Advances in natural coumaronochromones: a comprehensive review of natural occurrence, bioactivities, and chemical synthesis

Coumaronochromones, characterized by a distinctive benzofuro[2,3-b]chromenone core, constitute a rare subclass of isoflavonoids. Biosynthetically, they are proposed to originate from carbohydrate metabolism and the phenylpropanoid pathway like other isoflavones. To date, 92 natural coumaronochromones have been isolated and characterized from nearly 28 species across 24 genera within 7 families (including one fungal source). These compounds are predominantly distributed in the Fabaceae family, which accounts for over half (64%) of all known derivatives. Notably, approximately 20% of coumaronochromones are derived from the genus Euchresta (Fabaceae). The unique scaffold of coumaronochromones confers a broad spectrum of notable pharmacological activities, including anti-inflammatory, antibacterial, insecticidal, cytotoxic, and immunomodulatory effects, highlighting their potential as valuable natural leads for pharmaceutical and agrochemical development. This review comprehensively summarizes recent advances in the chemistry and biology of coumaronochromones, providing a detailed account of their natural occurrence, documented biological activities, and chemical syntheses.