Grape is qualitatively and quantitatively very rich in polyphenols. In particular, anthocyanins, flavonols and stilbene derivatives play very important roles in plant metabolism, thanks to their peculiar characteristics. Anthocyanins are responsible for the color of red grapes and wines and confer organoleptic characteristics on the wine. They are used for chemotaxonomic studies and to evaluate the polyphenolic ripening stage of grape. They are natural colorants, have antioxidant, antimicrobial and anticarcinogenic activity, exert protective effects on the human cardiovascular system, and are used in the food and pharmaceutical industries. Stilbenes are vine phytoalexins present in grape berries and associated with the beneficial effects of drinking wine. The principal stilbene, resveratrol, is characterized by anticancer, antioxidant, anti-inflammatory and cardioprotective activity. Resveratrol dimers and oligomers also occur in grape, and are synthetized by the vine as active defenses against exogenous attack, or produced by extracellular enzymes released from pathogens in an attempt to eliminate undesirable toxic compounds. Flavonols are a ubiquitous class of flavonoids with photo-protection and copigmentation (together with anthocyanins) functions. The lack of expression of the enzyme flavonoid 3',5'-hydroxylase in white grapes restricts the presence of these compounds to quercetin, kaempferol and isorhamnetin derivatives, whereas red grapes usually also contain myricetin, laricitrin and syringetin derivatives. In the last ten years, the technological development of analytical instrumentation, particularly mass spectrometry, has led to great improvements and further knowledge of the chemistry of these compounds. In this review, the biosynthesis and biological role of these grape polyphenols are briefly introduced, together with the latest knowledge of their chemistry.

In the coming years, European death rates because of cancer will further decline, but the overall number of cases will increase, mostly as a consequence of the ageing of the population. The target for cancer prevention in Europe will remain a healthy diet and control of obesity in addition to a decrease in smoking. A healthy diet model in European countries is the traditional Mediterranean diet, which is based on abundant and variable plant foods, high consumption of cereals, olive oil as the main (added) fat, low intake of (red) meat and moderate consumption of wine. The Mediterranean diet is associated with a reduced risk of cardiovascular disease and cancer. The biological mechanisms for cancer prevention associated with the Mediterranean diet have been related to the favourable effect of a balanced ratio of omega 6 and omega 3 essential fatty acids and high amounts of fibre, antioxidants and polyphenols found in fruit, vegetables, olive oil and wine. The Mediterranean diet also involves a ‘Mediterranean way of drinking’, that is, regular, moderate consumption of wine mainly with food. This pattern of drinking increases longevity, reduces the risk of cardiovascular disease and does not appreciably influence the overall risk of cancer. However, heavy alcohol drinking is associated with digestive, upper respiratory tract, liver and breast cancers; therefore, avoidance or restriction of alcohol consumption to two drinks/day in men and one drink/day in women is a global public health priority.

Although it is clearly established that the abuse of alcohol is seriously harmful to health, much epidemiological and clinical evidence seem to underline the protective role of moderate quantities of alcohol and in particular of wine on health. This narrative review aims to re-evaluate the relationship between the type and dose of alcoholic drink and reduced or increased risk of various diseases, in the light of the most current scientific evidence. In particular, in vitro studies on the modulation of biochemical pathways and gene expression of wine bioactive components were evaluated. Twenty-four studies were selected after PubMed, Scopus and Google Scholar searches for the evaluation of moderate alcohol/wine consumption and health effects: eight studies concerned cardiovascular diseases, three concerned type 2 diabetes, four concerned neurodegenerative diseases, five concerned cancer and four were related to longevity. A brief discussion on viticultural and enological practices potentially affecting the content of bioactive components in wine is included. The analysis clearly indicates that wine differs from other alcoholic beverages and its moderate consumption not only does not increase the risk of chronic degenerative diseases but is also associated with health benefits particularly when included in a Mediterranean diet model. Obviously, every effort must be made to promote behavioral education to prevent abuse, especially among young people.

Several studies have shown that fresh grape and its derivatives contain phenolic compounds exhibiting antioxidant and health promoting effects, particularly in relation to the cardiovascular system. In this study, two methods were developed to characterize sixteen varieties of table and wine grapes: (1) a LC-MS method to identify major and minor phenolic compounds; and (2) a HPLC-DAD method to quantify the most representative compounds. Sixty-seven molecules belonging to different classes of phenolic compounds were identified: anthocyanins, flavan-3-ols, flavonols, stilbenes and organic acids. In parallel, the free radical scavenging activity and anti-inflammatory activities of the 16 grape varieties were evaluated. The results showed a good correlation between the total phenolic content and the biological activity. Extracts from Exalta and Albarossa grape varieties were the most active in reducing IL-8 release by gastric epithelial cells (IC₅₀ = 8.48 μg mL⁻¹ and 6.68 μg mL⁻¹, respectively), a biomarker of inflammatory processes. The observed biological activities were mainly associated with skin and seed extracts/portions. The interest in studying table grapes and their non-fermented derivatives as sources of healthy compounds has increased in the last few years and our findings suggest that table grapes and their fresh derivatives, in addition to wine, could be involved in the health promoting effects of the Mediterranean diet.