The main metabolites of caffeic and ferulic acids (ferulic acid-4′-O-sulfate, caffeic acid-4′-O-sulfate, and caffeic acid-3′-O-sulfate), the most representative phenolic acids in fruits and vegetables, and the acyl glucuronide of ferulic acid were synthesized, purified, and tested for their antioxidant activity in comparison with those of their parent compounds and other related phenolics. Both the ferric reducing antioxidant power (FRAP) assay and the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging method were used. Ferulic acid-4′-O-sulfate and ferulic acid-4′-O-glucuronide exhibited very low antioxidant activity, while the monosulfate derivatives of caffeic acid were 4-fold less efficient as the antioxidant than caffeic acid. The acyl glucuronide of ferulic acid showed strong antioxidant action. The antioxidant activity of caffeic acid-3′-O-glucuronide and caffeic acid-4′-O-glucuronide was also studied. Our results demonstrate that some of the products of phenolic acid metabolism still retain strong antioxidant properties. Moreover, we first demonstrate the ex vivo synthesis of the acyl glucuronide of ferulic acid by mouse liver microsomes, in addition to the phenyl glucuronide.

中文翻译：

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酚酸及其代谢物的抗氧化活性：阿魏酸和咖啡酸的硫酸盐衍生物以及阿魏酸的酰基葡萄糖醛酸化物的合成和抗氧化性能

咖啡酸和阿魏酸的主要代谢产物（阿魏酸4' - O-硫酸盐，咖啡酸4'- O-硫酸盐和咖啡酸3'- O-硫酸盐），水果和蔬菜中最具代表性的酚酸合成，纯化了阿魏酸的酰基葡糖醛酸苷，并与它们的母体化合物和其他相关的酚类化合物进行了比较，测试了它们的抗氧化活性。同时使用了三价铁还原抗氧化剂能力（FRAP）和2，2'-叠氮基双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基清除方法。阿魏酸-4' - O-硫酸盐和阿魏酸-4'- O-葡糖醛酸苷显示出非常低的抗氧化活性，而咖啡酸的单硫酸盐衍生物作为抗氧化剂的效率比咖啡酸低4倍。阿魏酸的酰基葡糖醛酸显示出很强的抗氧化作用。的抗氧化活性咖啡酸-3'- ö葡萄糖醛酸苷和咖啡酸-4'- ö葡萄糖醛酸苷也进行了研究。我们的结果表明，酚酸代谢的某些产品仍然保留了强大的抗氧化性能。而且，我们首先证明了除了苯基葡糖醛酸苷外，还可以通过小鼠肝脏微粒体离体合成阿魏酸的酰基葡糖醛酸苷。