05.01.01
In diabetic patients, the excessive glycosylation of proteins and low-density lipoproteins is associated with markedly increased superoxide, hydrogen peroxide and hydroxyl radical production, which will cause extensive cellular and tissue damage including vascular injury4-5. Altered cellular metabolism caused by hyperglycemia has been suggested to play an important role in increasing the risk of cardiovascular, renal, ophthalmic and neurological complications of diabetes mellitus1-3. As such, people with diabetes may avoid or delay the heart and blood vessel disease by controlling these other risk factors. Palm tocotrienol complex plays an important role in the controlling these risk factors, i.e., as a potent scavenger of free radicals, in lowering of total serum cholesterol and preventing increased blood pressure in diabetic patients.
Vitamin E compounds are well known for their antioxidant properties6. The term vitamin E is now considered to be the generic name describing both the tocopherols and tocotrienols. However, tocopherols and tocotrienols are distinguished by their side chain. While tocopherol has a saturated phytyl tail, tocotrienol possesses an unsaturated isoprenoid side chain. Tocotrienols, like tocopherols, are capable of scavenging and quenching reactive oxygen species, also known as free radicals. Their antioxidative activity, however, resides mainly with its "chain-breaking" property, which neutralizes peroxyl and alkoxyl radicals generated during lipid peroxidation. In a double-blind crossover study, researchers found that palm tocotrienol complex significantly reduced lipid peroxidation and peroxide levels in 32 non-insulin dependent diabetes mellitus patients7.
For many years, alpha-tocopherol was generally considered the most potent antioxidant against lipid peroxidation in the vitamin E group. Recently, however, there has been considerable discrepancy in its relative antioxidant effectiveness when compared to other isomers. Alpha-tocotrienol was also found to be a better antioxidant than alpha-tocopherol. Notably, researchers at the University of Berkeley observed a remarkably higher antioxidant activity (40-60 times) with tocotrienol against lipid peroxidation in rat liver microsomes than with alpha-tocopherol8.
Kamat and Devasagayam9,10 observed similar results with palm tocotrienol complex in rat brain mitochondria and noted a stronger effect with delta-tocotrienol. Delta-tocotrienol, with the least steric hindrance to the hydroxyl-group (-OH) on the chromanol ring, has the highest antioxidant potency.
A number of case-controlled human trials were conducted to investigate the role of tocotrienols on blood cholesterol levels11,12,13. These studies used palm tocotrienol capsules, which were administered to hypercholesterolemic subjects. Patients assigned to the palm tocotrienol complex group received four capsules daily, each containing a mixture of alpha-tocopherol and alpha, gamma and delta-tocotrienol. Those receiving palm tocotrienol supplementation after a controlled dietary regimen experienced significant drops of 15-20% in plasma total cholesterol. The major reduction in cholesterol occurred in the LDL fraction, whereas HDL-cholesterol remained essentially unchanged. As it is important to control the blood cholesterol level in diabetes mellitus patients, palm tocotrienol complex may be proved to beneficial among diabetics.
1. Brownlee M, et al., Nonenzymatic glycosylation and the pathogenesis of diabetic complications, Ann. Intern. Med, 1984; 01: 527-537.
2. Brownee M, et al., Advanced glycosylation end-products in tissue and the biochemical basis of diabetic complications, New Eng. J. Med, 1988; 318: 1315-1321.
3. Nathan DM, Long-term complications of diabetic mellitus, New Eng. J. Med, 1993; 328: 1676-1685.
4. Lyons TJ, Oxidised low density lipoproteins: a role in the pathogenesis of atherocleosis in diabetes, Diabetic Med, 1991; 8: 411-419.
5. Epstein FH, Beyond cholesterol. Modifications of low-density lipoprotein that increase its atherogenicity, New Eng. J. Med, 1989; 320: 915-924.
6. Kamal-Eldin A, Appelqvist LA. The chemistry and antioxidant properties of tocopherols and tocotrienols. Lipids 1996; 31: 671-701.
7. Wan Nazaimoon WM, et al. Effects of palm olein tocopherol and tocotrienol on lipid peroxidation, lipid profiles and glycemic control in non-insulin diabetes mellitus patients, Nutrition Research, 1996; 16: 1901-1911.
8. Serbinova E, Kagan V, Han D, Packer L. Free radical recycling and intramembrane mobility in the antioxidant properties of a-tocopherol and a-tocotrienol. Free Radic Biol Med 1991; 10: 263-275.
9. Suzuki YJ, Tsuchiya M, Wassall SR, et al. Structural and dynamic membrane properties of a-tocopherol and a-tocotrienol: implications to the molecular mechanism of their antioxidant potency. Biochemistry 1993; 32: 10692-10699.
10. Kamat JP, Devasagayam TPA. Tocotrienols from palm oil as potent inhibitors of lipid peroxidation and protein oxidation in rat brain mitochondria. Neuro Lett 1995; 195: 179-82.
11. Qureshi AA, Qureshi N, Wright JJK, et al. Lowering of serum cholesterol in hypercholesterolemic humans by tocotrienols (palmvitee). Am J Clin Nutr 1991; 53: 1021S-1026S.
12. Qureshi AA, Bradlow BA, Brace L, et al. Response of hypercholesterolemic subjects to administration of tocotrienols. Lipids 1995; 30: 1171-1177.
13. Qureshi AA, Bradlow BA, Salser WA, Brace LD. Novel tocotrienols of rice bran modulate cardiovascular disease risk parameters of hypercholesterolemic humans. Nutr Biochem 1997; 8: 290-298.
Vitamin E compounds are well known for their antioxidant properties6. The term vitamin E is now considered to be the generic name describing both the tocopherols and tocotrienols. However, tocopherols and tocotrienols are distinguished by their side chain. While tocopherol has a saturated phytyl tail, tocotrienol possesses an unsaturated isoprenoid side chain. Tocotrienols, like tocopherols, are capable of scavenging and quenching reactive oxygen species, also known as free radicals. Their antioxidative activity, however, resides mainly with its "chain-breaking" property, which neutralizes peroxyl and alkoxyl radicals generated during lipid peroxidation. In a double-blind crossover study, researchers found that palm tocotrienol complex significantly reduced lipid peroxidation and peroxide levels in 32 non-insulin dependent diabetes mellitus patients7.
For many years, alpha-tocopherol was generally considered the most potent antioxidant against lipid peroxidation in the vitamin E group. Recently, however, there has been considerable discrepancy in its relative antioxidant effectiveness when compared to other isomers. Alpha-tocotrienol was also found to be a better antioxidant than alpha-tocopherol. Notably, researchers at the University of Berkeley observed a remarkably higher antioxidant activity (40-60 times) with tocotrienol against lipid peroxidation in rat liver microsomes than with alpha-tocopherol8.
Kamat and Devasagayam9,10 observed similar results with palm tocotrienol complex in rat brain mitochondria and noted a stronger effect with delta-tocotrienol. Delta-tocotrienol, with the least steric hindrance to the hydroxyl-group (-OH) on the chromanol ring, has the highest antioxidant potency.
A number of case-controlled human trials were conducted to investigate the role of tocotrienols on blood cholesterol levels11,12,13. These studies used palm tocotrienol capsules, which were administered to hypercholesterolemic subjects. Patients assigned to the palm tocotrienol complex group received four capsules daily, each containing a mixture of alpha-tocopherol and alpha, gamma and delta-tocotrienol. Those receiving palm tocotrienol supplementation after a controlled dietary regimen experienced significant drops of 15-20% in plasma total cholesterol. The major reduction in cholesterol occurred in the LDL fraction, whereas HDL-cholesterol remained essentially unchanged. As it is important to control the blood cholesterol level in diabetes mellitus patients, palm tocotrienol complex may be proved to beneficial among diabetics.
References
1. Brownlee M, et al., Nonenzymatic glycosylation and the pathogenesis of diabetic complications, Ann. Intern. Med, 1984; 01: 527-537.
2. Brownee M, et al., Advanced glycosylation end-products in tissue and the biochemical basis of diabetic complications, New Eng. J. Med, 1988; 318: 1315-1321.
3. Nathan DM, Long-term complications of diabetic mellitus, New Eng. J. Med, 1993; 328: 1676-1685.
4. Lyons TJ, Oxidised low density lipoproteins: a role in the pathogenesis of atherocleosis in diabetes, Diabetic Med, 1991; 8: 411-419.
5. Epstein FH, Beyond cholesterol. Modifications of low-density lipoprotein that increase its atherogenicity, New Eng. J. Med, 1989; 320: 915-924.
6. Kamal-Eldin A, Appelqvist LA. The chemistry and antioxidant properties of tocopherols and tocotrienols. Lipids 1996; 31: 671-701.
7. Wan Nazaimoon WM, et al. Effects of palm olein tocopherol and tocotrienol on lipid peroxidation, lipid profiles and glycemic control in non-insulin diabetes mellitus patients, Nutrition Research, 1996; 16: 1901-1911.
8. Serbinova E, Kagan V, Han D, Packer L. Free radical recycling and intramembrane mobility in the antioxidant properties of a-tocopherol and a-tocotrienol. Free Radic Biol Med 1991; 10: 263-275.
9. Suzuki YJ, Tsuchiya M, Wassall SR, et al. Structural and dynamic membrane properties of a-tocopherol and a-tocotrienol: implications to the molecular mechanism of their antioxidant potency. Biochemistry 1993; 32: 10692-10699.
10. Kamat JP, Devasagayam TPA. Tocotrienols from palm oil as potent inhibitors of lipid peroxidation and protein oxidation in rat brain mitochondria. Neuro Lett 1995; 195: 179-82.
11. Qureshi AA, Qureshi N, Wright JJK, et al. Lowering of serum cholesterol in hypercholesterolemic humans by tocotrienols (palmvitee). Am J Clin Nutr 1991; 53: 1021S-1026S.
12. Qureshi AA, Bradlow BA, Brace L, et al. Response of hypercholesterolemic subjects to administration of tocotrienols. Lipids 1995; 30: 1171-1177.
13. Qureshi AA, Bradlow BA, Salser WA, Brace LD. Novel tocotrienols of rice bran modulate cardiovascular disease risk parameters of hypercholesterolemic humans. Nutr Biochem 1997; 8: 290-298.