Macrocyclic polyketides from microorganisms: structural diversities and bioactivities

Microorganisms are a seemingly inexhaustible source of bioactive secondary metabolites, which play a crucial role in discovering potential drug candidates and expanding the structural diversity of natural products. Polyketides are a large group of secondary metabolites mainly derived from microorganisms, harboring architecturally distinct scaffolds and diverse bioactivities. This review highlights the roles of macrocyclic polyketides isolated from bacteria and fungi, as well as their sources, structure diversity, and biological activities. Total 242 macrocyclic polyketides mainly reported in recent two decades were covered in this review, including 165 ones from bacteria and 77 ones from fungi. Their structures could be divided into macrolactams, macrolides in bacteria, and macrolides, polyesters in fungi. And these compounds displayed cytotoxic, antibacterial, antifungal, and also some other activities, such as antimalarial and antitrypanosomal activities.