1 Food Chemistry, Department of Food Science, Faculty of Science, Københavns Universitet2 University of São Paulo State3 Design and Consumer Behavior, Department of Food Science, Faculty of Science, Københavns Universitet4 Design and Consumer Behavior, Department of Food Science, Faculty of Science, Københavns Universitet
Abstract 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.
Free Radical Research, 2015, Vol 49, Issue 1, p. 102-111