Assays for Hydrophilic and Lipophilic Antioxidant Capacity (oxygen radical absorbance capacity (ORACFL)) of Plasma and Other Biological and Food Samples

详细信息    查看全文

• 作者：Ronald L. Prior ; Ha Hoang ; Liwei Gu ; Xianli Wu ; Mara Bacchiocca ; Luke Howard ; Maureen Hampsch-Woodill ; Dejian Huang ; Boxin Ou ; and Robert Jacob
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2003
• 出版时间：May 21, 2003
• 年：2003
• 卷：51
• 期：11
• 页码：3273 - 3279
• 全文大小：89K
• 年卷期：v.51,no.11(May 21, 2003)
• ISSN：1520-5118

文摘

Methods are described for the extraction and analysis of hydrophilic and lipophilic antioxidants, usingmodifications of the oxygen radical absorbing capacity (ORAC_FL) procedure. These methods provide,for the first time, the ability to obtain a measure of "total antioxidant capacity" in the protein freeplasma, using the same peroxyl radical generator for both lipophilic and hydrophilic antioxidants.Separation of the lipophilic and hydrophilic antioxidant fractions from plasma was accomplished byextracting with hexane after adding water and ethanol to the plasma (hexane/plasma/ethanol/water,4:1:2:1, v/v). Lipophilic and hydrophilic antioxidants were efficiently partitioned between hexane andaqueous solvents. Conditions for controlling temperature effects and decreasing assay variabilityusing fluorescein as the fluorescent probe were validated in different laboratories. Incubation (37 Cfor at least 30 min) of the buffer to which AAPH was dissolved was critical in decreasing assayvariability. Lipophilic antioxidants represented 33.1 ± 1.5 and 38.2 ± 1.9% of the total antioxidantcapacity of the protein free plasma in two independent studies of 6 and 10 subjects, respectively.Methods are described for application of the assay techniques to other types of biological and foodsamples.Keywords: ORAC_FL; phenolics; antioxidant; free radical; lipophilic; hydrophilic; blueberry; fruit juices