title: New series of avenanthramides in oat seed.
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.
authors.affiliation: a Faculty of Agriculture , Tottori University , Tottori , Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishihara
authors.forename: Kana
authors.initials: K
authors.lastname: Kojima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Yuya
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Nakajima
mesh_terms: D018554:Avena / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors*; D002109:Caffeic Acids / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification; D000432:Methanol; D010851:Picrates / Q000037:antagonists & inhibitors*; D010936:Plant Extracts / Q000737:chemistry; D011422:Propionates; D012639:Seeds / Q000737:chemistry*; D012997:Solvents; D013388:Succinimides / Q000737:chemistry; D062367:ortho-Aminobenzoates / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D001713:Biphenyl Compounds; D002109:Caffeic Acids; D003373:Coumaric Acids; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; D011422:Propionates; D012997:Solvents; D013388:Succinimides; D062367:ortho-Aminobenzoates; C004999:ferulic acid; C004931:1,1-diphenyl-2-picrylhydrazyl; C495469:p-coumaric acid; C040048:caffeic acid; D000432:Methanol
keywords: Avena sativa; anti-oxidant; avenanthramide; phytoalexin