A Synthetic Approach Towards The Development of Novel Coumarin Analogs As Potential Pharmaceutical Agents

Abstract

Coumarins, also known as benzopyrones, have been identified from natural sources, especially green plants. The simplest member of this class is coumarin (1) (anhydride of ocoumaric acid),1 is a white crystalline lactone. The study of coumarins began more than 200 years ago. The name of this chemical family is derived from Coumarouna odorata Aube (Dipteryx odorata), from which it was isolated, for the first time. The coumarin nucleus corresponds to benzo-α-pyrone (2H-1-benzopyran-2-one) whose systematic nomenclature was established by IUPAC.2 Coumarins comprise a group of natural compounds found in a variety of plant sources. The very long association of plant coumarins with various animal species and other organisms throughout evolution may account for the extraordinary range of biochemical and pharmacological activities of these chemicals in mammalian and other biological systems. Coumarins have important effects in plant biochemistry and physiology, acting as antioxidants, enzyme inhibitors and precursors of toxic substances. In addition, these compounds are involved in the action of plant growth hormones and growth regulators, the control of respiration, photosynthesis, as well as defense against infection. The coumarins have long been recognized to possess anti-inflammatory, antiallergic, hepatoprotective, antithrombotic, antiviral, and anticancer activities. In addition, coumarins are known to be lipid lowering agents with moderate triglyceride lowering activity. Furthermore, hydroxycoumarins are powerful chain-breaking antioxidants and can prevent free radical injury by scavenging reactive oxygen species. Over and above the discoveries made by isolation of coumarins from the hundreds of species of plants and other organisms, and the derivatives of synthetic origin significantly increases the number of coumarin structures known till today. 1.2. Classification of coumarins Coumarins have been genarally categorised as follows: a. Simple coumarins b. Furanocoumarins c. Pyranocoumarins d. Biscoumarins and Triscoumarins e. Coumarinolignans.