Polyketideisoprenoid

Polyketideisoprenoid is a term used to describe natural products that combine polyketide-derived and isoprenoid-derived fragments. The term is often used interchangeably with meroterpenoids, a widely studied class of hybrid compounds that arise from the collaboration of polyketide synthase pathways with terpenoid biosynthesis.

Biosynthesis and structure of these hybrids typically involve two biosynthetic tracks. The polyketide portion is assembled by polyketide synthases from simple precursors such as acetyl-CoA and malonyl-CoA, forming diverse carbon backbones. The terpenoid portion derives from isoprenoid precursors IPP and DMAPP via the mevalonate or non-mevalonate pathways. Enzymes such as prenyltransferases, cyclases, and various tailoring enzymes link the two moieties and introduce further modifications, including oxidation, methylation, and lactonization, producing a wide array of ring systems and functional groups.

Occurrence and significance are broad: polyketideisoprenoids have been found in fungi, plants, and marine organisms. They often function as ecological chemicals for defense or signaling and have attracted attention for their potential pharmaceutical activities. Biological evaluations frequently report antimicrobial, antifungal, anti-inflammatory, antioxidant, and anticancer properties, among others. The structural diversity of these hybrids underpins a range of bioactivities and makes them important targets for natural product discovery and medicinal chemistry.

Chemically, these compounds exhibit motifs where polyketide backbones are linked to terpenoid-derived rings or side chains. They may feature lactones, epoxides, phenolic or enone functionalities, and various degrees of oxidation and methylation, reflecting extensive tailoring after the initial assembly.

See also: meroterpenoids, prenylated polyketides, terpenoids.