Methyl salicylate glycosides in some Italian varietal wines

Glycosides are ubiquitous plant secondary metabolites consisting of a non-sugar component called an aglycone, attached to one or more sugars. One of the most interesting aglycones in grapes and wine is methyl salicylate (MeSA), an organic ester naturally produced by many plants, particularly wintergreens. To date, nine different MeSA glycosides from plants have been reported, mainly spread over the genera Gaultheria, Camellia, Polygala, Filipendula, and Passiflora. From a sensorial point of view, MeSA has a balsamic-sweet odor, known as Wintergreen. MeSA was found in Vitis riparia grapes, in Vitis vinifera sp. and in the Frontenac interspecific hybrid. We found that the MeSA glycosides content in Verdicchio wines and in some genetically related varieties (Trebbiano di Soave and Trebbiano di Lugana) was very high. In order to understand which glycosides were present in wine, the methanolic extract of Verdicchio wine was injected into a UPLC-Q-TOF-HDMS and compared to the extracts of different plants rich in such glycosides. Using pure standards, we confirmed the existence of two glycosides in wine: MeSA 2-O-β-d-glucoside and MeSA 2-O-β-d-xylopyranosyl (1-6) β-d-glucopyranoside (gaultherin). For the first time, we also tentatively identified other diglycosides in wine: MeSA 2-O-α-l-arabinopyranosyl (1-6)-β-d-glucopyranoside (violutoside) and MeSA 2-O-β-d-apiofuranosyl (1-6)-β-d-glucopyranoside (canthoside A), MeSA 2-O-β-d-glucopyranosyl (1-6)-O-β-d-glucopyranoside (gentiobioside) and MeSA 2-O-α-l-rhamnopyranosyl (1-6)-β-d-glucopyranoside (rutinoside). Some of these glycosides have been isolated from Gaultheria procumbens leaves by preparative liquid chromatography and structurally annotated by 1H- and 13C-NMR analysis. Two of the peaks isolated from Gaultheria procumbens leaves, namely MeSA sambubioside and MeSA sophoroside, were herein observed for the first time. Six MeSA glycosides were quantified in 64 Italian white wines, highlighting the peculiar content and pattern in Verdicchio wines and related cultivars. The total concentration in bound and free MeSA in Verdicchio wines varied in the range of 456–9796 μg/L and 5.5–143 μg/L, respectively, while in the other wines the bound and free MeSA was below 363 μg/L and 12 μg/L, respectively. As this compound’s olfactory threshold is between 50 and 100 μg/L, our data support the hypothesis that methyl salicylate can contribute to the balsamic scent, especially in old Verdicchio wine

Combining molecular and metabolomic analysis to evaluate transgenic Vitis vinifera plants expressing the Vitreoscilla haemoglobin (VHb)

Transgenic V. vinifera 'Brachetto' plants expressing Vitreoscilla stercoraria haemoglobin gene (vhb) were obtained by transferring the pBI-VHb construct harbouring the vhb and the nptII genes, via A. tumefaciens EAH 105. From 18 distinct transgenic plantlets, 2 lines were randomly chosen and 11 and 14 plants respectively obtained by micropropagation were acclimated for 100 days in the greenhouse, together with 10 micropropagated plants of a wild-type control line. A data-driven assessment, aimed at evaluating all measurable lowmolecular weight organic compounds in these transgenic plants was performed using UPLC-Q-TOF with an ESI interface. Comparisons between controls and transgenic lines and between the two transgenic lines detected significant differences in some metabolic patterns. For each line, a list of identified compounds was extracted from the 100 most significant biomarkers

Influence of harvest date on multi-targeted metabolomic profile and sensory attributes of Ribolla Gialla base and sparkling wines

In addition to a balanced production level, the timing of grape harvest is a crucial factor to be considered for the winemaking process of sparkling wines. A sufficient accumulation of sugars and an optimal level of acidity in grapes throughout ripening is necessary not only to achieve the desired alcohol levels in the wine but also to guarantee the biosynthesis of the aromatic precursors. To target optimal grape ripeness and maximise the positive sensory attributes of the wine produced, the work presented herein deals with a study on whether an extended harvest date might have a greater positive organoleptic impact and lead to an increase in important odour–impact compounds. In the resulting Ribolla Gialla monovarietal sparkling wines, a one-week delay after reaching technological maturity of the grapes expressed an improvement in the aromatic profile in the obtained samples by altering the profile and abundance of grape-derived compounds and fermentative esters. This was consequently reflected in the sensory evaluation, as the wines achieved higher scores for ‘floral’, ‘citrus fruit’, and ‘yeast’ sensory descriptors when the grapes were harvested a week after the minimum compromise between total acidity concentration and total soluble solids. Moreover, an extension of the harvest date is not necessarily correlated with the formation of untypical ageing off-flavour substances that could be detrimental to the quality of sparkling wines. Conversely, the lipid content proved to be more dependent on the climatic factors of the individual vintage compared to subsequent harvest time. By merging a multi-targeted approach of exploring wine metabolites and sensory characteristics, it is thus possible to predict an optimal harvest date for obtaining high-quality Ribolla Gialla sparkling wine

Myrtle Seeds (Myrtus communis L.) as a Rich Source of the Bioactive Ellagitannins Oenothein B and Eugeniflorin D2

The increasing popularity of "Mirto" liqueur, produced from Myrtus communis berries, has led to the planting of domesticated cultivars, expanding myrtle berry production. To promote the use of cultivated berries, the content in the nutraceutical compounds ellagitannins has been investigated both in spontaneous and cultivated fruits. Oenothein B and eugeniflorin D2, characterized by 1H and 13C NMR, were isolated and quantified using ultrahigh-performance liquid chromatography-diode array detector-tandem mass spectrometry (UPLC-DAD-MS/MS). The antifungal and anti-inflammatory activities of oenothein B were assayed in vitro. Large amounts of oenothein B and eugeniflorin D2 were detected in seeds (12 \ub1 2.4 and 5.8 \ub1 1.2 mg/g). The oenothein B concentration in liqueurs was 194 \ub1 22 mg/L. This macrocyclic ellagitannin dimer showed anti-Candida (minimal inhibitory concentration <8-64 \u3bcg/mL) and anti-inflammatory properties. Cultivated myrtle berries are a source of nutraceutical compounds. The high concentration of oenothein B in liqueur suggests a possible contribution to the organoleptic and biological properties of the beverage

Semi-Targeted Profiling of the Lipidome Changes Induced by Erysiphe Necator in Disease-Resistant and Vitis vinifera L. Varieties

The ascomycete Erysiphe necator is a serious pathogen in viticulture. Despite the fact that some grapevine genotypes exhibit mono-locus or pyramided resistance to this fungus, the lipidomics basis of these genotypes’ defense mechanisms remains unknown. Lipid molecules have critical functions in plant defenses, acting as structural barriers in the cell wall that limit pathogen access or as signaling molecules after stress responses that may regulate innate plant immunity. To unravel and better understand their involvement in plant defense, we used a novel approach of ultra-high performance liquid chromatography (UHPLC)-MS/MS to study how E. necator infection changes the lipid profile of genotypes with different sources of resistance, including BC4 (Run1), “Kishmish vatkhana” (Ren1), F26P92 (Ren3; Ren9), and “Teroldego” (a susceptible genotype), at 0, 24, and 48 hpi. The lipidome alterations were most visible at 24 hpi for BC4 and F26P92, and at 48 hpi for “Kishmish vatkhana”. Among the most abundant lipids in grapevine leaves were the extra-plastidial lipids: glycerophosphocholine (PCs), glycerophosphoethanolamine (PEs) and the signaling lipids: glycerophosphates (Pas) and glycerophosphoinositols (PIs), followed by the plastid lipids: glycerophosphoglycerols (PGs), monogalactosyldiacylglycerols (MGDGs), and digalactosyldiacylglycerols (DGDGs) and, in lower amounts lyso-glycerophosphocholines (LPCs), lyso-glycerophosphoglycerols (LPGs), lyso-glycerophosphoinositols (LPIs), and lyso-glycerophosphoethanolamine (LPEs). Furthermore, the three resistant genotypes had the most prevalent down-accumulated lipid classes, while the susceptible genotype had the most prevalent up-accumulated lipid classes