Quercetin dihydrate and gallate supplements lower plasma and hepatic lipids and change activities of hepatic antioxidant enzymes in high cholesterol-fed rats.
This study was designed to test the lipid-lowering and antioxidant activity of two bioflavonoids, quercetin dihydrate and gallate. Four groups of rats were given a semisynthetic diet containing 10 g cholesterol/kg for six weeks. The control group received only a high-cholesterol diet, whereas the other three groups received a diet including 1 g lovastatin, 1 g quercetin dihydrate, or 1 g gallate/kg. The quercetin dihydrate and gallate supplements both significantly lowered the plasma lipid and hepatic cholesterol levels compared to those of the control. The hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity was significantly lowered by the quercetin dihydrate when compared to the other groups, while the hepatic acyl CoA: cholesterol acyltransferase (ACAT) activity was only significantly higher in the control group. The overall potential for antioxidant protection was significantly enhanced by the quercetin dihydrate and gallate supplements through lowering the plasma and hepatic thiobarbituric acid reactive substances (TBARS) levels and increasing the hepatic superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in high-cholesterol-fed rats. These results suggest that the supplementation of quercetin dihydrate and gallate promotes an increase in fecal sterols, which in turn leads to a decreased absorption of dietary cholesterol as well as lower plasma and hepatic cholesterol.
Bok
Song-Hae
SH
Korea Research Institute of Bioscience and Biotechnology, P.O. Box 115, Yusong, Taejon, 305-606, Korea.
Park
Sun-Young
SY
Park
Yong Bok
YB
Lee
Mi-Kyung
MK
Jeon
Seon-Min
SM
Jeong
Tae-Sook
TS
Choi
Myung-Sook
MS
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D005243:Feces / Q000737:chemistry; D005707:Gallic Acid / Q000008:administration & dosage*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008055:Lipids / Q000032:analysis / Q000097:blood*; D008099:Liver / Q000737:chemistry / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D011794:Quercetin / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D002785:Sterol O-Acyltransferase / Q000378:metabolism; D013261:Sterols / Q000032:analysis; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000975:Antioxidants; D002791:Cholesterol, Dietary; D008055:Lipids; D013261:Sterols; D017392:Thiobarbituric Acid Reactive Substances; D005707:Gallic Acid; D011794:Quercetin; D006903:Hydroxymethylglutaryl CoA Reductases; D002785:Sterol O-Acyltransferase