Selective Inhibition of cyclooxygenase-2 by C-phycocyanin, a Biliprotein From Spirulina Platensis

Biochem Biophys Res Commun. 2000 Nov 2;277(3):599-603. doi: 10.1006/bbrc.2000.3725.

Abstract

We report data from two related assay systems (isolated enzyme assays and whole blood assays) that C-phycocyanin a biliprotein from Spirulina platensis is a selective inhibitor of cyclooxygenase-2 (COX-2) with a very low IC(50) COX-2/IC(50) COX-1 ratio (0.04). The extent of inhibition depends on the period of preincubation of phycocyanin with COX-2, but without any effect on the period of preincubation with COX-1. The IC(50) value obtained for the inhibition of COX-2 by phycocyanin is much lower (180 nM) as compared to those of celecoxib (255 nM) and rofecoxib (401 nM), the well-known selective COX-2 inhibitors. In the human whole blood assay, phycocyanin very efficiently inhibited COX-2 with an IC(50) value of 80 nM. Reduced phycocyanin and phycocyanobilin, the chromophore of phycocyanin are poor inhibitors of COX-2 without COX-2 selectivity. This suggests that apoprotein in phycocyanin plays a key role in the selective inhibition of COX-2. The present study points out that the hepatoprotective, anti-inflammatory, and anti-arthritic properties of phycocyanin reported in the literature may be due, in part, to its selective COX-2 inhibitory property, although its ability to efficiently scavenge free radicals and effectively inhibit lipid peroxidation may also be involved.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Celecoxib
  • Cyanobacteria / chemistry*
  • Cyclooxygenase 2
  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors / pharmacology*
  • Dose-Response Relationship, Drug
  • Humans
  • Insect Proteins / metabolism
  • Isoenzymes / antagonists & inhibitors*
  • Isoenzymes / metabolism
  • Lactones / pharmacology
  • Membrane Proteins
  • Microsomes / metabolism
  • Phycocyanin / pharmacology*
  • Prostaglandin-Endoperoxide Synthases / metabolism
  • Pyrazoles
  • Sheep
  • Sulfonamides / pharmacology
  • Sulfones

Substances

  • Blue biliprotein, Manduca sexta
  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors
  • Insect Proteins
  • Isoenzymes
  • Lactones
  • Membrane Proteins
  • Pyrazoles
  • Sulfonamides
  • Sulfones
  • rofecoxib
  • Phycocyanin
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • Prostaglandin-Endoperoxide Synthases
  • Celecoxib