Constitutive Polyphenols in Blades and Veins of Grapevine (Vitis vinifera L.) Healthy Leaves

Abstract

Despite the economic importance and the diffusion of grapevine cultivation worldwide, little is known about leaf chemical composition. We characterized the phenolic composition of Nebbiolo, Barbera, Pinot noir, Cabernet Sauvignon, Grenache, and Shiraz ( Vitis vinifera L.) healthy leaves (separating blades and veins) during the season. Quantitative and qualitative differences were found between leaf sectors and among genotypes. In healthy grapevine leaves, anthocyanins, dihydromyricetin-rhamnoside, hexosides of dihydroquercetin, and dihydrokaempferol exclusively accumulated in veins. Astilbin was the only flavanonol detected in blades and the prevalent flavanonol in veins. Barbera distinguished for the lowest proanthocyanidin and the highest hydroxycinnamate content, and Pinot noir for the absence of acylated-anthocyanins. Nebbiolo, and Cabernet Sauvignon displayed a high concentration of epigallocatechin gallate in veins. Nebbiolo leaves showed the highest concentrations of flavanonols and the widest profile differentiation. Knowledge derived from the present work is a contribution to find out leaf polyphenol potential as a part of grapevine defense mechanisms and to dissect genotype-related susceptibility to pathogens; moreover, it represents a starting point for future deepening about grapevine and vineyard byproducts as a source of bioactive phenolic compounds.

Polyphenolic diversity in Vitis sp. leaves

“…The Eurasian wild species V. v. sylvestris, the ancestor of the worldwide cultivated V. vinifera sativa, accumulated relatively high concentration of total polyphenols and total phenolic acids (Figure 2; Figure 5). Among phenolic acids, the predominant non-flavonoid polyphenols, caftaric acid was the prevalent form, representing up to 90% of total phenolic acids (Figure 5C), similarly to what was previously assessed in V. vinifera sativa leaves (Kedrina-Okutan et al, 2018). Caftaric acid is an important bioactive component found in chicory, in the medical plant Echinacea purpurea (Bel-Rhlid et al, 2012) and, in V. coignetiae juice, where it exhibited anti-mutagenic and anti-inflammatory properties (Kamiya et al, 2018).…”

“…Moreover, also the concentration of (-)-epicatechin was particularly high. This compound was previously individuated as a reaction of pear leaves against Erwinia amylovora and of apple leaves against Venturia inaequalis (as discussed in Kedrina-Okutan et al, 2018). In non-Vitis vinifera genotypes, (-)-epigallocatechin was additionally detected with increasing concentration during the vegetative season (Figure 6).…”

“…The studied Vitis genotype leaves were collected in the collection vineyard of DISAFA, University of Turin, Grugliasco (Piedmont, Italy), sampled five times during the season: 1 = 28 th of May (148 day of the year -DOY), 2 = 22 nd of June (DOY 173), 3 = 14 th of July (DOY 195), 4 = 3 rd of August (DOY 215), 5 = 28 th of August (DOY 214), in 2015. The collection vineyard was managed routinely during spring and summer as already described (Kedrina-Okutan et al, 2018) ( Kedrina-Okutan et al, 2018). One field parcel was generally constituted by four consecutive plants used to collect the leaves; leaves were detached between the fourth and seventh node of the main shoots from the west side of the row.…”

Analysis of Flavonoid Metabolites in Citrus Peels (Citrus reticulata “Dahongpao”) Using UPLC-ESI-MS/MS

“…Dihydroquercetin, as an important flavonoid, exists in many plants and has a high content of larch , especially Pinus elliottii [30]. In recent years, dihydroquercetin has also been found in fruits, especially grapes [31] and oranges [32]. Anthocyanin is a kind of water-soluble natural pigment widely found in plants in nature, which is also a powerful antioxidant that can protect against harmful substances [33].…”

Protective Effects of Some Grapevine Polyphenols against Naturally Occurring Neuronal Death

“…First, researchers at times have tested the effects of pure molecules but, other times, those of crude plant extracts, with a substantial heterogeneity of results that have been difficult to compare because very often the concentrations of the individual PPs in extracts were unknown. Second, certain experiments used the PPs obtained from different grapevine organs, which contain very heterogeneous levels of these molecules, as it occurs, for example, for leaves compared to other organs of the grapevine [6,7]. Third, starting from different sources of PPs (wines) diverse extraction methods were reported to display very different degrees of efficiency, and to produce chemically heterogeneous extracts when the effects of three critical variables (sample volume, volume of each eluent, and solvent percentage in eluent) were evaluated for non-polymeric phenol and tannin recoveries from wine [8].…”