Research progress of glutarimide-containing polyketides: Structures, bioactivities and their biosynthesis

Glutarimide-containing polyketides (GPs) are an important class of natural products with antifungal, antibacterial, antitumor and other biological activities. Generally, the structures have a six-membered ring of glutarimide (also known as 2,6-piperidinedione) and a polyketide side chain or a ring of varying lengths attached at C4 such as cycloheximide, 9-methylstreptimidone and migrastatin. Currently, at least 65 natural glutarimide antibiotics have been isolated and identified. The novel biosynthetic mechanism of the trans-AT PKS and multifaceted modes of action have promoted the progressive exploration of glutarimide-containing products. However, the related information on the aspects of new structure discovery, biological activity and biosynthesis of GPs is still not available. This review summarizes the current research from the aspects of new structure discovery, biological activity and biosynthesis, aiming to provide a reference for in-depth products mining and structure-activity relationship research. Special emphasis is placed on their potential as drug leads, particularly in cancer therapy, and the role of modern analytical techniques in their discovery and characterization.