Chemical Reactivities and Physical Effects in Comparison between Tocopherols and Tocotrienols: Physiological Significance and Prospects as Antioxidants

Yoshida, Yasukazu; Saito, Yoshiro; Jones, Leslie Sargent; Shigeri, Yasushi

doi:10.1263/jbb.104.439

Cited by 101 publications

(53 citation statements)

References 44 publications

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“…The treatment also reduced urinary albumin excretion, decreased kidney weight and reduced the thickness of the glomerular basement membrane [187]. Tocotrienol, a component of vitamin E that may accumulate more effectively in membranes than α-tocopherol [188], was shown to ameliorate experimental nephropathy in STZ-diabetic rats [189]. Pyridoxamine (PM), one of three natural forms of vitamin B6, was also reported to inhibit the Maillard reaction and PM application in diabetic nephropathy has now progressed to a phase III clinical trials.…”

Section: Other Anti-glycative Compoudsmentioning

confidence: 99%

Plant-Derived Agents with Anti-Glycation Activity

Odjakova¹,

Popova²,

Sharif³

et al. 2012

Glycosylation

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Section: Other Anti-glycative Compoudsmentioning

confidence: 99%

Plant-Derived Agents with Anti-Glycation Activity

Odjakova¹,

Popova²,

Sharif³

et al. 2012

Glycosylation

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“…It is also reported that human plasma levels of a-tocopherol but not g-tocopherol are increased in male adults and children by the apolipoprotein A5 1131T.C gene polymorphism (15,16). In mice, apoE4 mice have lower plasma a-tocopherol than apoE3 mice (17).a-Tocopherol and g-tocopherol, at equal molar concentrations, have a relatively similar capacity to scavenge reactive oxygen species (ROS) during lipid peroxidation in vitro and in cells (18,19) and a relatively similar capacity to inhibit activation of protein kinase B (Akt) in cancer cells in vitro (20). Thus, because a-tocopherol is 10-fold higher in tissues than g-tocopherol, there is 10-fold more total ROS scavenging by a-tocopherol than g-tocopherol.…”

mentioning

confidence: 99%

“…a-Tocopherol and g-tocopherol, at equal molar concentrations, have a relatively similar capacity to scavenge reactive oxygen species (ROS) during lipid peroxidation in vitro and in cells (18,19) and a relatively similar capacity to inhibit activation of protein kinase B (Akt) in cancer cells in vitro (20). Thus, because a-tocopherol is 10-fold higher in tissues than g-tocopherol, there is 10-fold more total ROS scavenging by a-tocopherol than g-tocopherol.…”

mentioning

confidence: 99%

Two Faces of Vitamin E in the Lung

Cook‐Mills

Abdala-Valencia

Hartert

2013

Am J Respir Crit Care Med

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Asthma and allergic lung disease occur as complex environmental and genetic interactions. Clinical studies of asthma indicate a number of protective dietary factors, such as vitamin E, on asthma risk. However, these studies have had seemingly conflicting outcomes. In this perspective, we discuss opposing regulatory effects of tocopherol isoforms of vitamin E, mechanisms for tocopherol isoform regulation of allergic lung inflammation, association of vitamin E isoforms with outcomes in clinical studies, and how the variation in global prevalence of asthma may be explained, at least in part, by vitamin E isoforms.Keywords: asthma; a-tocopherol; g-tocopherol; human; mouse Asthma and allergic lung disease occur as complex environmental and genetic interactions (1). The World Health Organization has reported that the prevalence of asthma from 1950 to the present has increased in many countries, including countries with high rates of asthma, intermediate rates of asthma, or low rates of asthma (2-4). The marked differences in rates of asthma within countries, in migrating populations, and over relatively short periods of time support an important role of the local environment, such as diet, in asthma inception. Prospective epidemiological studies, observational cross-sectional studies, and some randomized prevention trials have demonstrated the impact of a number of protective dietary factors, such as vitamin E, on asthma risk. However, these studies have had seemingly conflicting outcomes. We need to determine why there are low rates of allergic disease in developing countries and better understand the differences in diet and lifestyle that may really underpin allergic disease. One environmental change over the past 40 years has been an increase in the g-tocopherol isoform of vitamin E in the diet and in infant formulas (5, 6). We recently demonstrated that g-tocopherol increases allergic lung inflammation in mice (6)(7)(8). In this perspective, we discuss why we have yet to uncover the complex and potentially protective effects of isoforms of vitamin E on asthma in humans and in animal models of lung inflammation. We also review mechanisms for tocopherol isoform regulation of allergic lung inflammation in animals and discuss how the variation in global prevalence of asthma may be explained, at least in part, by country-specific plasma g-tocopherol differences.Vitamin E consists of natural isoforms and synthetic racemic isoforms. The eight natural isomers are d-a-, d-b-, d-g-, d-d-tocopherol and d-a-, d-b-, d-g-, d-d-tocotrienol. Plants synthesize the natural isoforms from tyrosine and chlorophyll (9). Then, these tocols are consumed in the diet from plant lipids. Mammals do not interconvert the tocopherol isoforms. The most abundant isoforms are a-tocopherol and g-tocopherol, which differ by one methyl group ( Figure 1A). There are approximately 10-fold higher tissue concentrations of a-tocopherol than g-tocopherol due to preferential transfer of a-tocopherol in the liver by a-tocopherol transfer protein and due to ...

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“…The free radical scavenging reactivity at pH 4-8 is in the order ␣-tocopherolϾ␤-tocopherolϭ␥-tocopherolϾ ␦-tocopherolϾtocol (18,30). Therefore, the antiproliferative effects of the four tocopherol isomers and tocol on HSCs and HSC-T6 cells appear to be different compared to their antioxidant activities.…”

Section: Discussionmentioning

confidence: 99%

Antiproliferative and Proapoptotic Effects of Tocopherol and Tocol on Activated Hepatic Stellate Cells

Yamaguchi

Mezaki

Miura

et al. 2011

J Nutr Sci Vitaminol

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Summary Activated hepatic stellate cells (HSCs) play crucial roles in liver fibrosis. In the course of liver injury, HSCs, which reside in perisinusoidal spaces and lose lipid droplets, morphologically change into a myofibroblastic phenotype and acquire an increased proliferation activity in what is known as the activated state. We have investigated therapeutic strategies for liver fibrosis by promoting spontaneous reversion or inducing apoptosis in activated HSCs. Vitamin E consists of four tocopherols and four tocotrienols, all of which are well-known antioxidants. In this study, the antiproliferative and proapoptotic effects of a tocol, which lacks methyl groups attached to the chromanol ring, and four tocopherols were investigated using activated HSCs. ␦ -Tocopherol and tocol exhibited relatively high proliferation inhibitory and proapoptotic abilities. However, they did not show proliferation inhibition ability on primary hepatocytes or HepG2 cells. Significant cell detachment was also observed in ␦ -tocopherol-and tocol-treated HSCs. Decreased protein expressions of ␣ -smooth muscle actin and ␤ 1 integrin were observed in a dose-dependent manner. These results indicate that ␦ -tocopherol and tocol induce anoikis in activated HSCs.

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Chemical Reactivities and Physical Effects in Comparison between Tocopherols and Tocotrienols: Physiological Significance and Prospects as Antioxidants

Cited by 101 publications

References 44 publications

Plant-Derived Agents with Anti-Glycation Activity

Plant-Derived Agents with Anti-Glycation Activity

Two Faces of Vitamin E in the Lung

Antiproliferative and Proapoptotic Effects of Tocopherol and Tocol on Activated Hepatic Stellate Cells

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