Effect of either Gamma-Tocotrienol or a Tocotrienol Mixture on the Plasma Lipid Profile in Hamsters

Abstract

Background/Aims: Tocotrienols has been shown to inhibit the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity; however, the published animal and human studies yield conflicting results. We investigated the effects of a 4-week dietary supplement of either γ-tocotrienol (86% γ-T3) or a mixture of tocotrienols (29.5% α-T3, 3.3% β-T3, 41.4% γ-T3, 0.1% δ-T3: mix-T3) on the plasma lipid profile in hamsters receiving a high fat diet. Methods: The hamsters were randomized into 7 groups: no treatment, 16 mg/day/kg BW simvastatin, 23, 58, 263 mg/day/kg BW γ-tocotrienol, and 39 or 263 mg/day/kg BW for the mixture of tocotrienols. Plasma lipid levels were measured after 2 and 4 weeks of treatment. Results: In all groups treated with tocotrienol total cholesterol levels were decreased, ranging from 7 to 23% after 2 weeks of treatment and from 7 to 15% after 4 weeks. Low-density lipoprotein plasma levels changed accordingly: a decline of 6–37% after 2 weeks and of 12–32% at the end of the study was observed. After 4 weeks of treatment, total cholesterol and low-density lipoprotein plasma levels were significantly reduced in the 263 mg/day/kg BW mixed tocotrienols and the 58 mg/day/kg BW and 263 mg/day/kg BW γ-tocotrienol groups when compared to the no treatment group. Plasma triglycerides and high-density lipoprotein levels did not change significantly. Conclusion: This study provides further evidence that tocotrienols lower total cholesterol and low density lipoprotein plasma levels in hamsters and that γ-tocotrienol is a more potent agent than a mixture of tocotrienols.

Dose‐response impact of various tocotrienols on serum lipid parameters in 5‐week‐old female chickens

“…The differences observed in the human studies were partly due to the use of various doses and sources of TRF and tocotrienols. In order to compare the results of animal and human studies, Raederstorff et al studied steady-state plasma γ-tocotrienol levels and plasma cholesterol levels in hamsters (50). They observed that the maximum effect of γ-tocotrienol was reached after 2 wk with the highest dose (263 mg/d/kg body weight); thereafter, the effect on cholesterol was plateaued.…”

Effects of Tocols Rich Fraction Isolated from Rice Bran Oil Deodorizer Distillate on Plasma and Hepatic Lipid Concentrations in Rats

“…Numerous studies reported that the effects of tocotrienols and tocotrienol-rich fractions on lipid metabolism in animals [26]- [29] and humans [30]- [33]. The mechanism of the hypocholesterolemic effect of tocotrienols was revealed as the suppression of 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity and inhibition of expression of HMGCoA reductase mRNA [21] [34].…”

Tocotrienols and its impact in cardiovascular health

“…41 Experimental data from the study of hamsters are in agreement. 42 What added to the interest in tocotrienol as a cholesterol-lowering nutrient in humans was a concurrent independent study reporting the hypocholesterolemic effects of palmvitee. 43 Each palmvitee capsule contained approximately 18, 42, and 240 mg of tocopherols, tocotrienols, and palm olein, respectively.…”