title: Effect of naringin supplementation on cholesterol metabolism and antioxidant status in rats fed high cholesterol with different levels of vitamin E.
abstract: Some bioflavonoids are potent antioxidants and have pharmacological effects similar to those of vitamin E. The interactive effect of naringin and vitamin E was studied with respect to cholesterol metabolism and antioxidant status. Naringin supplementation (0.1%, wt/wt) with comparable levels of vitamin E was given to rats with a high-cholesterol (1%, wt/wt) diet for 5 weeks. The amount of vitamin E included in naringin-free and naringin diets was a low (low-E) and a normal (normal-E) level. The naringin supplementation significantly lowered the concentrations of plasma cholesterol and triglyceride compared to the naringin-free group in low vitamin E-fed rats. HMG-CoA reductase activity was significantly lowered by naringin supplementation within both the low-vitamin E group (794.64 +/- 9.87 vs. 432.18 +/- 12.33 pmol/min/mg protein, mean +/- SE; p < 0.05) and normal-vitamin E group (358.82 +/- 11.4 vs. 218.22 +/- 9.47 pmol/min/mg protein, mean +/- SE; p < 0.05) compared to each of the naringin-free group. The HMG-CoA reductase activity was also significantly lowered by increased dietary vitamin E when compared within the naringin and naringin-free group, respectively. Neither dietary naringin nor vitamin E did significantly change the activities of hepatic antioxidant enzymes and plasma thiobarbituric acid-reactive substance level. These data indicate that naringin lowers the plasma lipid concentrations when the dietary vitamin E level is low. The HMG-CoA reductase-inhibitory effect of naringin was more potent when dietary vitamin E was at a normal level. These data may contribute to understanding the interactive effect of naringin and vitamin E on cholesterol biosynthesis in high-cholesterol-fed rats.
authors.affiliation: Department of Food Science and Nutrition, Kyungpook National University, 1370 Yank-Suk Dong Pak-Ku, 702-701, Taegu, Korea. mschoi@knu.ac.kr
authors.forename: M S
authors.initials: MS
authors.lastname: Choi
authors.forename: K M
authors.initials: KM
authors.lastname: Do
authors.forename: Y S
authors.initials: YS
authors.lastname: Park
authors.forename: S M
authors.initials: SM
authors.lastname: Jeon
authors.forename: T S
authors.initials: TS
authors.lastname: Jeong
authors.forename: Y K
authors.initials: YK
authors.lastname: Lee
authors.forename: M K
authors.initials: MK
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Bok
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D002784:Cholesterol / Q000096:biosynthesis / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D019587:Dietary Supplements; D004347:Drug Interactions; D044950:Flavanones; D005419:Flavonoids / Q000008:administration & dosage*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D002791:Cholesterol, Dietary; D044950:Flavanones; D005419:Flavonoids; D014810:Vitamin E; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; C005274:naringin