Dietary phenolic acids and derivatives. Evaluation of the antioxidant activity of sinapic acid and its alkyl esters.
The action of sinapic acid and its alkyl esters as potential antioxidants has been investigated. For this purpose, a series of sinapic acid ester derivatives was synthesized and their antioxidant activities were evaluated using distinctive analytical methods, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and FRAP UV-vis methods and differential scanning calorimetry. The electron-donating activity and lipophilicity of these phenolic compounds were also evaluated. From the overall results it was concluded that alkyl ester sinapates (linear alkyl esters) present almost the same antioxidant activity, albeit slightly lower, exhibited by the parent compound (sinapic acid). Furthermore, the addition of an alkyl ester side chain has a positive effect on the partition coefficient of sinapic acid, improving its utility as an antioxidant in a more lipophilic medium. The data on the antioxidant activity obtained by different analytical methods correlated well with each other and have revealed interesting antioxidant data of alkyl esters of sinapic acid.
CIQ/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal.
Alexandra
A
Gaspar
Marta
M
Martins
Paulo
P
Silva
E Manuela
EM
Garrido
Jorge
J
Garrido
Omidreza
O
Firuzi
Ramin
R
Miri
Luciano
L
Saso
Fernanda
F
Borges
D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry*; D003373:Coumaric Acids / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D062385:Hydroxybenzoates / Q000737:chemistry*; D015394:Molecular Structure
D000975:Antioxidants; D003373:Coumaric Acids; D004952:Esters; D062385:Hydroxybenzoates; C073734:sinapinic acid; C017616:phenolic acid