Vitamin E Supplementation in Chemical Colorectal Carcinogenesis: A Two-Edged Knife

Cohen, Célia; Cardoso, João Felipe Rito; Garcia, Sérgio Britto; Vannucchi, Hélio

doi:10.3390/nu6083214

Cited by 8 publications

(7 citation statements)

References 45 publications

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“…In a similar study in AOM‐treated male BALB/c mice, however, γ‐T, but not γ‐TmT, (1 g/kg diet) suppressed moderate colitis‐promoted colon tumorigenesis, but neither agent was effective in inhibiting severe colitis and related colon tumorigenesis 105 . Interestingly, in a 1,2‐dimethylhydrazine‐induced colon cancer model in male Wistar rats, supplementation with a low dose of VE (α‐T) (225 IU, 3 times the RDI) had beneficial effects in reducing colon aberrant crypt foci (ACF) formation and COX2 expression, while a high dose of α‐T (1500 IU) did not 106 . A comparative study of the inhibitory activity of α‐T, γ‐T, and δ‐T (at 2 g/kg diet) was conducted in AOM‐treated Fischer 344 rats 107 .…”

Section: Laboratory Studies On Ve and Cancer Preventionmentioning

confidence: 99%

Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

Yang

Luo

Zeng

et al. 2020

Molecular Carcinogenesis

113

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α‐Tocopherol (α‐T) is the major form of vitamin E (VE) in animals and has the highest activity in carrying out the essential antioxidant functions of VE. Because of the involvement of oxidative stress in carcinogenesis, the cancer prevention activity of α‐T has been studied extensively. Lower VE intake or nutritional status has been shown to be associated with increased cancer risk, and supplementation of α‐T to populations with VE insufficiency has shown beneficial effects in lowering the cancer risk in some intervention studies. However, several large intervention studies with α‐T conducted in North America have not demonstrated a cancer prevention effect. More recent studies have centered on the γ‐ and δ‐forms of tocopherols and tocotrienols (T3). In comparison with α‐T, these forms have much lower systemic bioavailability but have shown stronger cancer‐preventive activities in many studies in animal models and cell lines. γ‐T3 and δ‐T3 generally have even higher activities than γ‐T and δ‐T. In this article, we review recent results from human and laboratory studies on the cancer‐preventive activities of different forms of tocopherols and tocotrienols, at nutritional and pharmacological levels. We aim to elucidate the possible mechanisms of the preventive actions and discuss the possible application of the available information for human cancer prevention by different VE forms.

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Section: Laboratory Studies On Ve and Cancer Preventionmentioning

confidence: 99%

Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

Yang

Luo

Zeng

et al. 2020

Molecular Carcinogenesis

113

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“…However, when AOM‐initiated carcinogenesis was promoted by relatively mild colitis induced by one cycle of DSS, γ‐T decreased tumor multiplicity demonstrating that γ‐T is able to alleviate moderate but not severe colitis‐promoted tumorigenesis . Administration of different doses of vitamin E in a 1, 2‐dimethylhydrazine induced model of colorectal carcinogenesis in male Wistar rats demonstrated that 1500 IU of vitamin E is hazardous, whereas 225 IU of vitamin E has beneficial effects on colorectal carcinogenesis associated with reduced aberrant crypt foci and decreased cyclooxygenase 2 expression . Investigation of the growth inhibitory effects of different forms of tocopherols, tocopherol phosphates, and tocopherol quinones on human colon cancer cells, HCT116 and HT29, revealed that tocopherol phosphates and tocopherol quinones had higher inhibitory activities than their parent compounds .…”

Section: Experimental Studies With Tocopherolsmentioning

confidence: 99%

Tocopherols in cancer: An update

Gupta

Suh

2016

Molecular Nutrition Food Res

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Tocopherols exist in four forms designated as α, β, δ and γ. Due to their strong antioxidant properties, tocopherols have been suggested to reduce the risk of cancer. Cancer prevention studies with tocopherols have mostly utilized α-tocopherol. Large scale clinical trials with α-tocopherol provided inconsistent results regarding the cancer preventive activities of tocopherols. This review summarizes our current understanding of the anti-cancer activities of different forms of tocopherols based on follow up of the clinical trials, recent epidemiological evidences and experimental studies using in vitro and in vivo models. The experimental data provide strong evidence in support of the anti-cancer activities of δ-tocopherol,γ-tocopherol and the natural tocopherol mixture rich in γ-tocopherol, γ-TmT, over α-tocopherol. Such outcomes emphasize the need for detailed investigation into the cancer preventive activities of different forms of tocopherols to provide a strong rationale for intervention studies in the future.

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“…Thus, the quantification of MDA content indicates the level of destruction of macromolecules as a direct result of lost cellular functions, which can eventually lead to death. 25,26 It has been demonstrated that environmental factors such as hydric stress can severely affect the accumulation of oxygen radicals and MDA in plants. [27][28][29][30] The lab practical presented here involves the 3-day experiment described below, which is aimed at teaching students from the advanced biochemistry course about certain antioxidant mechanisms that plants trigger in order to eliminate the excess generation of ROS produced in cells under drought stress.…”

Section: Introductionmentioning

confidence: 99%

“…This damage on cell membrane fatty acids generates small carbonyl compounds, including malondialdehyde (MDA), a cytotoxic product that can be used as a free radical level indicator. Thus, the quantification of MDA content indicates the level of destruction of macromolecules as a direct result of lost cellular functions, which can eventually lead to death 25,26 . It has been demonstrated that environmental factors such as hydric stress can severely affect the accumulation of oxygen radicals and MDA in plants 27–30 …”

Section: Introductionmentioning

confidence: 99%

A simple method to determine antioxidant status in aromatic plants subjected to drought stress

Chiappero

Cappellari

Palermo

et al. 2020

Biochem Molecular Bio Educ

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Drought is a major environmental stress factor that affects the growth and development of plants. All plants have to maintain the reactive oxygen species within certain levels for normal cellular homeostasis by means of their antioxidant systems, which can be classified as enzymatic and non-enzymatic. Plants under drought stress generate an excess production of reactive oxygen species. At high concentrations, this can be detrimental by producing damage to the protein structures and inhibiting enzymes, as well as oxidizing macromolecules, which may eventually lead to cell death. There has been increasing attention paid to the antioxidant capacity of aromatic/medicinal plants, with a high antioxidant content having been reported in some plant extracts, such as in Mentha piperita (peppermint). Peppermint plants cultivated under drought stress also present high levels of phenolic compounds, peroxidase enzyme activity and lipid peroxidation of membranes. A simple and inexpensive laboratory class is proposed for teaching some mechanisms that plants have evolved to avoid reactive oxygen species damage. The series of lab experiments described is aimed at demonstrating the antioxidant status in aromatic plants subjected to drought stress, by measuring total phenolic compound content (non-enzymatic antioxidant compound), peroxidase activity (enzymatic antioxidant) and malondialdehyde, as convenient biomarkers for lipid peroxidation. The proposed class will be carried out by undergraduate students of the advanced biochemistry course, as part of our biology and agronomy studies. The experiment presented is intended to be used as a vehicle to emphasize the concepts that students have learned in their lectures. This lab exercise to be carried out by the students has dual goals: to apply a methodology only learned superficially on previous courses, and also to increase their understanding of how plants developed resistance mechanisms in order to tolerate drought stress.

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Vitamin E Supplementation in Chemical Colorectal Carcinogenesis: A Two-Edged Knife

Cited by 8 publications

References 45 publications

Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

Tocopherols in cancer: An update

A simple method to determine antioxidant status in aromatic plants subjected to drought stress

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