Inhibition effect of ethyl acetate fraction of clove on Trp and Lys modification during LDL oxidation

Oxidative modification of Tryptophan ( Trp) and Lysine ( Lys) in apo B-100 of LDL is the important factor resulting in atherosclerosis ( AS) .In order to investigate the possible inhibition effect of Ethyl acetate fraction of clove ( EAFC) on Trp and Lys oxidative modification during LDL oxidation, the concentrations of Cu SO4 and LDL were firstly optimized, and then this inhibition effects of EAFC against oxidation were evaluated by using fluorescence as the main index in this paper. The results indicated that the concentrations of Cu SO4 and LDL were 1.25, 25 μmol/L and 500 μg/m L respectively in subsequent experiments.Fluorescence quenching can be inhibited by 20 μg/m L EAFC, and this inhibition effect was significantly higher than that of the 1 μg/m L butylated hydroxytoluene ( positive control, BHT) ( p < 0.01) .Likewise, 3 μg/m L EAFC can inhibit the modification of Lys residues by highly reactive aldehydes.10 μg/m L EAFC can dramatically inhibit covalent binding of 4-HNE with the Lys residues ( p < 0.01) . The modification of Lys residues resulting from MDA was inhibited by EAFC ( 15 μg/m L) which was significant than that of 1 μg/m L BHT.Meanwhile, 15 μg/m L EAFC showed a significant inhibition on formation of lipofuscin ( p < 0.01) .This study provides references for further analyzing the inhibition way of EAFC and the mechanism thatEAFC inhibits the recognition between ox-LDL and scavenger receptors.