Tocopherols and tocotrienols: Sources, analytical methods, and effects in food and biological systems

Tocopherols and tocotrienols (alpha, gamma, beta, and gamma), also known as tocols, are natural liposoluble phenols. Their importance stems from their antioxidant and non-antioxidant functions. This contribution summarizes their common and emerging sources with focus on their (bio)chemical effects in food and under physiological conditions. In food systems, tocopherols and tocotrienols act mainly as antioxidants, whereas their lipid-soluble character makes them particularly important in human and animal tissues. The most common and novel analytical methods for their extraction from food materials, identification and quantification are also reported. Their antioxidant activity towards reactive oxygen species (ROS) has been well documented. Furthermore, tocols regulate several stages of inflammation, which explains the complexity involved in anticipating their potential health benefits. Therefore, the mechanisms of action of tocols by critically summarizing relevant in vitro and/or in vivo data are provided.