Effects of dietary phenolic compounds on tocopherol, cholesterol, and fatty acids in rats

Abstract

The effects of the phenolic compounds butylated hydroxytoluene (BHT), sesamin (S), curcumin (CU), and ferulic acid (FA) on plasma, liver, and lung concentrations of alpha- and gamma-tocopherols (T), on plasma and liver cholesterol, and on the fatty acid composition of liver lipids were studied in male Sprague-Dawley rats. Test compounds were given to rats ad libitum for 4 wk at 4 g/kg diet, in a diet low but adequate in vitamin E (36 mg/kg of gamma-T and 25 mg/kg of alpha-T) and containing 2 g/kg of cholesterol. BHT significantly reduced feed intake (P < 0.05) and body weight and increased feed conversion ratio; S and BHT caused a significant enlargement of the liver (P < 0.001), whereas CU and FA did not affect any of these parameters. The amount of liver lipids was significantly lowered by BHT (P < 0.01) while the other substances reduced liver lipid concentrations but not significantly. Regarding effects on tocopherol levels, (i) feeding of BHT resulted in a significant elevation (P< 0.001) of alpha-T in plasma, liver, and lung, while gamma-T values remained unchanged; (ii) rats provided with the S diet had substantially higher gamma-T levels (P < 0.001) in plasma, liver, and lung, whereas alpha-T levels were not affected; (iii) administration of CU raised the concentration of alpha-T in the lung (P < 0.01) but did not affect the plasma or liver values of any of the tocopherols; and (iv) FA had no effect on the levels of either homolog in the plasma, liver, or lung. The level of an unknown substance in the liver was significantly reduced by dietary BHT (P < 0.001). BHT was the only compound that tended to increase total cholesterol (TC) in plasma, due to an elevation of cholesterol in the very low density lipoprotein + low density lipoprotein (VLDL + LDL) fraction. S and FA tended to lower plasma total and VLDL + LDL cholesterol concentrations, but the effect for CU was statistically significant (P < 0.05). FA increased plasma high density lipoprotein cholesterol while the other compounds reduced it numerically, but not significantly. BHT, CU, and S reduced cholesterol levels in the liver TC (P < 0.001) and percentages of TC in liver lipids (P < 0.05). With regard to the fatty acid composition of liver lipids, S increased the n-6/n-3 and the 18:3/20:5 polyunsaturated fatty acids (PUFA) ratios, and BHT lowered total monounsaturated fatty acids and increased total PUFA (n-6 + n-3). The effects of CU and FA on fatty acids were not highly significant. These results suggest some in vivo interactions between these phenolic compounds and tocopherols that may increase the bioavailability of vitamin E and decrease cholesterol in rats.

Antioxidants and polyunsaturated fatty acids in multiple sclerosis

“…Aside from inhibition of lipid peroxidation, curcumin also decreased cholesterol levels in both the serum and brain tissue of mice (Soudamini et al, 1992). In rats, curcumin significantly decreased the total and very low-density lipoprotein (VLDL) and LDL cholesterol plasma concentrations (Kamal-Eldin et al, 2000).…”

“…The underlying mechanism may involve reduced intestinal uptake of cholesterol (Kamal-Eldin et al, 2000). It has been established that tocotrienol, a vitamin E isoform, also has hypocholesterolaemic properties through a mechanism different from HMG-CoA reductase inhibition (Theriault et al, 1999).…”

The Beneficial Effects of SesaVitaTM on Lipid Profiles and Blood Glucose Levels in Subjects With Prediabetes and Mild-To-Moderate Hyperlipidemia in India

“…A clinical study in hypercholesterolemic patients reported that daily oral intake of sesamin for 4 weeks significantly decreased total and LDL cholesterol concentrations (Hirata et al, 1996). Sesamin as a dietary supplement administered in hyperlipidemic rats reduced plasma and liver total cholesterol and LDL cholesterol concentrations (Kamal-Eldin et al, 2000). The hypocholesterolemic effect of sesamin is probably through inhibition of intestinal absorption of cholesterol, increased excretion of cholesterol into bile and decreased activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hirose et al, 1991).…”

Untitled

“…It also increases a-tocopherol level in rat plasma, suggesting in vivo interaction between curcumin and a-tocopherol. [71] The fatty acid content was found to increase after ethanol-induced liver damage is significantly decreased by curcumin treatment. [72] Curcumin causes the severity of pathological changes, and thus, it protects the damage of the heart from myocardial infarction.…”