Cyclooxygenase COX is an enzyme responsible for formation of important biological mediators called prostanoids. Some of the prostanoids include prostaglandins, prostacyclin and thromboxane.
   Cyclooxygenase inhibitors can reduce symptoms of inflammation and pain. Aspirin and ibuprofen (Motrin) work as cyclooxygenase inhibitors. There are a number of natural herbs that are being discovered to have cyclooxygenase inhibiting activity. I will update this site as more information becomes available on these natural herbs or herbal extracts.

Two types
COX-1 and COX-2 are two cyclooxygenase enzymes responsible for prostanoid production. COX-2 is expressed in inflammatory cells and fibroblasts of the gastric (stomach) mucosa, and through the production of various growth factors including hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), plays a key role in the repair process of tissues.

Herbs and supplements
There are many herbs and dietary supplements that have an effect on COX enzymes, with time I will add more to the list.

Ashwagandha as cyclooxygenase 2 inhibitor
Ashwagandhanolide, a Bioactive Dimeric Thiowithanolide Isolated from the Roots of withania somnifera.
Journal of natural products. 2006, Jawahar Autonagar, Vijayawada, India, and Bioactive Natural Products and Phytoceuticals, Department of Horticulture and National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan.
A new dimeric withanolide, ashwagandhanolide, inhibited lipid peroxidation and the activity of the enzyme cyclooxygenase-2 in vitro.

Fish oil, omega 3 oils
Skepticism about the health benefits of fish oil is largely the result of the incomplete understanding of the biochemistry of omega3 essential fatty acids. Recent work has confirmed the roles of omega3 fatty acids in gene transcription and signal transduction, and has given insight into the effects of eicosapentaenoic acid (EPA) and the EPA / arachidonic acid (AA) ratio on prostanoid (PG) metabolism and function. One pronounced effect of fish-oil-induced increases in EPA / AA ratios is decreased prostaglandin formation from AA via cyclooxygenase-1, because EPA inhibits this isoform. In addition, cells lacking endogenous alkyl-peroxide-generating systems and thus having a low 'peroxide tone' cannot oxygenate EPA via cyclooxygenase-1. Platelets, however, which are equipped with a lipoxygenase that can produce an abundance of hydroperoxide from AA, can form small amounts of thromboxane A3 from EPA via cyclooxygenase -1. A second major consequence of elevated EPA / AA ratios is significantly increased production of 3-series PGs, including PGE3, via cyclooxygenase-2.

Ginger herb
Cyclooxygenase-2 inhibitors in ginger.
Fitoterapia. 2010.
Ginger roots have been used to treat inflammation and have been reported to inhibit cyclooxygenase (COX). Purified 10-gingerol, 8-shogaol and 10-shogaol inhibited COX-2. No inhibition of COX-1 was detected.

Risks
Am J Clin Nutr. December 2013. Clinical use of cyclooxygenase inhibitors impairs vitamin B-6 metabolism. Long-term celecoxib and naproxen use reduced hepatic pyridoxal-5'-phosphate in mice. Nonselective cyclooxygenase inhibitor naproxen significantly decreased vitamin B-6 vitamers in the kidney.