Other Natural Cyclooxygenase Inhibitors

The deepened understanding of the mode of action of Aspirin vfas an important prerequisite that in the following years a number of other natural products were discovered, which, like saUcyhc acid from willow bark (Cortex salix alba), exhibit analgesic and anti-inflammatory activity. 

Fan Zhang at Cornell University in New York and Ajay Goel at the University of California in San Diego found that curcumin, the yellow dye in turmeric (Curcuma longa), inhihits in a concentration- and time-dependent manner the expression of cyclooxygenase-2 and the formation of prostaglandin E2 (PGE2) (Fig. 5.79 and Fig. 5.80). [165,166] 

A similar effect is now as well ascribed to resveratrol, aphytoalexin from the skin of black grapes, and to the Japanese knotweed (Polygonum cuspidatum). The active compound, widely used in traditional Chinese herhal medicine, prevents the increased expression of human cyclooxygenase-2 and hence a higher COX-2 activity. 

Extracts from Wilford s three-wing fruit (Thunder God Vine, Tripterygium wilfordii) have likewise been used in traditional Chinese medicine since ancient times for the treatment of rheumatoid arthritis. The pharmacologically important component of the extract proves to be triptohde, which inhihits the lipo-polysaccharide-induced COX-2 expression and the release of PGE2, and has thereby an anti-inflammatory effect. [167,168] It is remarkable that the extract does not affect the COX-1 activity. 

Lastly omega-3 fatty acids, which are physiologically valuable nutritional components of various vegetable and fish oils, are attributed to the selective inhibition of COX-2 mRNA, without impairing COX-1 expression. [169,170] 

---