Comparative antioxidant activity of cultivated and wild Vaccinium species investigated by EPR, human neutrophil burst and COMET assay.

OBJECTIVES: The Vaccinium (V.) spp. berries are considered a source of antioxidants, mainly belonging to polyphenols, specifically flavonoids and anthocyanins. Wild genotypes generally contain more antioxidants than cultivated counterparts. So, seven different antioxidants assays on extracts from cultivated and wild Vaccinium berries were performed, to evaluate their difference in terms of bioactivity on oxidative protection and minimum dosage to have a significant action. MATERIALS AND METHODS: Four cell-free antioxidant assays (ABTS radical scavenging and electronic paramagnetic resonance using Fremy's salt, superoxide anion and hydroxyl radical), and three assays on human cells (two luminol amplified chemiluminescence, LACL, one on DNA damage, COMET) were used to measure the effects of cultivated blueberry (V. corymbosum) and wild bilberry (V. myrtillus) on the differently induced oxidative stress. Concentrations vs activity patterns were obtained by successive dilutions of extracts in order to identify both EC50 and minimum significant activity (MSA). RESULTS: All the assays (except for the hydroxyl radical scavenging) showed a good relationship mainly with anthocyanin and polyphenol content and the significant greater activity of wild Vaccinium extracts. In fact, LACL data gave an EC50 of 11.8 and an MSA of 5.2 g were calculated as fresh weight dosage in cultivated berries, compared with lower doses in wild berries, EC50 of 5.7 g and MSA of 3.4 g. CONCLUSIONS: Wild Vaccinium extracts averaged 3.04 and 2.40 fold more activity than cultivated extracts by EC50 and MSA, respectively. COMET assay confirmed the stronger action on DNA protection in wild samples.

Effects of different fungicide treatments on grape, must and wine quality.

The aim of this study was to evaluate the effectiveness of natural products and low-rate copper formulations against grapevine downy mildew, in order to reduce or replace copper use in organic farming, and to assess the effects on the qualitative parameters of grape, must and wine of the different treatments. The trial was carried out in an organic vineyard in accordance with the EPPO/OEPP guidelines. Plots were prepared, each containing 12 vine-plants and repeated four times in randomized blocks. At harvest, representative grape samples were picked off from the plots treated with the different products: for each treatment, a random sub-sample was kept for analyses, the remaining part was processed to produce wine. Grapes, musts and wines were characterized for their food quality indices, as well as for their nutraceutical profiles and antioxidant activity. On must and wine, sugars, acidity and pH were determined according to official methods. On grape and wine, total polyphenol, flavonoid and hydroxycinnamic acid contents were determined by spectrophotometric analysis, as well as antioxidant activity tests. Organic acids and single polyphenols were also determined by HPLC. The results of the trial, characterized by moderate infection pressure, indicate that all tested products guaranteed a satisfactory control of Plasmopara viticola although the alternatives to copper were not as effective as copper. Data evidence that grape quality and its oenological potential were not significantly influenced by applied treatments and that they did not significantly differ in comparison with the untreated control, only with an interesting significant negative correlation between proanthocyanidins level and the severity of disease on ripe berries. The uniformity of data seems to evidence a general adaptation of plants to different treatment stresses, probably due both to low input of active ingredients and to moderate downy mildew infection.