This review emphasizes the effects of tocotrienols on the risk factors for atherosclerosis, plaque instability and thrombogenesis, and compares these effects with tocopherol. Tocotrienols reduce serum lipids and raise serum HDL-C. Alpha-tocopherol, on the other hand, has no effect on serum lipids. Tocotrienols have greater antioxidant activity than tocopherols. Both reduce the serum levels of Creactive protein (CRP) and advanced glycation end products, and expression of cell adhesion molecules. The CRP-lowering effects of tocotrienols are greater than tocopherol. Tocotrienols reduce inflammatory mediators, δ-tocotrienol being more potent, followed by γ- and α-tocotrienol. Tocotrienols are antithrombotic and suppress the expression of matrix metalloproteinases. They suppress, regress and slow the progression of atherosclerosis, while tocopherol only suppresses, and has no effect on regression and slowing of progression of atherosclerosis. Tocotrienol reduces risk factors for destabilization of atherosclerotic plaques. There are no firm data to suggest that tocotrienols are effective in reducing the risk of cardiac events in established ischemic heart disease. Alpha-tocopherol is effective in primary prevention of coronary artery disease (CAD), but has no conclusive evidence that it has beneficial effects in patients with established ischemic heart disease. Tocotrienols are effective in reducing ischemia-reperfusion cardiac injury in experimental animals and has the potential to be used in patients undergoing angioplasty, stent implantation and aorto-coronary bypass surgery. In conclusion, experimental data suggest that tocotrienols have a potential for cardiovascular health, but long-term randomized clinical trials are needed to establish their efficacy in primary and secondary prevention of CAD.
Atherosclerosis, antioxidant, anti-inflammatory, antithrombogenic, coronary artery disease, lipids, tocopherol, tocotrienol, hepatocytes, chemokines
Department of Physiology, College of Medicine, University of Saskatchewan 107 Wiggins Road Saskatoon SK S7N 5E5.