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Potent antioxidative and antigenotoxic activity in aqueous extract of Japanese rice bran – association with peroxidase activity
Author(s) -
HigashiOkai Kiyoka,
Kanbara Keiko,
Amano Kanako,
Hagiwara Akiko,
Sugita Chie,
Matsumoto Norie,
Okai Yasuji
Publication year - 2004
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.1576
Subject(s) - antioxidant , chemistry , bran , peroxidase , biochemistry , food science , lipid peroxidation , linoleic acid , enzyme , organic chemistry , raw material , fatty acid
To estimate the preventive potential of Japanese rice bran ( Oryza sativa japonica) against the oxygen radical‐related chronic diseases such as cardio‐vascular diseases and cancer, antioxidative and antigenotoxic activities of the rice bran extracts were analyzed by using assay systems for lipid peroxidation and genotoxin‐induced umu gene expression. When effects of the rice bran extracts under different extraction conditions on hydroperoxide generation from auto‐oxidized linoleic acid were examined using aluminum chloride method, the water extract showed strong antioxidant activity, but the methanol and acetone extracts did not exhibit signicant activity. The water extract of rice bran was divided into the ethanol‐precipitable (EP) and supernatant fractions, and EP fraction showed the dominant antioxidant activity, but the supernatant fraction did not exhibit signicant antioxidant activity. When the effect of EP fraction on umu C gene expression in SOS response associated with DNA damage in Salmonella typhimurium (TA 1535/pSK 1002) induced by 3‐amino‐1,4‐dimethyl‐5H‐pyrido[4,3‐b]indole (Trp‐P‐1) was analyzed, it showed a dose‐dependent suppressive activity against Trp‐P‐1‐induced umu C gene expression. The bio‐chemical analisis of EP fraction indicates that the major antioxidative and antigenotoxic activity of EP fraction is associated with a proteinous component with the molecular weight of more than 30 KDa. As a possible active principle for the antioxidative and antigenotoxic activity in EP fraction, the strong activity of an oxygen radical‐scavenging enzyme, peroxidase was detected, and the puried horseradish peroxidase also caused the similar antioxidative and antigenotoxic activities. The signicance of this nding is discussed from theviewpoint of the preventive role of rice bran against oxygen radical‐related chronic diseases. Copyright © 2004 John Wiley & Sons, Ltd.