earticle

영어

In this study, eight kinds of phenolic acid conjugated COSs were prepared by amide coupling reaction and conjugated onto COSs. The structures were confirmed by UV spectrum and 1H-NMR. The antioxidant properties of the Caffeic acid conjugated COS (CFA-COS) were evaluated using several in vitro models. CFA-COS, showed 81.6% scavenging activity against 2,2-diphenyl-1-picrylhydrazyl and 89.8% nitroxide scavenging activity at 400 μg/mL. CFA-COS was also showed higher reducing power compared to others. Furthermore, the results obtain from this study showed the double bond of cinnamic acid derivatives probably participates in stabilizing the radical by resonance. The electron withdrawing carboxylic group has been negative influence on the proton donating ability of the phenolic ring. In addition, the catechol structure substantially increased the antioxidant activity of the COS derivatives by two electron or hydrogen which were donated to free radical. Catechol was converted to quinon compounds by oxidation. Moreover, the increasing in methoxyl groups of phenolic ring structure substantially increased the electron or hydrogen donating activity of the compounds by further stabilizing the phenoxyl radicals. An overall view indicate that there had a aromatic substitution and the order effectiveness within class (benzoic and cinnamic) was 3,4-dihydroxyl (PTA and CFA) >3-hydroxyl-4,5- dimethoxy (SRA and SNA) >3-hydroxy-4-methoxy (VNA and FRA) >p-hydroxy (HBA, PCA). Furthermore, the CFA-COS also exhibited good cytocompatibility and effectively inhibited the formation of intracellular reactive oxygen species (ROS) in time- and dose-dependent manner in Chang liver cells.