| Oxidation of low-density lipoprotein (LDL) is key to atherosclerosis and coronary heart disease development. Primary lipid oxidation products are conjugated dienes (CD) that degrade to low molecular weight substances that denature LDL protein, apoB-100, leading to atherosclerosis. The effect of catechin and alpha-tocopherol at different stages of LDL oxidation was studied. Both compounds delayed CD production when present at lipid oxidation initiation, promoted oxidation if added during the lag phase of lipid oxidation but had no effect if added later. The oxidation kinetics were unaffected by the time of antioxidant addition. Fourier transform infrared spectroscopy was used to study the apoB-100 protein stabilization, but produced inconclusive data. Oxygen radical absorption capacity (ORACFL) was used to determine the degree of antioxidant synergy between catechin and quercetin. However, they were antagonistic at ranges of 2-8 muM. Contrary to previous research, catechin ORACFL value was larger than that of quercetin. |
