Characterization of the Effects of Two Polyphenols-Rich Plant Extracts on Isolated Diabetic Human Mammary Arteries

The beneficial effects of fiavonoids on endothelial function in pathological conditions associated with oxidative stress, such as diabetes mellitus, represents an important research direction. The aim of the present study was to assess the vasodilator response of human internal mammary arteries (IMA) fragments isolated from diabetic patients undergoing coronary artery by-pass grafting, to different concentrations of two plant extracts obtained from hawthorn and green tea, rich in polyphenols. Arterial segments were harvested from 10 male patients with type 2 diabetes and ischemic heart disease and studied in organ bath in the presence vs. absence of plant extracts. We obtained a significant decrease in contractility and a dose-dependent improvement of relaxation after pre-treatment with extracts. We can conclude that hawthorn and green tea extracts significantly improved the endothelium-dependent relaxation in diabetic vessels, suggesting that polyphenols may improve endothelial function via the increase in nitric oxide bioavailability in a disease associated with significant cardiovascular impairment.