Effect of select antioxidants on malondialdehyde modification of proteins.
To determine whether commonly used antioxidants alter malondialdehyde (MDA) modification of proteins, a known mechanism of free radical-related tissue injury, we studied the effect of adding 1 mg/mL of pycnogenol, 5 mM of alpha-tocopherol, 5 mM of ascorbate, and 0.2 mg/mL of an ethanol equivalent of red and white wine on MDA-protein content of endothelial cells in culture. The addition of pycnogenol but not of the other antioxidants was associated with significant reduction in MDA-protein content compared with controls (0.521 +/- 0.041 in arbritrary units versus 1.011 +/- 0.021, P < 0. 001). To determine whether the observed effect occurs distal to MDA generation, the effect of these antioxidants on the modification of bovine serum albumin with MDA generated in a cell-free system was studied. In this cell-free assay, pycnogenol but not the other antioxidants reduced MDA-BSA generation by approximately 50%. It is concluded that pycnogenol may reduce MDA modification of proteins at a step distal to MDA generation. This may be an additional mechanism of protective effects of pycnogenol against oxidative stress.
Kim
J
J
Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, Missouri 63110, USA.
Chehade
J
J
Pinnas
J L
JL
Mooradian
A D
AD
D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D002474:Cell-Free System; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D000431:Ethanol / Q000008:administration & dosage; D005419:Flavonoids / Q000008:administration & dosage; D006801:Humans; D008315:Malondialdehyde / Q000378:metabolism*; D018384:Oxidative Stress; D010936:Plant Extracts; D011506:Proteins / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D014810:Vitamin E / Q000008:administration & dosage
D000975:Antioxidants; D005419:Flavonoids; D010936:Plant Extracts; D011506:Proteins; D014810:Vitamin E; D012710:Serum Albumin, Bovine; D000431:Ethanol; D008315:Malondialdehyde; C024070:pycnogenols; D001205:Ascorbic Acid