The Potential Role of Tocotrienols Against Cardiovascular Diseases

Tocotrienols, a group of vitamin E molecules, are natural dietary compounds that are abundant in rice bran oil, palm oil, and annatto oil but are also found in unrefined cereal grains, wheat germ, rye, oat, barley, amaranth, safflower, and seeds of pumpkin, grape, and flax. Varied numbers and locations of methyl groups on the chromanol ring, yields four different tocotrienol forms of alpha (α), beta (β), delta (δ), or gamma (γ). Tocotrienols are powerful antioxidants that exert anti-inflammatory, anti-cancer, neuroprotective, and cholesterol lowering properties which are often not demonstrated by tocopherols, the other class of the vitamin E family. The Etiology of atherosclerosis, the major cause of cardiovascular disease (CVD), is strongly associated with chronic inflammation as well as an abnormal metabolism, regulation, and expression of cholesterol. Tocotrienols show strong potential to hinder fat oxidation and inflammation for protection of arterial walls from atherosclerotic damage. Studies have shown that tocotrienol supplementation can increase the efflux of low density lipoprotein (LDL) by inducing expression of LDL receptors. By suppressing the upstream transcriptional regulators of lipid homeostasis genes, tocotrienols can also reduce the endogenous synthesis of cholesterol, very low density lipoprotein (VLDL), and triglycerides. Additionally, these vitamers can stimulate ubiquitination and degradation of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) which is the rate-limiting enzyme of the cholesterol biosynthesis pathway. Pleiotropic properties of tocotrienols render these vitamins protective and therapeutic effects against many chronic diseases including cardiovascular diseases.