Inhibition of COX Isoforms by Nutraceuticals

Abstract

Humans have two isoforms of Prostaglandin H Synthase or cyclooxygenase: COX-1 and COX-2. COX-1 is cytoprotective. COX-2 inhibitors reduce inflammation without the risk of ulceration and kidney damage. The ideal nutraceutical would inhibit COX-2 synthesis while preserving COX-1 synthesis. The hypothesis for this research was that COX inhibitors would fall primarily into three categories: COX-2 specific inhibition, non-specific inhibition (COX-1 and COX-2), and minimal inhibition. The human Cayman COX inhibitor screening assay was used to determine the inhibitory concentration 50 (IC50) of COX-1/ COX-2 activity of each nutraceutical. The assay was run, in duplicate, with three concentrations of a suspected inhibitor, a standard curve of eight concentrations, a non-specific binding sample, and a maximum binding sample. The inhibition and concentration of each sample was then put on a multiple regression best-fit line and the IC50 determined. For comparison, ibuprofen, rofecoxib, naproxen, and indomethacin were used. Positive results were seen for ipriflavone, resveratrol, MSV-60, amentoflavone, ruscus extract and notoginseng. Glucosamine, nexrutine, and berberine did not inhibit either isoform.