Vitamin E (α-Tocopherol): A Comprehensive Monograph on its Chemistry, Pharmacology, and Clinical Utility

Section 1: Introduction and Molecular Profile

1.1. Overview and Discovery

Vitamin E is a collective term for a group of eight lipophilic, or fat-soluble, compounds that are essential for human health and possess distinctive antioxidant activities.[1] These eight compounds, known as vitamers, are divided into two classes: four tocopherols (α-, β-, γ-, and δ-tocopherol) and four tocotrienols (α-, β-, γ-, and δ-tocotrienol).[1] All forms are synthesized exclusively by photosynthetic organisms, including plants, algae, and cyanobacteria, and therefore must be obtained from dietary sources.[1]

The history of Vitamin E began in 1922, when researchers Herbert Evans and Katherine Bishop identified a previously unknown dietary component essential for reproduction in rats.[3] Initially designated "factor X," its absence led to fetal resorption.[6] Subsequent research established its identity as a vitamin, and the name "tocopherol" was derived from the Greek words

tokos (childbirth) and pheros (to bring forth).[8] Further investigations isolated and characterized the different forms, identifying α-tocopherol as the most biologically active vitamer in humans and the only form officially recognized to meet human requirements.[2] This specific focus on α-tocopherol has historically dominated research, although recent studies have shed light on the unique and potentially significant biological roles of the other seven vitamers.