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.

A Review of Extraction and Analysis of Bioactives in Oat and Barley and Scope for Use of Novel Food Processing Technologies

“…The quantities of A1 varied from 40-132 μg/g among the 10 cultivars of oats tested. Recently a new series of AVs containing a 4,5-dihydroxyanthranilate moiety were purified using column chromatography and HPLC from oat seeds [61]. The structures of these AVs were elucidated by a LC-MS/MS analysis with multiple reaction monitoring.…”

“…Table 2 outlines a brief overview of the extraction techniques, associated health benefits and commercial availability of the various bioactive components present in oat and barley. [61]. Bound phenolics-20 h prolonged alkaline hydrolysis [51];…”

Phenolic amides (avenanthramides) in oats - a review

“…Fagerlund et al (2009) found that, compared with α-tocopherol, AVAs protected linoleic acid from oxidation initially to a smaller extent initially. Also, to prevent the oxidative reaction of unsaturated fatty acids, AVAs can easily be used in the food industry (Ishihara et al 2014) due to the radical scavenging effect (Singh et al 2013). Similarly, Liu et al (2011) studied the antioxidant ability of capsules containing oats AVAs on human body and found that oats extract containing AVAs possessed a high antioxidant activity on humans (Liu et al 2011).…”

“…It is interesting that AVAs are very similar in their chemical structure to tranilast (N-3,4-dimethoxycinnamoylanthranilic acid), which is an antiallergic drug used to treat asthma and autoimmune diseases (Azuma et al 1976;Ishihara et al 2014). AVAs, having a similar structure to that of tranilast, can be used in the treatment of allergic reactions (Sur et al 2008).…”

“…AVAs are generally determined by various chromatographic methods. For the determination of the AVAs amounts, highperformance liquid chromatography (HPLC) (Bryngelsson et al 2002;Peterson et al 2002;Chen et al 2004;Mattila et al 2005;Jastrebova et al 2006;Skoglund et al 2008;Wise et al 2011;Ortiz-Robledo et al 2013;Ishihara et al 2014;Koening et al 2014), liquid chromatography-mass spectrometry (LC-MS) (Okazaki et al 2004), liquid chromatography-mass/ mass spectrometry (LC-MS/MS) (Ishihara et al 2014), and ion-exchange chromatography (Collins 1989) have been used. HPLC currently represents the most popular technique for the analysis of AVAs.…”