Highest Oxygen Radical Absorbance Capacity Value Research Articles

Antioxidant properties of prunes (Prunus domestica L.) and their constituents

Prunes contain large amounts of phenolics and show high antioxidant activity. The aim of this study is to clarify the contents of caffeoylquinic acid (CQA) isomers, and to estimate the contribution of these isomers to the antioxidant activity of prunes. Furthermore, structural elucidation and evaluation of antioxidant activity of prune components were also performed. CQA isomers in prunes were quantified by HPLC analysis, and it has become apparent that prunes contain relatively high amount of 4-O-caffeoylquinic acid. The contribution of CQA isomers to the antioxidant activity of prunes was revealed to be 28.4% on the basis of oxygen radical absorbance capacity (ORAC); hence, it was indicated that residual ORAC is dependent on unknown antioxidant components. Total 28 compounds were isolated and their structures were elucidated by NMR and MS analyses. Four abscisic acid related compounds, a chromanon, and a bipyrrole were novel. Each CQA isomer in prunes showed high antioxidant activities when measured by the oil stability index (OSI) method, O2- scavenging activity, and ORAC. Other isolated compounds such as hydroxycinnamic acids, benzoic acids, coumarins, lignans, and flavonoid showed high ORAC values. Furthermore, a novel chromanon indicated a remarkable synergistic effect on ORAC of CQA isomers.

Oxygen Radical Absorbance Capacity (ORAC), Phenolic, and Anthocyanin Concentrations in Fruit and Leaf Tissue of Highbush Blueberry

Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in fruit tissue of 86 highbush blueberry cultivars, and ORAC and phenolic levels evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit = 1 micromole Trolox Equivalent), 1.79 mg·g–1 (gallic acid equivalents), and 0.95 mg·g–1 (cyanidin-3-glucoside equivalents), respectively. ëRubel' had the highest ORAC values, at 31.1 units. Values for ORAC and phenolics in leaf tissue were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.8 mg·g–1 in leaf tissue, respectively. No significant correlations were found between fruit ORAC and leaf ORAC, or between fruit ORAC and leaf phenolics. Investigation of ORAC values in a family of 44 `Rubel' × `Duke' seedlings showed negative epistasis for ORAC values. However, an analysis of ORAC values vs. pedigree in plants from the 86 cultivar groups suggested that across cultivars, ORAC inheritance is generally additive.

535 Oxygen Radical Absorbance Capacity (ORAC), Phenolic, and Anthocyanin Concentrations in Fruit and Leaf Tissue of Highbush Blueberry

Antioxidant capacity as measured by ORAC, total phenolic, and total anthocyanin concentrations were evaluated in leaf tissue of the same 86 highbush blueberry cultivars, and ORAC and phenolic levels evaluated in leaf tissue of the same materials. Average values for ORAC, phenolics, and anthocyanins in fruit were 15.9 ORAC units (1 unit = 1 μmol Trolox Equivalent), 1.79 mg/g (gallic acid equivalents), and 0.95 mg/g (cyanidin-3-glucoside equivalents), respectively. `Rubel' had the highest ORAC values, at 31.1 units. Values for ORAC and phenolics in leaf tissue were significantly higher than fruit tissue, with mean values of 490.4 ORAC units and 44.8 mg/g in leaf tissue, respectively. No significant correlations were found between fruit ORAC and leaf ORAC, or between fruit ORAC and leaf phenolics. Investigation of ORAC values in a family of 44 `Rubel' × `Duke' seedlings showed negative epistatis for ORAC values. However, an analysis of ORAC values vs. pedigree in plants from the 86 cultivar groups suggested that, across cultivars, ORAC inheritance in generally additive.