A selection of grapes from Sardinia: antioxidant properties

Several studies have suggested that grape extracts possess different biological actions and may be beneficial in the prevention of many human diseases, associated with oxidative stress; however rather scarce data on the biological properties of the countless varieties of grapes growing in Sardinia are available. Grape and wine extracts are known to contain high levels of polyphenolic compounds. Polyphenols have been proposed to exert beneficial effects in a multitude of disease states, including cancer, cardiovascular diseases and neurodegenerative disorders. Many of the biological actions of polyphenols have been attributed to their antioxidant properties. In the present study we investigated the antioxidant effect of extracts from 6 varieties of grape growing in Sardinia (Cannonau, Cabernet-sauvignon, Malvasia, Vermentino, Chardonnay, Sauvignon), in simple in vitro systems, during autoxidation of linoleic acid at 37 degrees C and during cholesterol oxidation at 140 degrees C, in the absence of solvent. The cytotoxicity and the capacity of grape extracts to inhibit MDA production were evaluated in the human colon adenocarcinoma cell line, Caco-2. This cell line spontaneously undergoes full differentiation in vitro with enterocyte-like features and has been recognized as a suitable model for evaluating the effect of nutrient components. All tested grape extracts showed no cytotoxicity in the range 25-100 mu g/ml and showed a significant antioxidant activity, beeing the native grape extracts from Sardinia the most active.