Rosa Anna Milella

HPLC-DAD-ESI-MS Analysis of Flavonoid Compounds in 5 Seedless Table Grapes Grown in Apulian Region

UNLABELLED Flavonoids present in skin extracts of red seedless table grape varieties Summer Royal, Autumn Royal, and Crimson, and white seedless varieties Carati and Thompson were analyzed by HPLC-DAD-MS, in 3 y of study (2006 to 2008). The anthocyanins, delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside (with their corresponding p-coumaroyl derivatives), peonidin-3-O-glucoside, and malvidin-3-O-glucoside (with their corresponding acetyl, caffeoyl, and p-coumaroyl derivatives) were found. In addition the flavonols quercetin-3-O-glucuronide, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, kaempferol-3-O-galactoside, and the flavan-3-ols procyanidin B1, procyanidin B2, and catechin were also detected. Anthocyanins were the main flavonoids in red grapes ranging from 24 (Crimson) to 500 (Summer Royal) mg/kg fresh weight of grapes; consistent levels of flavonols and flavan-3-ols were also quantified in all varieties. To determine the effective climatic influence on flavonoids content in field conditions, viticultural practices have been developed, that could exclude the effects of direct solar radiation from confounding the assessment of those related to thermal conditions alone. A strong positive correlation was determined between flavonoids and temperature data that seem to be responsible for the difference of these metabolites along the years; furthermore, it has been possible to define a linear relationship (R(2) = 0.6871, P = 0.0057) between thermal amplitude and total flavonoids values in the red grapes. PRACTICAL APPLICATION Grapes are economically the most important fruit species in the world and approximately 30% of its production is used as fresh fruit. Because of the very important role of flavonoids in food quality as well as their health-promoting properties, and considering that our experiments were performed along 3 consecutive years, gathered results in this research are quite promising to give a useful information on the flavonoid contents and their evolution in 5 seedless table grapes that are widespread in Mediterranean regions but also in California and South America, and are grown in a viticultural climate (Apulia, South Italy) very close to some regions of Spain, Turkey, Tunisia, and Israel.

Antithrombotic activity of 12 table grape varieties. Relationship with polyphenolic profile

The synthesis of tissue factor (TF) by monocytes/macrophages activated by inflammatory agents is of utmost importance in the pathogenesis of thrombotic diseases and substances inhibiting TF synthesis represent novel and promising antithrombotics. We investigated the effect of 12 table grape varieties (white, red and black) on TF synthesis and the possible relation with the phenolic profile. The ability of grape skin extracts (GSEs) to inhibit TF was evaluated in whole blood and isolated mononuclear cells challenged with endotoxin. TF expression was assayed by functional and immunological assays. All GSEs inhibited TF synthesis but with a different efficiency, red grapes being the most active. By correlation analysis, the compounds showing the strongest association with TF-inhibiting activity were quercetin and cyanidin. However, no single polyphenol was able to inhibit TF synthesis as efficiently as the crude grape extracts, unless it was combined with at least another compound, suggesting a synergism.

Phenolic content and in vitro antifungal activity of unripe grape extracts from agro-industrial wastes

Abstract The antifungal activity of unripe grape extracts from agro-industrial wastes has been evaluated against several strains of Candida spp. and dermatophytes. All the extracts tested showed antifungal activity. The geometric mean MIC ranged from 53.58 to 214.31 μg/mL for Candida spp. and from 43.54 to 133.02 μg/mL for dermatophytes. The chemical analyses have been carried out using Liquid Chromatograph equipped with a DAD and MS detectors. Flavan-3-ols were the main metabolites within all samples ranged from 3.3 to 6.8 mg/g fresh weight. For Candida spp. highest negative significant correlation has been found between MICs and polymeric flavan-3-ols (r = −0.842; p < 0.001) and for dermatophytes between MICs and caffeoyl derivatives (r = −0.962; p < 0.01). The results indicate that total extracts obtained from unripe grapes, a large source of waste material derived from the wine industry, could be used as a cheap source of value-added products.