Discovery, bioactivities and biosynthesis of spirooxindole alkaloids.

Covering: up to the end of August, 2025Spirooxindole-containing natural products are widely distributed in actinomycetes, cyanobacteria, fungi, plants, and invertebrates and have attracted significant attention due to their intricate chemical skeletons and diverse biological activities. Some of these compounds have made substantial contributions to the human health, particularly in the treatment of the central nervous system disorders and cardiovascular conditions as well as in agricultural applications. Accordingly, their biosynthetic pathways have been extensively investigated. Current studies reveal that cytochrome P450 enzymes and flavin-dependent monooxygenases (FMOs) are the primary enzymes involved in triggering carbocation, radical or epoxidation reactions following semipinacol rearrangement during the formation of spirooxindole. In some cases, spontaneous intramolecular Diels-Alder cycloaddition also yields spirooxindole skeletons. This review presents a comprehensive overview of the discovery and structure of spirooxindole alkaloids (SOAs), together with their bioactivities and distinctive biosynthetic pathways.