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Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids.
J UOEH. 2006 Mar 01; 28(1):1-12.JU

Abstract

A strong radical-scavenging activity against a stable radical compound, 1,1-diphenyl-2-picrylhydrazyl (DPPH) was found in the hot water extract of Japanese rice bran. When the extract was treated with ethanol, a dominant radical-scavenging activity was observed in the ethanol-soluble (ES) fraction in a dose-dependent manner, but a weak radical-scavenging activity was detected in the ethanol-precipitable (EP) fraction. Their activities were proportional to the amounts of phenolic substances in each fraction. The phenolic substances in the ES fraction were efficiently separated by Amberlite XAD column chromatography and high performance liquid chromatography using an ODS column. The four major phenolic acids (ferulic, para-coumaric, para-hydroxybenzoic and vanillic acids) and four minor phenolic acids (caffeic, gentisic, protocatechuic and syringic acids) were detected in the HPLC system. Among these phenolic acids, protocatechuic, caffeic, ferulic and gentisic acids showed relatively strong radical scavenging activities (EC50: 8, 9, 29 and 75 microM, respectively) compared with the control antioxidants such as ascorbic acid and alpha-tocopherol (EC50: 93 and 134 microM). Para-coumaric, syringic and vanillic acids exhibited weak but significant radical-scavenging activities (EC50: 780, 2640 and 3250 microM). However, para-hydroxybenzoic acid did not show any significant effects even at 5 mM. Furthermore, a simulated mixture combined with these phenolic acids in comparable amounts in the ES fraction showed slightly weak radical-scavenging activity compared with that of rice bran extract. However, all the phenolic acids detected in the ES fraction did not show significant antioxidant activities against hydroperoxide generation in lipid peroxidation compared with that of a typical antioxidant such as ascorbic acid, which was estimated by the alminum chloride method. These results suggest that Japanese rice bran has a potent radical-scavenging activity against DPPH radical and this activity is associated with some phenolic acids in the ES fraction. The significance of this finding is discussed from the viewpoint of the protective role of rice bran against oxygen radical-induced chronic diseases.

Authors+Show Affiliations

Department of Human Life Science, Osaka Kun-Ei Women's College, Sets City, Osaka 566-8501, Japan.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16541736

Citation

Okai, Yasuji, and Kiyoka Higashi-Okai. "Radical-scavenging Activity of Hot Water Extract of Japanese Rice Bran--association With Phenolic Acids." Journal of UOEH, vol. 28, no. 1, 2006, pp. 1-12.
Okai Y, Higashi-Okai K. Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids. J UOEH. 2006;28(1):1-12.
Okai, Y., & Higashi-Okai, K. (2006). Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids. Journal of UOEH, 28(1), 1-12.
Okai Y, Higashi-Okai K. Radical-scavenging Activity of Hot Water Extract of Japanese Rice Bran--association With Phenolic Acids. J UOEH. 2006 Mar 1;28(1):1-12. PubMed PMID: 16541736.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids. AU - Okai,Yasuji, AU - Higashi-Okai,Kiyoka, PY - 2006/3/18/pubmed PY - 2006/4/25/medline PY - 2006/3/18/entrez SP - 1 EP - 12 JF - Journal of UOEH JO - J. UOEH VL - 28 IS - 1 N2 - A strong radical-scavenging activity against a stable radical compound, 1,1-diphenyl-2-picrylhydrazyl (DPPH) was found in the hot water extract of Japanese rice bran. When the extract was treated with ethanol, a dominant radical-scavenging activity was observed in the ethanol-soluble (ES) fraction in a dose-dependent manner, but a weak radical-scavenging activity was detected in the ethanol-precipitable (EP) fraction. Their activities were proportional to the amounts of phenolic substances in each fraction. The phenolic substances in the ES fraction were efficiently separated by Amberlite XAD column chromatography and high performance liquid chromatography using an ODS column. The four major phenolic acids (ferulic, para-coumaric, para-hydroxybenzoic and vanillic acids) and four minor phenolic acids (caffeic, gentisic, protocatechuic and syringic acids) were detected in the HPLC system. Among these phenolic acids, protocatechuic, caffeic, ferulic and gentisic acids showed relatively strong radical scavenging activities (EC50: 8, 9, 29 and 75 microM, respectively) compared with the control antioxidants such as ascorbic acid and alpha-tocopherol (EC50: 93 and 134 microM). Para-coumaric, syringic and vanillic acids exhibited weak but significant radical-scavenging activities (EC50: 780, 2640 and 3250 microM). However, para-hydroxybenzoic acid did not show any significant effects even at 5 mM. Furthermore, a simulated mixture combined with these phenolic acids in comparable amounts in the ES fraction showed slightly weak radical-scavenging activity compared with that of rice bran extract. However, all the phenolic acids detected in the ES fraction did not show significant antioxidant activities against hydroperoxide generation in lipid peroxidation compared with that of a typical antioxidant such as ascorbic acid, which was estimated by the alminum chloride method. These results suggest that Japanese rice bran has a potent radical-scavenging activity against DPPH radical and this activity is associated with some phenolic acids in the ES fraction. The significance of this finding is discussed from the viewpoint of the protective role of rice bran against oxygen radical-induced chronic diseases. SN - 0387-821X UR - https://www.unboundmedicine.com/medline/citation/16541736/Radical_scavenging_activity_of_hot_water_extract_of_Japanese_rice_bran__association_with_phenolic_acids_ L2 - http://www.medicalonline.jp/meteo_linkout.php?issn=0387-821X&volume=28&issue=1&spage=1 DB - PRIME DP - Unbound Medicine ER -