Natural forms of vitamin E: metabolism, antioxidant, and anti-inflammatory activities and their role in disease prevention and therapy

Abstract

The Vitamin E family consists of four tocopherols and four tocotrienols. α-Tocopherol (αT) is the predominant form of vitamin E in tissues and its deficiency leads to ataxia in humans. However, results from many clinical studies do not support protective roles of αT in disease prevention in people with adequate nutrient status. On the other hand, recent mechanistic studies indicate that other forms of vitamin E such as γ-tocopherol (γT), δ-tocopherol (δT) and γ-tocotrienol (γTE) have unique antioxidant and anti-inflammatory properties that are superior to αT in prevention and therapy against chronic diseases. These vitamin E forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids and suppress pro-inflammatory signaling such as NF-κB and STAT3/6. Unlike αT, other vitamin E forms are significantly metabolized to carboxychromanols via cytochrome P-450 (CYP4F2)-initiated side-chain ω-oxidation. Long-chain carboxychromanols, esp.13’-carboxychromanols, are shown to have stronger anti-inflammatory effects than un-metabolized vitamins and may therefore contribute to beneficial effects of vitamin E forms in vivo. Consistent with mechanistic findings, animal and human studies show that γT and tocotrienols may be useful against inflammation-associated diseases. This review focuses on non-αT forms of vitamin E with respect to their metabolism, anti-inflammatory effects and mechanisms and in vivo efficacy in preclinical models as well as human clinical intervention studies.

Seeds of Opuntia spp. as a novel high potential by-product: Phytochemical characterization and antioxidant activity

“…These increased tocopherol levels might have been triggered due to a biochemical response to the high PUFA percentages, since tocopherols are recognized as effective lipophilic antioxidants (Jiang, 2014).…”

Comparable Function of γ-Tocopherols in Asthma Remission by Affecting Eotaxin and IL-4

“…More and more researchers recently are considering the possibility that this phenomenon may be due to the changing antioxidant intake and maladjusted dietary ratio [2]. Meanwhile, a great deal of attention has been focused on the fat-soluble dietary vitamin E, a protective dietary factor with desirable antioxi-of vitamin E such as gamma-tocopherols (γT) and tocotrienols (especially γTE) have desirable anti-inflammatory effects by inhibiting eicosanoids or suppressing NF-κB signaling pathways [8,9]. Moreover, the investigation of γT in the airway inflammation of various animal models has attracted significant attention [10].…”

Replacing soybean oil with increasing levels of soybean acid oil in diets of coturnix quails (Coturnix coturnix coturnix) and the effects on egg quality

“…Soybean presents considerable amounts of vitamin E, with 10.99 mg of α-tocopherol, 62.4 mg of γ-tocopherol, and 20.38 of δ-tocopherol per 100 grams of oil. Vitamin E is a powerful lipid soluble antioxidant and scavenges lipid peroxyl radicals by donating hydrogen from the phenolic group on the chromanol ring (Jiang 2014), thereby protecting cells from harmful oxygen-free radicals. However, to date, there is no 530 ALINE A.P.…”