Pycnogenol protects vascular endothelial cells from t-butyl hydroperoxide induced oxidant injury

The active oxygen induced and free radical mediated oxidation of biological molecules, membranes, and tissues has been suggested as a major cause of cancer, atherosclerosis, and aging. Damage of endothelial cells may lead to cardiovascular and cerebrovascular diseases. In the present study, the antioxidant effect of pycnogenol (procyanidins extracted from Pinus maritima) was investigated in vitro using vascular endothelial cells. Confluent monolayers of bovine pulmonary artery endothelial cells (PAEC) were preincubated with different concentrations of pycnogenol for 16 h, washed, and then exposed to an organic oxidant t-butyl hydroperoxide (tBHP) for 3 or 4 h. Cellular injury was assessed by measuring cell viability with methylthiazol tetrazolium (MTT) assay and by determining the release of intracellular lactate dehydrogenase (LDH). Lipid peroxidation products of PAEC were monitored as malondialdehyde (MDA) with a thiobarbituric acid fluorometric assay. Incubation of tBHP (75, 100, or 125 microM) with PAEC decreased cell viability, increased LDH release, and elevated MDH production. Preincubation of PAEC with pycnogenol (10-80 micrograms/mL) before tBHP exposure significantly increased cell viability, decreased LDH release, and reduced MDA production. These results demonstrate that pycnogenol can protect vascular endothelial cells from oxidant injury. The data thus suggest that pycnogenol may be useful for the prevention of disorders associated with oxidative damage.