Biological importance of structurally diversified chromenes

Compounds incorporating the chromene scaffold are largely present in natural products and display a wide variety of biological activities. Their low toxicity combined to the broad pharmacological properties have inspired medicinal chemists in the search for new therapeutic agents. This review covers the literature between 1993 and on the biological activity of 2H- and 4H-chromenes, both from natural and synthetic origin. Includes a section that identifies a selection of chromene-based natural products, followed by recent literature on bioactive natural chromenes and the corresponding source, covering plants and fruits. Synthetic chromenes are equally important and a separate section addresses the use of these derivatives as new leads for drug discovery. Different biological targets were identified, namely those associated with anticancer, antimicrobial, anti-inflammatory, antithrombotic and antipsychotic activities.We acknowledge the financial support from University of Minho, FCT through the Portuguese NMR network (RNRMN), Project F-COMP-01-0124-FEDER-022716 (ref. FCT PEst-C/QUI/UI0686/2011) FEDER-COMPETE and for the postdoctoral grant awarded to Marta Costa (SFRH/BPD/79609/2011).