Valentão Patrícia, Fernandes Eduarda, Carvalho Félix, Andrade Paula B, Seabra Rosa M, Bastos M Lourdes
CEQUP/ Serviço de Farmacognosia, Faculdade de Farmácia, Universidade do Porto, R. Aníbal Cunha, 4050-047 Porto, Portugal.
J Agric Food Chem. 2002 Aug 14;50(17):4989-93. doi: 10.1021/jf020225o.
Polyphenols are able to act as antioxidants by virtue of their hydrogen-donating and metal-chelating capacities. Cardoon (Cynara cardunculus L.) is a species containing considerable amounts of polyphenolic compounds, namely flavonoids and phenolic acids. This study examined the antioxidant activity of cardoon lyophilized infusion against superoxide radical, hydroxyl radical, and hypochlorous acid. Superoxide radical was generated either in an enzymatic system or nonenzymatically, and the scavenging ability was assessed by the inhibition of superoxide radical-induced reduction of nitroblue tetrazolium. Hydroxyl radical was generated by the Fe3+-EDTA/ascorbate Fenton system, and scavenging capacity was estimated by evaluating the inhibition of hydroxyl radical-induced deoxyribose degradation into thiobarbituric acid-reactive substances. Inhibition of hypochlorous acid-induced 5-thio-2-nitrobenzoic acid oxidation to 5,5'-dithiobis(2-nitrobenzoic acid) was used in order to test the hypochlorous acid scavenging activity.
多酚类物质凭借其供氢能力和金属螯合能力可充当抗氧化剂。刺菜蓟（Cynara cardunculus L.）是一种含有大量多酚类化合物（即黄酮类化合物和酚酸）的植物。本研究检测了刺菜蓟冻干浸液对超氧阴离子自由基、羟基自由基和次氯酸的抗氧化活性。超氧阴离子自由基可通过酶促系统或非酶促方式产生，其清除能力通过抑制超氧阴离子自由基诱导的硝基蓝四唑还原进行评估。羟基自由基由Fe3+-EDTA/抗坏血酸芬顿体系产生，清除能力通过评估抑制羟基自由基诱导的脱氧核糖降解为硫代巴比妥酸反应性物质来估算。为测试次氯酸清除活性，采用抑制次氯酸诱导的5-硫代-2-硝基苯甲酸氧化为5,5'-二硫代双（2-硝基苯甲酸）的方法。
