Systematic review of natural coumarins in plants (2019-2024): Chemical structures and pharmacological activities

Coumarins constitute one of the most substantial classes of secondary metabolites, characterised by a fundamental α-benzopyranone skeleton, which serves as an overarching nomenclature for o-hydroxycinnamyl lactone moieties. These chemical constituents are widely distributed in various plant species. Based on the nature and loci of their substituents, these compounds can be further classified into simple coumarins, furanocoumarins, pyranocoumarins, isocoumarins, biscoumarins and other coumarins. Contemporary pharmacological research has revealed that coumarins exhibit a spectrum of properties, including antibacterial, antioxidant, anticancer, anti-inflammatory and hypoglycaemic activities. Owing to their diverse of structures and pharmacological actions, coumarins are widely used in cuisine, cosmetics and pharmaceutical industries. An extensive body of scholarly literature has been produced in this domain, although a notable paucity in the compilation and updating of references has been identified since 2019. Herein, the chemical structures and pharmacological activities of coumarins reported for the first time between 2019 and 2024 were systematically summarised. In total, 220 scholarly articles involving 574 coumarins reported for the first time in plants were included in this review. In addition, the biosynthetic pathways of some common types of coumarins (simple coumarins, furanocoumarins, and pyranocoumarins) are also preliminarily summarised in this paper. Meticulously analyzing and synthesising the published literature will lay a solid foundation for further investigation and extensive utilisation of coumarin derivatives.