Polyketides as a source of chemical diversity

Polyketides constitute one of the major classes of natural biomolecules. Many of these polyketide compounds, or derivatives thereof, make up infamous phycotoxins such as those produced by dinoflagellates and cyanobacteria, which have adverse effects on human health. This chapter highlights recently unveiled biosynthetic mechanisms to generate highly diverse and complex polyketide-derived bio-molecules. Polyketides have a backbone based on repeating ketide units, which are composed of adjacent methylene and carbonyl functional groups. Polyether ladders have a molecular backbone that consists of all trans-fused cyclic ether rings, in which the ring size may vary between five and nine members. The polyether ladders, linear polyethers, macrolides, polypeptide polyketides and tetrahydropurines discussed here chapter illustrate the structural diversity amongst phycotoxins.