ABSTRACT
Tocopherols and tocotrienols, which are collectively known as tocochromanols, belong to the group of vitamin E compounds and play a pivotal role as essential, fat-soluble nutrients that function as antioxidants in the human body. Humans, as well as other animals and nonphotosynthetic organisms, however, cannot synthesize their own vitamin E, and this must be obtained from food. The roles of vitamin E have been extensively studied and at present more than 32,000 papers on vitamin E are listed in databases such as PubMed. However, just over 700 from this list are related to tocotrienols. As a consequence of their importance for human health, the role of tocotrienols in plants is often overlooked. Obviously plants do not synthesize tocotrienols for the bene•t of humans and animals, but rather they may play a role in plant metabolism. However, the biological signi•cance of tocotrienols in plants is rather complex, at least more than that of tocopherols. While tocopherols are synthesized in all photosynthetic organisms and are found in chloroplasts playing a role in the protection of photosynthesis-derived reactive oxygen species (ROS), tocotrienols are not universally found within the plant kingdom. Hence, they can be considered secondary metabolites, not in the sense of performing a “secondary” nonessential function, but because they are present in some speci•c plant families and species only, and usually in seeds or other nonphotosynthetic tissues playing an important role. In this chapter, we will present a current overview about the occurrence, biosynthesis, and function of tocotrienols in plants.
