Naturally Occurring Chromene Containing Molecules and their Isolation Protocols

Natural products have been used as major sources of therapeutic agents in drug discovery since the ancient eras. Natural products have been widely studied in the physical and biological sciences, including nutrition, health, bio-medical, and other interrelated sciences. Because of their unique chemical diversity and bioactivity, they have continued to offer templates for the development of novel forms of drugs. In the field of traditional medicine, natural products have been used for a very long time in the form of decoctions, medicinal extracts, infusions, or other therapeutic preparations. Chromene is one of the essential chemical constituents, derived from the conversion of multiple biosynthetic pathways present in the plant as well as animal kingdoms, which represents a remarkable group of structurally varied secondary metabolites. The scaffold is considered an important class of oxygenated heterocyclic compounds as two forms of 2H/4H-chromene (2H/4H-Ch) with versatile biological profiles. Chromenes are the basic backbone of various polyphenols, alkaloids, tocopherols, anthocyanins, etc. Crotin, Crotaramine, Dysoline, Malachromone, Oxalicumones A-C, Khellin, Baicalin, Diosmin, etc. are some examples of naturally isolated chromene fused compounds that are reported for the treatment of diverse health ailments. Their unique structure and varied pharmacological activities may provide new leads for the discovery of drugs with their action. In recent years, the need to develop effective and selective methods for the extraction and isolation of new natural products has been increasingly felt. This chapter presents the extraction, isolation, and characterization processes of the chromenes by the natural sources, illumination of the structures of purified chromenes, and their bioactivity.