[Inhibitory effect of quercetin, rutin and puerarin on LDL oxidation induced by Cu2+].
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.


METHODS
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.


RESULTS
(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.


CONCLUSIONS
These results suggest that quercetin, rutin and puerarin can substantially inhibit LDL oxidation, and quercetin has antioxidation ability stronger than rutin and puerarin.
Liu
Rui
R
Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China. liurui60@hotmail.com
Meng
Fang
F
Bai
Huai
H
Liu
Yu
Y
Tang
Cheng-Wei
CW
Liu
Bing-Wen
BW
D000975:Antioxidants / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D050050:Protein Carbonylation / Q000187:drug effects; D011794:Quercetin / Q000494:pharmacology*; D012431:Rutin / Q000494:pharmacology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013997:Time Factors
D000975:Antioxidants; D007529:Isoflavones; D008077:Lipoproteins, LDL; D017392:Thiobarbituric Acid Reactive Substances; D012431:Rutin; D003300:Copper; D011794:Quercetin; C033607:puerarin