Document Detail

Inhibition of xanthine oxidase by phytic acid and its antioxidative action.
MedLine Citation:
PMID:  14738912     Owner:  NLM     Status:  MEDLINE    
We examined if phytic acid inhibits the enzymatic superoxide source xanthine oxidase (XO). Half inhibition of XO by phytic acid (IC50) was about 30 mM in the formation of uric acid from xanthine, but generation of the superoxide was greatly affected by phytic acid; the IC50 was about 6 mM, indicating that the superoxide generating domain of XO is more sensitive to phytic acid. The XO activity in intestinal homogenate was also inhibited by phytic acid. However, it was not observed with intestinal homogenate that superoxide generation was more sensitive to phytic acid compared with the formation of uric acid as observed with XO from butter milk. XO-induced superoxide-dependent lipid peroxidation was inhibited by phytic acid, but not by myo-inositol. Reduction of ADP-Fe3+ caused by XO was inhibited by superoxide dismutase, but not phytic acid. The results suggest that phytic acid interferes with the formation of ADP-iron-oxygen complexes that initiate lipid peroxidation. Both phytic acid and myo-inositol inhibited XO-induced superoxide-dependent DNA damage. Mannitol inhibited the DNA strand break. Myo-inositol may act as a hydroxyl radical scavenger. The antioxidative action of phytic acid may be due to not only inhibiting XO, but also preventing formation of ADP-iron-oxygen complexes.
Sanae Muraoka; Toshiaki Miura
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Life sciences     Volume:  74     ISSN:  0024-3205     ISO Abbreviation:  Life Sci.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-01-23     Completed Date:  2004-03-09     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0375521     Medline TA:  Life Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  1691-700     Citation Subset:  IM    
Department of Biochemistry, Hokkaido College of Pharmacy, Katsuraoka-cho 7-1, Otaru 047-0264, Japan.
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MeSH Terms
Adenosine Diphosphate / analogs & derivatives*,  metabolism
Antioxidants / pharmacology*
DNA Damage
Iron Chelating Agents / metabolism
Lipid Peroxidation
Phytic Acid / pharmacology*
Rats, Wistar
Reactive Oxygen Species / metabolism
Superoxides / metabolism
Xanthine Oxidase / antagonists & inhibitors*,  metabolism
Reg. No./Substance:
0/Antioxidants; 0/Iron Chelating Agents; 0/Reactive Oxygen Species; 0/adenosine diphosphate-ferric chelate; 11062-77-4/Superoxides; 58-64-0/Adenosine Diphosphate; 83-86-3/Phytic Acid; EC Oxidase

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