Olive & Oil 31/08/2015

How much health benefits for quality extra virgin olive oil

Phenolic content of extra virgin olive oil is essential to restore endothelial dysfunction. Olive oil compounds affect endothelial cell functions essential for angiogenesis. Hydroxytyrosol is useful against oxidative alterations induced by mercury in human erythrocytes

Extra Virgin Olive Oil (EVOO) contains monounsaturated fatty acids and multiple minor components with biological properties and health benefits. We evaluate whether a diet supplemented on Oleaster®(OT), an EVOO obtained by a new process aimed to increase phenolic composition, provided additional benefits to those observed in the animals fed a diet rich in traditional EVOO on atherosclerosis development and vasomotor function in aortic vessel of ApoE−/− mice. Results were compared with those obtained in mice fed an EVOO, a standard diet (SD) or a high fat diet (HFD) rich in saturated fatty acids. Both extra-virgin olive oils reduced macrophage accumulation and protein expression of iNOS, ICAM-1 and VCAM-1, TNF-α and NF-κB, independently of its phenolic content toward values found in SD. Superoxide anion production was also reduced to the same extent in Apo E−/− mice fed EVOO or OT. Endothelial function assessed by ACh-induced vasodilatation, and lipid accumulation within the atherosclerotic plaque were restored in OT- but not in EVOO-fed mice. We conclude that EVOO contribute to prevent the inflammatory markers of atherosclerosis plaque progression but the polyphenolic content is not responsible for this effect. However, those compounds are able to restore endothelial function and to reduce lipid accumulation within the atherosclerotic lesion.

Vascular endothelial growth factor (VEGF) triggers crucial signaling processes that regulate tumor angiogenesis and, therefore, represents an attractive target for the development of novel anticancer therapeutics. Several epidemiological studies have confirmed that abundant consumption of foods from plant origin is associated with reduced risk of developing cancers. In the Mediterranean basin, the consumption of extra virgin olive oil is an important constituent of the diet. Compared to other vegetable oils, the presence of several phenolic antioxidants in olive oil is believed to prevent the occurrence of a variety of pathological processes, such as cancer. While the strong antioxidant potential of these molecules is well characterized, their antiangiogenic activities remain unknown. The aim of this study is to investigate whether tyrosol (Tyr), hydroxytyrosol (HT), taxifolin (Tax), oleuropein (OL) and oleic acid (OA), five compounds contained in extra virgin olive oil, can affect in vitro angiogenesis. We found that HT, Tax and OA were the most potent angiogenesis inhibitors through their inhibitory effect on specific autophosphorylation sites of VEGFR-2 (Tyr951, Tyr1059, Tyr1175 and Tyr1214) leading to the inhibition of endothelial cell (EC) signaling. Inhibition of VEGFR-2 by these olive oil compounds significantly reduced VEGF-induced EC proliferation and migration as well as their morphogenic differentiation into capillary-like tubular structures in Matrigel. Our study demonstrates that HT, Tax and OA are novel and potent inhibitors of the VEGFR-2 signaling pathway. These findings emphasize the chemopreventive properties of olive oil and highlight the importance of nutrition in cancer prevention.

Hydroxytyrosol (HT) is a phenolic antioxidant naturally occurring in virgin olive oil. In this study, we investigated the possible protective effects of HT on the oxidative and morphological alterations induced by mercury (Hg) in intact human erythrocytes. These cells preferentially accumulate this toxic heavy metal. More importantly, Hg-induced echinocyte formation correlates with increased coagulability of these cells. Our results indicate that HT treatment (10–50 µM) prevents the increase in hemolysis and Reactive Oxygen Species (ROS) generation induced by exposure of cells to micromolar HgCl2 concentrations as well as the decrease in GSH intracellular levels. Moreover, as indicated by scanning electron microscopy, the morphological alterations are also significantly reduced by HT co-treatment. Taken together our data provide the first experimental evidence that HT has the potential to counteract mercury toxicity. The reported effect may be regarded as an additional mechanism underlying the beneficial cardio-protective effects of this dietary antioxidant, also endowed with significant anti-atherogenic and anti-inflammatory properties.

di R. T.