Mp Melis

Protective effect of hydroxytyrosol and tyrosol against oxidative stress in kidney cells.

Bioavailability studies in animals and humans fed with extravirgin olive oil demonstrated that hydroxytyrosol and tyrosol, the major simple phenolic compounds in extravirgin olive oil, are dose-dependently absorbed and excreted. Once absorbed, they undergo extensive metabolism; hydroxytyrosol and tyrosol concentrate mainly in the kidney, where they may exert an important role in the prevention of oxidative stress induced renal dysfunction. In this study we monitored the ability of hydroxytyrosol and tyrosol to protect renal cells (LLC-PK1) following oxidative damage induced by H2O2. Oxidative stress was evaluated by monitoring the changes of the membrane lipid fraction. Hydroxytyrosol exerted a significant antioxidant action, inhibiting the production of MDA, fatty acids hydroperoxides and 7-ketocholesterol, major oxidation products of unsaturated fatty acids and cholesterol, and thus protecting the cells from H2O2-induced damage. Tyrosol, instead, in this experimental model, did not exert any protective effect.

The effect of clarifying substances on organophosphorous insecticide residues in wine

Abstract The influence of six clarifying agents (bentonite, charcoal, potassium caseinate, gelatine, polyvinylpolypyrrolidone and colloidal silicon dioxide) on pesticide residues in wine was studied. Thirteen pesticides belonging to the class of organophosphorous insecticides were studied at two different doses. Almost all clarifying agents showed no or limited ability in reducing pesticide residues. The only exception was charcoal which allowed complete or almost complete elimination of pesticide residues, especially when they were at lower doses. Charcoal activity usually decreased on increasing pesticide water solubility. Therefore, pesticides that are highly soluble in water, such as dichlorvos and dimethoate, showed no sensible decrease.

Antioxidant properties of the phenolic fraction of Sardinian wines

The aim of this study was to compare the antioxidant capacities of the phenolic fraction of wines from Vitis vinifera grapes cultivated in Sardinia (three native: Cannonau, Malvasia, Vermentino and three non-native types: Cabernet-sauvignon, Chardonnay and Sauvignon), in simple in vitro systems. All the extracts showed a significant antioxidant activity, beeing the native wine extracts the most active in inhibiting the lipid peroxidation process.