Several literature reports had highlighted the significance of coumarin nucleus as a source of potential candidates for anti-inflammatory drug development.

Curcumin, a prominent constituent of the rhizome of Curcuma longa L., possesses versatile biological properties, which is evidenced from the extensive research during the last half century. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has potential against various malignant diseases, such as allergies, arthritis, Alzheimer's disease, and other chronic illnesses. In the last decade it has been much explored and various synthetic analogues have been prepared and evaluated for various pharmacological activities that render it as a lead molecule against several biological targets. To accelerate this lead molecule from kitchen to clinic, around 65 clinical trials are underway worldwide to assess its therapeutic potential. Thus, there is continued interest in the synthesis of new curcumin analogues with a similar safety profile, but increased activity and improved oral bioavailability. The present review article describes recent developments in curcumin chemistry with emphasis on the semi-synthesis, synthesis pharmacological properties and SAR of various curcumin analogues reported from 1994 to mid 2013.

Non-steroidal anti-inflammatory drugs (NSAIDs) are of huge therapeutic benefit in the treatment of rheumatoid arthritis and various types of inflammatory conditions. The target for these drugs is cyclooxygenase (COX), a rate-limiting enzyme involved in the conversion of arachidonic acid into inflammatory prostaglandins. COX-2 selective inhibitors are believed to have the same anti-inflammatory, anti-pyretic and analgesic activities as that of nonselective inhibitor NSAIDs with little or none of the gastrointestinal side effects. Thus, in the last 6-7 years several selective COX-2 inhibitors including coxibs were discovered and introduced into clinic. Recent reports evidence that selective COX-2 inhibitor such as rofecoxib, can lead to thrombotic cardiovascular events through inhibition of prostacyclin formation in the infracted heart. This has resulted in withdrawal of rofecoxib from the clinic in September 2004. Moreover, the COX-2/COX-1 selectivity ratio is vital in the design of COX-2 inhibitory drugs, as it is clear from rofecoxib, which is more than 50-fold COX-2 selective. After looking at all above mentioned facts, natural product-based compounds seem better as these compounds are generally supposed to be devoid of severe side effects. The literature indicates that natural product-based compounds are mainly COX-1 selective. Through minor semisynthetic changes in the structures, their selectivity towards COX-2 can be increased. The present review article addresses natural product COX inhibitors of plant and marine origin, reported during last ten years and their advantages, possible leads for further development and current status. In addition we describe our experience in the characterization, design and synthesis of potential natural COX inhibitors.