中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
TRANS-咖啡酸 | caffeic acid | 501-16-6 | C9H8O4 | 180.16 |
Avenanthramides are characteristic constituents of oat seeds. We analyzed the methanol extract of oat seeds by HPLC and detected three compounds 1, 2, and 3 eluted at retention times similar to avenanthramides. The three compounds were purified by column chromatography and HPLC. Spectroscopic analyses of 1, 2, and 3 suggested that they are amides of 4,5-dihydroxyanthranilic acid with caffeic, p-coumaric, and ferulic acids, respectively. Their identities were confirmed by comparing spectra and chromatographic behavior with compounds synthesized from 4,5-dihydroxyanthranilic acid and N-hyrdroxysuccinimide esters of hydroxycinnamic acids. LC-MS/MS analysis with multiple reaction monitoring showed that the amounts of 1, 2, and 3 were 16.5–26.9% of corresponding avenanthamides with 5-hydroxyanthranilic acid. Compounds 1, 2, and 3 showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the corresponding avenanthramides with 5-hydroxyanthranilic acid, indicating the involvement of 4,5-dihydroxyanthranilic acid moiety in the scavenging of DPPH radicals.
燕麦籽中的燕麦苷是其特有的成分。我们通过高效液相色谱法分析了燕麦籽的甲醇提取物,检测到三种化合物1、2和3,它们在保留时间上与燕麦苷相似。通过柱层析和高效液相色谱法纯化了这三种化合物。对1、2和3的光谱分析表明,它们分别是4,5-二羟基蒽醌酸与咖啡酸、对香豆酸和香草酸的酰胺。通过将4,5-二羟基蒽醌酸和羟基肉桂酸类的N-羟基琥珀酰亚胺酯合成的化合物与光谱和色谱行为进行比较,证实了它们的身份。多反应监测的LC-MS/MS分析表明,1、2和3的含量是相应燕麦苷的16.5-26.9%,这些燕麦苷含有5-羟基蒽醌酸。化合物1、2和3的2,2-二苯基-1-芘肼(DPPH)自由基清除活性比含有5-羟基蒽醌酸的相应燕麦苷更强,表明4,5-二羟基蒽醌酸基团参与了清除DPPH自由基的过程。