Astaxanthin diferulate as a bifunctional antioxidant.
Astaxanthin when esterified with ferulic acid is better singlet oxygen quencher with k2 = (1.58 ± 0.1) 10(10) L mol(-1)s(-1) in ethanol at 25°C compared with astaxanthin with k2 = (1.12 ± 0.01) 10(9) L mol(-1)s(-1). The ferulate moiety in the astaxanthin diester is a better radical scavenger than free ferulic acid as seen from the rate constant of scavenging of 1-hydroxyethyl radicals in ethanol at 25°C with a second-order rate constant of (1.68 ± 0.1) 10(8) L mol(-1)s(-1) compared with (1.60 ± 0.03) 10(7) L mol(-1)s(-1) for the astaxanthin:ferulic acid mixture, 1:2 equivalents. The mutual enhancement of antioxidant activity for the newly synthetized astaxanthin diferulate becoming a bifunctional antioxidant is rationalized according to a two-dimensional classification plot for electron donation and electron acceptance capability.
['Papa|T B R|TB|', 'Pinho|V D|VD|', 'do Nascimento|E S P|ES|', 'Santos|W G|WG|', 'Burtoloso|A C B|AC|', 'Skibsted|L H|LH|', 'Cardoso|D R|DR|']
D000975:Antioxidants D002338:Carotenoids D003373:Coumaric Acids D010084:Oxidation-Reduction D018384:Oxidative Stress D024341:Xanthophylls
astaxanthin antioxidant antiradical carotenoid plant phenol