Polyphenol fraction of extra virgin olive oil protects against endothelial dysfunction induced by high glucose and free fatty acids through modulation of nitric oxide and endothelin-1.

Epidemiological and clinical studies have reported that olive oil reduces the incidence of cardiovascular disease. However, the mechanisms involved in this beneficial effect have not been delineated. The endothelium plays an important role in blood pressure regulation through the release of potent vasodilator and vasoconstrictor agents such as nitric oxide (NO) and endothelin-1 (ET-1), respectively, events that are disrupted in type 2 diabetes. Extra virgin olive oil contains polyphenols, compounds that exert a biological action on endothelial function. This study analyzes the effects of olive oil polyphenols on endothelial dysfunction using an in vitro model that simulates the conditions of type 2 diabetes. Our findings show that high glucose and linoleic and oleic acids decrease endothelial NO synthase phosphorylation, and consequently intracellular NO levels, and increase ET-1 synthesis by ECV304 cells. These effects may be related to the stimulation of reactive oxygen species production in these experimental conditions. Hydroxytyrosol and the polyphenol extract from extra virgin olive oil partially reversed the above events. Moreover, we observed that high glucose and free fatty acids reduced NO and increased ET-1 levels induced by acetylcholine through the modulation of intracellular calcium concentrations and endothelial NO synthase phosphorylation, events also reverted by hydroxytyrosol and polyphenol extract. Thus, our results suggest a protective effect of olive oil polyphenols on endothelial dysfunction induced by hyperglycemia and free fatty acids.

In vitro study of the cytotoxicity and antiproliferative effects of surfactants produced by Sphingobacterium detergens.

The application of biosurfactants in the biomedical field is growing due to their antimicrobial activity, low cytotoxicity and ability to induce apoptosis in cancer cells. In the light of this therapeutic potential, as well as possible applications in cosmetics or as drug vehicles in pharmaceutical products, a new biosurfactant produced by Sphingobacterium detergens was investigated for its haemolytic activity and cytotoxic and antiproliferative effects in different cell lines. Fraction A showed 100% haemolysis in rabbit erythrocytes, but in Fraction B the rate was only 83%. When comparing cytotoxicity values (IC50) of the two fractions in model fibroblast and keratinocyte cell cultures, Fraction B was less cytotoxic, showing lower values than the reference compound SDS, indicating low skin irritability. Finally, in non-differentiated intestinal Caco-2 cultures, Fractions A and B reduced cell proliferation and induced apoptosis by 44% and 75%, respectively. According to these results, biosurfactants produced by S. detergens have potential application in cosmetic and pharmaceutical formulations.

Resveratrol metabolites have an antiproliferative effect on intestinal epithelial cancer cells.

Trans-resveratrol (RV) is an active polyphenol with numerous physiological properties including antitumour activity, especially in colon cancer. RV is metabolized in the intestine and then in the liver to sulphated and glucuronidated forms that are exported to target organs. After exerting their effects, they are eliminated in the urine and stools. There are few and contradictory findings on the biological effects of RV metabolites. On the basis of RV metabolism, we selected three metabolites RV 3-O-sulphate, RV 3-O-glucuronide and RV 4'-O-glucuronide, and studied their effects on cell growth inhibition, the cell cycle and apoptosis using human adenocarcinoma cell line (Caco-2 cell) cultures. Our results show that RV metabolites have an antioxidant activity similar to that RV. Moreover, all metabolites inhibited cell growth in a concentration-dependent manner as well as [(3)H] thymidine incorporation. Furthermore, we observed an increase in the percentage of cell in G0/G1 phase induced by RV metabolite treatments, as well as the induction of apoptosis. On the basis of our results we propose, for the first time, that RV metabolites remain active after their biosynthesis, contributing to the health benefits attributed previously only to RV. These metabolites are a potential target for more research into the prevention and treatment of colon cancer.