Publisher Summary This chapter discusses ferric reducing/antioxidant power (FRAP) assay. The ferric reducing/antioxidant power (FRAP) assay is a recently developed, direct test of “total antioxidant power.” The FRAP assay is robust, sensitive, simple, and speedy and facilitates experimental and clinical studies investigating the relationship among antioxidant status, dietary habits, and risk of disease. Measurement of the total antioxidant power of fresh biological fluids—such as blood plasma—can be measured directly; the antioxidant content of various dietary agents can be measured objectively and reproducibly and their potential for improving the antioxidant status of the body investigated and compared. The FRAP assay is also sensitive and analytically precise enough to be used in assessing the bioavailability of antioxidants in dietary agents to help monitor longitudinal changes in antioxidant status associated with an increased intake of dietary antioxidants and to investigate the effects of disease on antioxidant status.

Ferric reducing/antioxidant power assay: direct measure of total antioxidant activity of biological fluids and modified version for simultaneous measurement of total antioxidant power and ascorbic acid concentration

The relationship between antioxidant activity and antimutagenicity of various tea extracts (green tea, pouchong tea, oolong tea, and black tea) was investigated. All tea extracts exhibited markedly antioxidant activity and reducing power, especially oolong tea, which inhibited 73.6% peroxidation of linoleic acid. Tea extracts exhibited a 65-75% scavenging effect on superoxide at a dose of 1 mg and 30 - 60% scavenging effect on hydrogen peroxide at a dose of 400 microgram. They scavenged 100% hydroxyl radical at a dosage of 4 mg except the black tea. Tea extracts also showed 50 - 70% scavenging effect on alpha, alpha-diphenyl-beta-picrylhydrazyl radical. The antioxidant activity and the scavenging effects on active oxygen decreased in the order semifermented tea > nonfermented tea > fermented tea. Tea extracts showed strong antimutagenic action against five indirect mutagens, i.e., AFB1, Trp-P-1, Glu-P-1, B[a]P, and IQ, especially oolong and pouchong teas. The antioxidant effect of tea extracts was well correlated to their antimutagenicity in some cases but varied with the mutagen and antioxidative properties.

Antioxidant activity of various tea extracts in relation to their antimutagenicity

Antioxidant and radical scavenging properties of curcumin.

A good number of abstracts and research articles (in total 74) published, so far, for evaluating antioxidant activity of various samples of research interest were gone through where 407 methods were come across, which were repeated from 29 different methods. These were classified as in vitro and in vivo methods. And those are described and discussed below in this review article. In the later part of this review article, frequency of in vitro as well as in vivo methods is analyzed with a bar diagram. Solvents are important for extracting antioxidants from natural sources. Frequency of solvents used for extraction is also portrayed and the results are discussed in this article. As per this review there are 19 in vitro methods and 10 in vivo methods that are being used for the evaluation of antioxidant activity of the sample of interest. DPPH method was found to be used mostly for the in vitro antioxidant activity evaluation purpose while LPO was found as mostly used in vivo antioxidant assay. Ethanol was with the highest frequency as solvent for extraction purpose.

Review on in vivo and in vitro methods evaluation of antioxidant activity.

Free-radical scavenging capacity and antioxidant activity of selected plant species from the Canadian prairies

グルコサミン塩酸塩を遊離形にし, 37℃インキュベーターで0日から30日間放置褐変した褐変グルコサミン (BGA) の抗酸化性, 還元力, 褐変度, アミノ糖の残存量, pH, 水分量, 全窒素量を, 放置0日から5日間は毎日, 以後5日間の間隔で30日間測定した。一方, 0, 15, 30日間放置褐変したBGAをセファデックスG-15で分画し, 抗酸化性, 還元力, 褐変度, pHについて測定して, 次のような結果を得た。1) 遊離グルコサミンは, 3日間放置後より白色粉末状から褐色ペースト状に急激な変化を示した。2) 最も強い抗酸化性は, 25日間と30日間放置褐変したBGAで認められた。3) BGAのリノール酸に対する抗酸化性は, 褐変度と深い関係を示した。4) 長く放置褐変したBGAは, 分子量が比較的高い領域の褐変生成物質と, 比較的低い領域の褐変生成物質に分画された。5) 長く放置褐変したBGAでは, 高分子の褐変生成物質のフラクションと, 低分子の褐変生成物質のフラクションの中間フラクションに抗酸化性を認めた。

Makoto Oyaizu

Papers

Studies on products of browning reaction--antioxidative activities of products of browning reaction prepared from glucosamine