月见草
化学
DPPH
清除
色谱法
植物
食品科学
抗氧化剂
有机化学
生物
作者
Mahinda Wettasinghe,Fereidoon Shahidi
出处
期刊:Food Chemistry
[Elsevier]
日期:2000-07-01
卷期号:70 (1): 17-26
被引量:241
标识
DOI:10.1016/s0308-8146(99)00269-1
摘要
Crude extracts of meals of borage and evening primrose were prepared under optimum extraction conditions and were subjected to Sephadex LH-20 column chromatography. Six fractions from each of the crude extracts were obtained and their content of total, hydrophilic and hydrophobic phenolics determined. The crude extracts and their fractions [at 100 and 200 ppm as sinapic acid (for borage) or catechin (for evening primrose) equivalents] were investigated for their reactive-oxygen species- (ROS; H2O2, O2•-, •OH) and 2,2-diphenyl-1-picrylhydrazyl- (DPPH•) scavenging efficacies. Both types of crude extracts and their fractions exerted a concentration-dependent scavenging of ROS and DPPH•. At 200 ppm, borage crude extract and its fractions III, IV and V exhibited a 100% scavenging of H2O2 whereas evening primrose crude extract and its fraction III, at the same concentration, scavenged H2O2 completely. A complete quenching of O2•- was evident for assay media containing 200 ppm borage and evening primrose crude extracts/fractions with the exception of borage fraction V and evening primrose fraction I which showed about 75% quenching. At 200 ppm, borage and evening primrose crude extracts/fractions (except borage fractions I and III) exerted a complete quenching of •OH. Among the borage and evening primrose crude extracts/fractions investigated, only fraction VI of evening primrose, at 200 ppm, was able to completely quench DPPH•.
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