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Gamma delta tocotrienols reduce hepatic triglyceride synthesis and VLDL secretion.

Journal of atherosclerosis and thrombosis (2010-08-13)
N Zaiden, W N Yap, S Ong, C H Xu, V H Teo, C P Chang, X W Zhang, K Nesaretnam, S Shiba, Y L Yap
RÉSUMÉ

Present study aimed to elucidate the suppression of serum lipids by gamma- and delta-tocotrienol (γδT3). The lipid-lowering effects of γδT3 were investigated using HepG2 liver cell line, hypercholesterolemic mice and borderline-high cholesterol patients. In-vitro results demonstrated two modes of action. First, γδT3 suppressed the upstream regulators of lipid homeostasis genes (DGAT2, APOB100, SREBP1/2 and HMGCR) leading to the suppression of triglycerides, cholesterol and VLDL biosyntheses. Second, γδT3 enhanced LDL efflux through induction of LDL receptor (LDLr) expression. Treatment of LDLr-deficient mice with 1 mg/day (50 mg/kg/day) γδT3 for one-month showed 28%, 19% reduction in cholesterol and triglyceride levels respectively, whereas HDL level was unaltered. The lipid-lowering effects were not affected by alpha-tocopherol (αTP). In a placebo-controlled human trial using 120 mg/day γδT3, only serum triglycerides were lowered by 28% followed by concomitant reduction in the triglyceride-rich VLDL and chylomicrons. In contrast, total cholesterol, LDL and HDL remained unchanged in treated and placebo groups. The discrepancies between in-vitro, in-vivo and human studies may be attributed to the differential rates of post-absorptive γδT3 degradation and LDL metabolism. Reduction in triglycerides synthesis and transport may be the primary benefit caused by ingesting γδT3 in human.

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Description du produit

Supelco
δ-Tocotrienol, analytical standard
Sigma-Aldrich
D-δ-Tocotrienol, from rice, ≥65% (GC)