Natural Sources of Apocarotenoids and Their Applications

Apocarotenoids are compounds that are derived from the oxidative cleavage of carotenoids. They are obtained naturally from plants, bacteria, algae, and fungi. Animals cannot synthesize carotenoids and only obtain apocarotenoids through their diet. Apocatotenoids fulfil important biological functions in all organisms that produce them. In plants, they provide colours to flowers, fruits, and seeds, and function as molecules that regulate growth and development. In animals, apocarotenoids have an important role in vision and have antioxidant properties that can prevent the onset of diseases. In fungi, apocarotenoids act as signalling molecules that induce sexual development and carotenogenesis. In bacteria, the function of apocarotenoids is still not very clear, but some evidence indicates that they can act as virulence agents. Apocaronoids are enzymatically synthesized by specific carotenoid cleavage dioxygenases (CCDs), an evolutionarily conserved family of non-heme iron enzymes that require oxygen for specific cleavage of double bonds in carotenoid skeletons. The activity of CCDs results in the great diversity of apocarotenoids with specific biological functions. In this chapter, we describe the biosynthesis steps and biological functions of the main apocarotenoids produced by animals, bacteria, fungi, and plants, as well as their current and future applications.