Kinetic study of the quenching reaction of singlet oxygen by seven rice bran extracts in ethanol solution. Development of a singlet oxygen absorption capacity (SOAC) assay method. Issue 12 (2nd December 2015)

• Record Type: Journal Article
• Authors: Mukai, Kazuo; Ishikawa, Eri; Abe, Takumi; Ouchi, Aya; Nagaoka, Shin-ichi; Murata, Kazumasa; Miyazawa, Teruo; Nakagawa, Kiyotaka
• Is Part Of: Bioscience, biotechnology, and biochemistry. Volume 79:Issue 12(2015)
• Page Start: 2063
• Page End: 2072
• Publication Date: 2015-12-02
• Subjects: rice bran extract -- carotenoid -- singlet oxygen -- antioxidant activity -- reaction rate; Biotechnology -- Periodicals; Biochemistry -- Periodicals; 660.6
• DOI: 10.1080/09168451.2015.1069701
• Languages: English
• ISSNs: 0916-8451

Abstract

Abstract: Measurements of singlet oxygen ( 1 O2 ) quenching rates ( k Q ( S )) and the relative singlet oxygen absorption capacity (SOAC) values were performed for seven rice bran extracts 1–7, which contained different concentrations of antioxidants (AOs) (such as α-, β-, γ-, and δ-tocopherols and -tocotrienols, three carotenoids (lutein, β-carotene, and zeaxanthin), and γ-oryzanol), in ethanol at 35 °C using UV–vis spectrophotometry. The concentrations of four tocopherols and four tocotrienols, three carotenoids, and γ-oryzanol contained in the extracts were determined using HPLC-MS/MS, UV-HPLC, and UV–vis absorption spectroscopy, respectively. Furthermore, comparisons of k Q ( S ) (Obsd.) values observed for the above extracts 1–7 with the sum of the product { [AO- i ]} of the values obtained for each AO- i and the concentration ([AO- i ]) of AO- i contained in extracts 1–7 were performed. From the results, it has been ascertained that the SOAC method is applicable to general food extracts to evaluate their 1 O2 -quenching activity. Graphical abstract: : Measurements of the quenching rate ( k Q ) of singlet oxygen were performed for seven rice bran extracts in ethanol to evaluate their singlet oxygen quenching activity.