New series of avenanthramides in oat seed |
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Authors: | Atsushi Ishihara Kana Kojima Takeshi Fujita Yuya Yamamoto Hiromitsu Nakajima |
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Affiliation: | 1. Faculty of Agriculture, Tottori University, Tottori, Japanaishihara@muses.tottori-u.ac.jp;3. Faculty of Agriculture, Tottori University, Tottori, Japan |
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Abstract: | 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. |
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Keywords: | Avena sativa avenanthramide anti-oxidant phytoalexin |
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