme catalyzes the reaction to generate hydrogen peroxide and uric acid.