Effect of either gamma-tocotrienol or a tocotrienol mixture on the plasma lipid profile in hamsters

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 gamma-tocotrienol (86%,gamma-T3) or a mixture of tocotrienols (29.5% alpha-T3, 3.3% beta-T3, 41.4% gamma-T3, 0.1% delta-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 gamma-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 gamma-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 gamma-tocotrienol is a more potent agent than a mixture of tocotrienols. Copyright (C) 2002 S. Karger AG, Basel.