Effect of Chlorophyll-Related Compounds on the Hemolysis of Erythrocytes

Abstract

Some of the decomposition products of chlorophylls are known to cause photosensitivity in animals and photooxidation of foods.To evaluate the cell damage arising from prooxidant activities of chlorophyll-related compounds [chlorophylls (CHL) a and b, pheophytins (PHY) a and b, pyropheophytin (PYROPHY) a, pheophorbide (PHEO) a and pyropheophorbide (PYRO) a], we have studied the effect of each compound on hemolysis of erythrocytes under light irradiation. PYRO-a caused the strongest hemolysis, followed by PHEO-a. Pheophytins were stronger than chlorophylls and, especially, PHY-b caused higher hemolysis than PHY-a and PYROPHY-a. The 50% hemolysis doses of PYRO-a, PHEO-a, PHY-a and PHY-b with rabbit erythrocytes were 0.0005, 0.0012, 0.0156 and 0.0092μmol/ml, respectively. The hemolysis activities of chlorophylls were very weak, and a high dose (0.02μmol/ml) caused less than 20% hemolysis.The decomposition of chlorophyll-related compounds by erythrocytes was examined. PHY-b was decomposed most effectively; the residual amount (%) after a 5hr irradiation was 11%, and pheophorbide b was detected in the erythrocyte suspension. Similarly, PHEO-a and PYRO-a were detected after addition of PHY-a and PYROPHY-a to erythrocytes, respectively.