Gamma and delta tocotrienols reduce liver triglyceride synthesis and VLDL secretion. - GreenMedInfo Summary
Gamma delta tocotrienols reduce hepatic triglyceride synthesis and VLDL secretion.
J Atheroscler Thromb. 2010 Oct 27;17(10):1019-32. Epub 2010 Aug 10. PMID: 20702976
Davos Life Science Pte Ltd, Cardiovascular Research Laboratory Singapore, 16 Tuas South Street 5, Singapore.
AIM: Present study aimed to elucidate the suppression of serum lipids by gamma- and delta-tocotrienol (γδT3).
METHODS: The lipid-lowering effects ofγδT3 were investigated using HepG2 liver cell line, hypercholesterolemic mice and borderline-high cholesterol patients.
RESULTS: 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.
CONCLUSION: Reduction in triglycerides synthesis and transport may be the primary benefit caused by ingestingγδT3 in human.