Objective: To evaluate the inhibitory effect of quercetin, rutin and puerarin on the LDL oxidation induced by Cu2+ and to investigate their action on the prevention and treatment of atherosclerosis.
Method: The serum LDL was isolated by the one step density gradient ultracentrifugation. The LDL oxidation was induced by Cu2+ in vitro for different time periods. Quercetin, rutin and puerarin at 5 micromol x L(-1) were added respectively, as the experimental groups, 3 hours before oxidation. The oxidation of LDL in experimental and control groups was identified by measuring A234, REM, TBARS and protein carbonyls content, and the values were compared between the two groups.
Result: (1) The values of A234, REM, TBARS and protein carbonyls formation increased gradually during LDL oxidation induced by Cu2+ in vitro. (2) During LDL oxidation induced by Cu2+ in vitro and incubation with each of quercetin, rutin and puerarin, the kinetic changes of A234, REM, TBARS and protein carbonyls formation showed lag phases of 2-6 h, 2 h and 2 h respectively, and the corresponding values for each of the agents treated group were reduced by 27.7%-49.6%, 24.1%-38.6%, 19.8%-34.3% and 36.4%-56.8%; 12.8%-39.3%, 15.7%-32.0%, 19.0%-28.1% and 12.8%-50.3%; and 3.3%-19.2%, 7.0%-22.5%, 19.5%-22.8% and 8.6%-47.0%, respectively.
Conclusion: These results suggest that quercetin, rutin and puerarin can substantially inhibit LDL oxidation, and quercetin has antioxidation ability stronger than rutin and puerarin.