9-cis-astaxanthin (10), and 13-cis-astaxanthin (11), were isolated from the reaction products of carotenoids with peroxynitrite. Our previous studies achieved for the first time the isolation of nitro derivatives from the reaction of astaxanthin with peroxynitrite. Here we identify the major remaining reaction products of this reaction and investigate the stabilities of the nitro astaxanthins.
Analysis of Palmitoyl Apo-astaxanthinals, Apo-astaxanthinones, and their Epoxides by UHPLC-PDA-ESI-MS
作者:Yannick Weesepoel、Harry Gruppen、Wouter de Bruijn、Jean-Paul Vincken
DOI:10.1021/jf503520q
日期:2014.10.22
Food products enriched with fatty acid-esterified xanthophylls may result in deviating dietary apo-carotenoids. Therefore, free astaxanthin and its mono- and dipalmitate esters were subjected to two degradation processes in a methanolic model system: light-accelerated autoxidation and hypochlorous acid/hypochlorite (HOCl/OCl-) bleaching. Reversed phase ultrahigh-performance liquid chromatography photodiode array with in-line electrospray ionization mass spectrometry (RP-UHPLC-PDA-ESI-MS) was used for assessment of degradation products. Apo-astaxanthinals and -astaxanthinones containing 3 (apo-9) to 10 (apo-8') conjugated double bonds were found upon autoxidation for all three types of astaxanthin (except free apo-8?-astaxanthinal). Fragmentation of [M + H](+) and [M + Na](+) parent masses of apo-astaxanthins from dipalmitate astaxanthin indicated palmitate esterification. Astaxanthin monopalmitate degradation resulted in a mixture of free and palmitate apo-astaxanthins. HOCl/OCl rapidly converted the astaxanthins into a mixture of epoxy-apo-9- and epoxy-apo-13-astaxanthinones. The palmitate ester bond was hardly affected by autoxidation, whereas for HOCl/OCl the ester bond of the apo-astaxanthin palmitoyl esters was degraded.
Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. IX. Synthese von (3<i>R</i>)-Hydroxyechinenon, (3<i>R</i>, 3′<i>R</i>)- und (3<i>R</i>, 3′<i>S</i>)-Adonixanthin, (3<i>R</i>)-Adonirubin, deren optischen Antipoden und verwandten Verbindungen
作者:Kurt Bernhard、Gerhard Englert、Hans Mayer、Robert K. Müller、August Rüttimann、Max Vecchi、Erich Widmer、Reinhard Zell
DOI:10.1002/hlca.19810640754
日期:1981.11.4
Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. IX. Synthesis of (3R)-Hydroxyechinenone, (3R, 3′R)- and (3R, 3′S)-Adonixanthin, (3R)-Adonirubin, Their Optical Antipodes and Related Compounds