Tocotrienol and fatty acid composition of barley oil and their effects on lipid metabolism

Wang, Linji; Newman, Rosemary K.; Newman, C. W.; Jackson, Larry L.; Hofer, Petrea

doi:10.1007/bf01088091

Cited by 39 publications

(21 citation statements)

References 9 publications

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“…Mevalonic acid, the product of this reaction, is considered to be the rate-limiting substrate for the synthesis of cholesterol in the body (23). A decrease in serum total cholesterol, a response consistent with the tocotrienol-mediated down-regulation of HMG-CoA reductase activity, has been reported by a number of other investigators (24)(25)(26)(27)(28).…”

mentioning

confidence: 67%

Dose‐response impact of various tocotrienols on serum lipid parameters in 5‐week‐old female chickens

Thomas

Gapor

et al. 2006

Lipids

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The cholesterol-suppressive action of the tocotrienol-rich-fraction (TRF) of palm oil may be due to the effect of its constituent tocotrienols on beta-hydroxy-beta-methylglutaryl coenzyme A (HMG-CoA) reductase activity. The tocotrienols, modulate HMG-CoA reductase activity via a post-transcriptional mechanism. As a consequence small doses (5-200 ppm) of TRF-supplemented diets fed to experimental animals lower serum cholesterol levels. These findings led us to evaluate the safety and efficacy of large supplements of TRF and its constituents. Diets supplemented with 50, 100, 250, 500, 1000, or 2000 ppm of TRF, alpha-tocopherol, alpha-tocotrienol, gamma-tocotrienol, or 6-tocotrienol were fed to chickens for 4 wk. There were no differences between groups or within groups in weight gain, or in feed consumption at the termination of the feeding period. Supplemental TRF produced a dose-response (50-2000 ppm) lowering of serum total and LDL cholesterol levels of 22% and 52% (P < 0.05), respectively, compared with the control group. alpha-Tocopherol did not affect total or LDL-cholesterol levels. Supplemental alpha-tocotrienol within the 50-500 ppm range produced a dose-response lowering of total (17%) and LDL (33%) cholesterol levels. The more potent gamma and delta isomers yielded dose-response (50-2,000 ppm) reductions of serum total (32%) and LDL (66%) cholesterol levels. HDL cholesterol levels were minimally impacted by the tocotrienols; as a result, the HDL/LDL cholesterol ratios were markedly improved (123-150%) by the supplements. Serum triglyceride levels were significantly lower in sera of pullets receiving the higher supplements. The safe dose of various tocotrienols for human consumption might be 200-1000 mg/d based on this study.

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confidence: 67%

Dose‐response impact of various tocotrienols on serum lipid parameters in 5‐week‐old female chickens

Thomas

Gapor

et al. 2006

Lipids

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“…Compounds found in the unsaponifiable fraction of other vegetable oils have been demonstrated to lower serum cholesterol, and mechanisms have been proposed for their mode of action. For example tocotrienols, found in barley oil, lower the activity of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase [16,17], and gamma oryzanol, found in rice bran oil, reduces the absorption of cholesterol and increases the excretion of bile acids [18,19]. Further studies are required to identify the cholesterol-lowering component in CSO and to establish its mode of action.…”

Section: Resultsmentioning

confidence: 98%

Lipids and Tocopherols in Serum and Liver of Female Rats Fed Diets Containing Corn Oil or Cottonseed Oil

Radcliffe

Czajka-Narins

2006

Plant Foods Hum Nutr

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Growing female rats were fed diets containing either corn oil (CO) or cottonseed oil (CSO) to determine if the previously reported lowering effect of CSO versus CO on serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) was sex specific and to compare the effect of these two oils on serum and tissue concentrations of RRR-alpha-tocopherol (alpha-T) and RRR-gamma-tocopherol (gamma-T), the two major tocopherols in these oils. In a 4-week study, groups of rats (n = 10 each) were fed diets containing 100 g/kg of either CO or CSO. TC was lower for group CSO than group CO. Serum concentrations of HDL-C, non-HDL-C, triglycerides (TGs), as well as the TC/ HDL-C ratio and the hepatic concentrations of cholesterol and TGs, were unaffected by diet. For serum and liver, between-group differences were noted for the concentrations of alpha-T (where values were higher for group CSO) and gamma-T (where values were lower for group CSO). These differences reflected differences between the oils in their concentrations of these tocopherols. Thus, CSO has a lowering effect on TC for both sexes, but on HDL-C for male animals only; replacement of CO with CSO results in changes in tocopherol status.

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“…The hypocholesterolemic effect of α-T3 is due to the suppression of hydroxyl-β-methylglutaryl co-enzyme A reductase, the key enzyme of cholesterol synthesis [7,8]. Wang et al [9] postulated that the suppression of plasma total-and LDL-cholesterol in chicks fed diets supplemented with 10% barley oil was due to the high level (55.3 mg kg −1 ) of α-T3 in the oil. γ -T3 and δ-T3 are also reported to be hypocholesterolemic isomers in the vitamin E group [10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cultivar, Year Grown, and Cropping System on the Content of Tocopherols and Tocotrienols in Grains of Hulled and Hulless Barley

Ehrenbergerová

Belcrediová

Prýma

et al. 2006

Plant Foods Hum Nutr

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In a three-year period (2000-2002) total tocols (tocopherols and tocotrienols), content of vitamin E and its isomers (alpha-, beta+gamma-, delta-tocopherols and tocotrienols) were assessed in grain of 13 barley genotypes. The highest content of tocols (60.3-67.6 mg kg(-1)) and content of vitamin E (Vitamin E equivalent-18.0-20.1 mg kg(-1)) were determined in the waxy varieties Wanubet, Wabet, and Washonubet. Standard varieties, i.e. of a malting type (Krona and Kompakt), had statistically significantly lower content of tocols (49.9 and 53.6 mg kg(-1)) and vitamin E (15.7-16.1 mg kg(-1)) compared to the waxy varieties. The hulless waxy variety Washonubet had statistically significantly higher total content of tocols (67.6 mg kg(-1)) and alpha- tocotrienols isomer (42.1 mg kg(-1)) versus all other genotypes in the set. Chemical treatment and fertilization statistically significantly increased the content of tocols (by 4.7 mg kg(-1)), vitamin E (by 1.9 mg kg(-1)), isomer alpha-tocopherol (by 0.9 mg kg(-1)) and isomer alpha- tocotrienols (by 3.3 mg kg(-1)). The average values of alpha-tocopherols and alpha-tocotrienols in the set were 6.7 mg kg(-1) and 29.7 mg kg(-1), respectively. Some of the reciprocal lines created by us from the malting and waxy varieties are suitable for food use for high contents of all tocopherols and alpha-tocotrienols.

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Tocotrienol and fatty acid composition of barley oil and their effects on lipid metabolism

Cited by 39 publications

References 9 publications

Dose‐response impact of various tocotrienols on serum lipid parameters in 5‐week‐old female chickens

Dose‐response impact of various tocotrienols on serum lipid parameters in 5‐week‐old female chickens

Lipids and Tocopherols in Serum and Liver of Female Rats Fed Diets Containing Corn Oil or Cottonseed Oil

Effect of Cultivar, Year Grown, and Cropping System on the Content of Tocopherols and Tocotrienols in Grains of Hulled and Hulless Barley

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