Cardioprotective effects of a proanthocyanidin-rich fraction from Croton celtidifolius Baill: focus on atherosclerosis.

Proanthocyanidins are the most abundant polyphenols in human diets. Epidemiological studies have pointed to proanthocyanidins as promising molecules that could prevent the development of several coronary syndromes by inhibiting the atherogenic process. The present study was designed to investigate the antiatherogenic effects of a proanthocyanidin-rich fraction (PRF) obtained from Croton celtidifolius Baill (Euphorbiaceae) barks. In isolated human LDL, PRF caused a concentration-dependent inhibition of Cu2+-induced oxidative modifications, evidenced by the increasing of the lag phase of lipid peroxidation and decreasing in the oxidation rate (Vmax), moreover, the protein moieties from LDL were protected against Cu2+-induced oxidation. In human umbilical vein endothelial cells (HUVECs), PRF reduced the ROS production stimulated by oxidized LDL. Herein, we demonstrate that oral treatment with PRF improved endothelium-dependent vasorelaxation in hypercholesterolemic LDL receptor knockout mice (LDLr-/-), however, the fraction did not modify plasma lipids and atherosclerotic lesion size in this experimental model. Finally, our results showed for the first time that PRF prevent isolated LDL oxidation, decrease oxidative stress in endothelial cells and improve endothelial function in mice.

Diphenyl diselenide effectively reduces atherosclerotic lesions in LDLr -/- mice by attenuation of oxidative stress and inflammation.

Glutathione peroxidase (GPx) plays an important role in the antioxidant defense of the vascular wall, and its deficiency has been implicated in the development of atherosclerotic lesions. This study analyzed the potential of diphenyl diselenide (DD), a simple organoselenium compound with GPx-like activity, to reduce atherosclerosis. Herein, we demonstrate that oral treatment with low doses of DD potently reduced the formation of atherosclerotic lesion in hypercholesterolemic low-density lipoprotein (LDL) receptor knockout (LDLr -/-) mice. This reduction was accompanied by significantly improved endothelium-dependent vasorelaxation, lower nitrotyrosine and malondialdehyde levels, decrease in vessel-wall infiltration by inflammatory cells, and prevention of upregulation of the proatherogenic monocyte chemoattractant protein-1. Studies in J774 macrophage-like cells show that DD significantly decreased oxLDL-induced formation of foam cells and the generation of reactive oxygen species and inflammatory mediators. Our results reveal the antiatherogenic actions of DD by modulating intracellular signaling pathways related to antioxidant and anti-inflammatory responses.