ChEBI: (+)-alpha-tocopherol is an alpha-tocopherol that has R,R,R configuration. The naturally occurring stereoisomer of alpha-tocopherol, it is found particularly in sunflower and olive oils. It has a role as an antioxidant, a nutraceutical, a vitamin, an antiatherogenic agent, an EC 2.7.11.13 (protein kinase C) inhibitor, an anticoagulant, an immunomodulator, an antiviral agent, a micronutrient and an algal metabolite. It is an enantiomer of a (-)-alpha-tocopherol.NCI Thesaurus (NCIt): d-Alpha-Tocopherol is a naturally-occurring form of vitamin E, a fat-soluble vitamin with potent antioxidant properties. Considered essential for the stabilization of biological membranes (especially those with high amounts of polyunsaturated fatty acids), d-alpha-Tocopherol is a potent peroxyl radical scavenger and inhibits noncompetitively cyclooxygenase activity in many tissues, resulting in a decrease in prostaglandin production. Vitamin E also inhibits angiogenesis and tumor dormancy through suppressing vascular endothelial growth factor (VEGF) gene transcription. (NCI04)NCI Thesaurus (NCIt): Tocopherol is a class of vitamin E compounds naturally found in many different sources, such as oils, nuts, and vegetables. Tocopherols have antioxidant activity.NCI Thesaurus (NCIt): Alpha-Tocopherol is the orally bioavailable alpha form of the naturally-occurring fat-soluble vitamin E, with potent antioxidant and cytoprotective activities. Upon administration, alpha-tocopherol neutralizes free radicals, thereby protecting tissues and organs from oxidative damage. Alpha-tocopherol gets incorporated into biological membranes, prevents protein oxidation and inhibits lipid peroxidation, thereby maintaining cell membrane integrity and protecting the cell against damage. In addition, alpha-tocopherol inhibits the activity of protein kinase C (PKC) and PKC-mediated pathways. Alpha-tocopherol also modulates the expression of various genes, plays a key role in neurological function, inhibits platelet aggregation and enhances vasodilation. Compared with other forms of tocopherol, alpha-tocopherol is the most biologically active form and is the form that is preferentially absorbed and retained in the body.