Curcumin prevents the oxidation and lipid modification of LDL and its inhibition of prostacyclin generation by endothelial cells in culture

Low-density lipoprotein (LDL) was isolated from human plasma and oxidized by 5 μM copper sulfate for 4 h at 37 °C in the absence and presence of 1, 3, 5, 10, or 20 μM of curcumin. LDL oxidized in the absence of curcumin (oxLDL) showed an increased levels of conjugated dienes, lipid peroxides (TBARS) and lysolecithin (lysoPC) and a significant loss of polyunsaturated fatty acids (PUFA). LDL oxidized with 5 μM copper sulfate in the presence of curcumin caused a significant decrease of conjugated diene, lipid peroxides, lysoPC and significant increase of PUFA compared to oxLDL. These changes were dose dependent and reached a maximum at 5 μM curcumin. Incubation of human endothelial cells (EC) with 200 μg protein/ml of oxLDL caused a significant decrease of prostacyclin (PGI2) generation. LDL oxidized in presence of 5 μM curcumin did not show any inhibition of PGI2 generation compared to the control cells. These results indicate that curcumin is an effective chain-breaking antioxidant which prevents oxidation and lipid modification of LDL. The inhibition of oxLDL on PGI2 is considered a contributing factor in the pathogenesis of thrombosis and atherosclerosis. Curcumin supplementation could be an effective strategy in preventing LDL oxidation and its impact on atherosclerosis and lesion formation.