Aristotelia chilensis, rutin and quercetin amielorates acute vascular endothelial dysfunction in rat thoracic aorta exposed to oxidative stress

The role of endothelial dysfunction (ED) and excessive oxidative stress in the development of cardiovascular diseases has recently been highlighted. The present study examined the effect of a hydro-ethanolic extract of a Chilean berry Aristotelia chilensis (folk name “maqui), and its flavonoids antioxidants rutin (RT) and quercetin (QC), on the responsivity of blood vessels exposed to oxidative stress. For functional relaxation studies, the isolated rat aortic rings (RARs) of male Wistar rats were used. To model acute oxidative stress in vitro, RARs were incubated in Krebs' solution containing either high glucose (46 mM) or the O2generator pyrogallol (50 μM). RARs exposed to either glucose or pyrogallol displayed attenuated maximum vasorelaxation responses to the endothelium-dependent vasodilator acetylcholine (Ach), and reduced nitric oxide (NO) bioavailability. These effects were fully suppressed by pre-incubation of the vessels with the maqui berry extract (MBE), RT and QC. Both, removal of the endothelium and the addition of nitric oxide synthase (NOS) inhibitor, NG-Nitro-L-Arginine Methyl Ester (L-NAME) increased the phenylephrine (Phe) response. These observation suggest that MBE, QC and RT may protect against high glucose and pyrogallol-induced endothelial dysfunction via enhanced the generation and bioavailability of NO.