Procyanidins extracted from pine bark protect α‐tocopherol in ECV 304 endothelial cells challenged by activated RAW 264.7 macrophages: role of nitric oxide and peroxynitrite

Abstract

A co-culture system was used to study the effect of reactive nitrogen species (RNS) generated by RAW 264.7 macrophages grown on filters and activated by lipopolysaccharide and interferon-γ, on the α-tocopherol levels in ECV 302 endothelial cells. The results indicate that: RNS generated by activated macrophages or by direct administration of peroxynitrite lead to a significant loss of α-tocopherol in endothelial cells; pre-incubation with procyanidin extracted from pine bark (Pycnogenol) protects α-tocopherol of endothelial cells and enhances by about 15% basal endogenous levels of α-tocopherol. These results demonstrate flavonoids participate in the cellular antioxidant network and suggest that Pycnogenol may play an important role in the protection of endothelium from oxidative stress induced by reactive nitrogen species.