Variety features differentiate microbiota in the grape leaves.

The dependence of plant health and crop quality on the epiphytic microbial community has been extensively addressed, but little is known about plant-associated microbial communities under natural conditions. In this study, the bacterial and fungal communities on grape leaves were analyzed by 16S rRNA gene and internal transcribed spacer high-throughput sequencing, respectively. The results showed differences in the composition of the microbial communities on leaf samples of nine wine grape varieties. The most abundant bacterial genus was Pseudomonas, and the top three varieties with Pseudomonas were Zinfandel (22.6%), Syrah (21.6%), and Merlot (13.5%). The most abundant fungal genus was Alternaria, and the cultivar with the lowest abundance of Alternaria was Zinfandel (33.6%), indicating that these communities had different habitat preferences. The linear discriminant analysis effect size of all species showed that the bacteria Enterococcus, Massilia, and Kocuria were significantly enriched on the leaves of Merlot, Syrah, Cabernet Sauvignon, respectively; Pseudomonadales and Pantoea on Zinfandel; and Bacillus, Turicibacter, and Romboutsia on Pinot Noir. Similarly, the fungi Cladosporium, Phoma, and Sporormiella were significantly enriched on Zinfandel, Lon, and Gem, respectively. Both Bray-Curtis and unweighted UniFrac revealed that bacteria and fungi have a significant impact (P < 0.01), and the results further proved that variety is the most important factor affecting the microbial community. The findings indicate that some beneficial or harmful microorganisms existing on the wine grape leaves might affect the health of the grape plants and the wine-making process.

UHPLC-HR-MS/MS-Guided Recovery of Bioactive Flavonol Compounds from Greco di Tufo Vine Leaves.

Leaves of Vitis vinifera cv. Greco di Tufo, a precious waste made in the Campania Region (Italy), after vintage harvest, underwent reduction, lyophilization, and ultrasound-assisted maceration in ethanol. The alcoholic extract, as evidenced by a preliminary UHPLC-HR-MS analysis, showed a high metabolic complexity. Thus, the extract was fractionated, obtaining, among others, a fraction enriched in flavonol glycosides and glycuronides. Myricetin, quercetin, kaempferol, and isorhamnetin derivatives were tentatively identified based on their relative retention time and TOF-MS2 data. As the localization of saccharidic moiety in glycuronide compounds proved to be difficult due to the lack of well-established fragmentation pattern and/or the absence of characteristic key fragments, to obtain useful MS information and to eliminate matrix effect redundancies, the isolation of the most abundant extract's compound was achieved. HR-MS/MS spectra of the compound, quercetin-3-O-glucuronide, allowed us to thoroughly rationalize its fragmentation pattern, and to unravel the main differences between MS/MS behavior of flavonol glycosides and glycuronides. Furthermore, cytotoxicity assessment on the (poly)phenol rich fraction and the pure isolated compound was carried out using central nervous system cell lines. The chemoprotective effect of both the (poly)phenol fraction and quercetin-3-O-glucuronide was evaluated.

Total Phenols from Grape Leaves Counteract Cell Proliferation and Modulate Apoptosis-Related Gene Expression in MCF-7 and HepG2 Human Cancer Cell Lines.

Grape leaves influence several biological activities in the cardiovascular system, acting as antioxidants. In this study, we aimed at evaluating the effect of ethanolic and water extracts from grape leaves grown in Algeria, obtained by accelerator solvent extraction (ASE), on cell proliferation. The amount of total phenols was determined using the modified Folin-Ciocalteu method, antioxidant activities were evaluated by the 2,2-diphenyl-l-picrylhydrazyl free radical (DPPH*) method and ·OH radical scavenging using electron paramagnetic resonance (EPR) spectroscopy methods. Cell proliferation of HepG2 hepatocarcinoma, MCF-7 human breast cancer cells and vein human umbilical (HUVEC) cells, as control for normal cell growth, was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay (MTT). Apoptosis- related genes were determined by measuring Bax and Bcl-2 mRNA expression levels. Accelerator solvent extractor yield did not show significant difference between the two solvents (ethanol and water) (p > 0.05). Total phenolic content of water and ethanolic extracts was 55.41 ± 0.11 and 155.73 ± 1.20 mg of gallic acid equivalents/g of dry weight, respectively. Ethanolic extracts showed larger amounts of total phenols as compared to water extracts and interesting antioxidant activity. HepG2 and MCF-7 cell proliferation decreased with increasing concentration of extracts (0.5, 1, and 2 mg/mL) added to the culture during a period of 1⁻72 h. In addition, the expression of the pro-apoptotic gene Bax was increased and that of the anti-apoptotic gene Bcl-2 was decreased in a dose-dependent manner, when both MCF-7 and HepG2 cells were cultured with one of the two extracts for 72 h. None of the extracts elicited toxic effects on vein umbilical HUVEC cells, highlighting the high specificity of the antiproliferative effect, targeting only cancer cells. Finally, our results suggested that ASE crude extract from grape leaves represents a source of bioactive compounds such as phenols, with potential antioxidants activity, disclosing a novel antiproliferative effect affecting only HepG2 and MCF-7 tumor cells.

Valorization of grape (Vitis vinifera) leaves for bioactive compounds: novel green extraction technologies and food-pharma applications.

Grape leaves, scientifically known as Vitis vinifera, the primary by-product obtained after the processing of grapes, are gathered in enormous amounts and disposed of as agricultural waste. For more sustainable agriculture and better food systems, it is crucial to investigate these byproducts' nutritional values. The primary bioactive compounds present in grape leaves are quercetin, resveratrol, caffeic acid, kaempferol, and gallic acid, which favour pharmacological effects on human health such as antioxidant, anti-inflammatory, anti-obesity, anti-diabetic, and hepatoprotective. Furthermore, grape leaves extract has been used as a functional ingredient for creating both food and non-food products. The aim of the current review is to review the nutritional and phytochemical composition of various varieties of grape leaves, their health-promoting characteristics and their applications. The study also highlights the various extraction techniques including conventional and non-conventional methods for extracting the various bioactive compounds present in grape leaves. Grape leaves bioactives can be extracted using environmentally safe and sustainable processes, which are in line with the rising demand for eco-friendly and healthful products worldwide. These methods are perfectly suited to the changing needs of both customers and industries since they lessen environmental effect, enhance product quality, and offer financial advantages.

Bio-synthesis of TiO2 using grape leaves extract and its application for photocatalytic degradation of ibuprofen from aqueous solution.

ABSTRACTIn this study, titanium oxide nanoparticle was fabricated using the extract of grape leaves (referred asGL-TiO2 NPs), using the green synthesis process, and then explores its ability for photodegradation of ibuprofen (IBU) under UV light in the batch system. UV-Vis, BET, FTIR, XRD, and SEM-EDX tests were made to identify the catalyst's structure and shape. Moreover, the effects of different operating parameters, specifically pH of (3, 5, 7, and 9), IBU concentration (10, 20, 40, and 80) mg/L, GL-TiO2 concentrations (15, 30, and 60) mg/L, H2O2 (100, 300, and 500) mg/L, and contact time were studied. According to the results, the synthetic TiO2 NPs have a spherical shape and 39.608 m2/g of BET surface area. In addition, the findings showed that the removal efficiency reached 92.32% under optimum conditions of 5, 10, 30, 300 mg/L, and 150 min, respectively. In addition, the reaction followed a first-order kinetics model with R2 > 97. According to the finding of this study, GL-TiO2 NPs has an acceptable efficiency in the elimination of IBU, as their relatively simple synthesis, could be a suitable catalyst for the degradation and elimination of pharmaceutical residues.

Quercetin 3-O-Glucuronide from Aglianico Vine Leaves: A Selective Sustainable Recovery and Accumulation Monitoring.

In recent years, as part of sustainable development policies, the revaluation of end-of-life products has become more and more widespread. In terms of sustainability, in a scenario of circular economy food sustainability aims, inter alia, at making an effective re-use of natural resources as a starting point for the obtainment of high added-value products. With the aim of promoting the valorization of the wine sector wastes, the present study took into account the leaves of Vitis vinifera L. cv. Aglianico from the Campania Region (Italy). The use of deep eutectic solvents as a greener alternative to the most common organic solvents, joint to ultrasound-assisted maceration, and LC-MS tools, allowed us to define for the first time a six-month quantitative variation of flavonol derivatives, and in particular of quercetin 3-O-glucuronide, based on the collection time and the leaf height on the grapevine. Results underlined that the influence of abiotic factors, such as exposure to sunlight, which is pivotal in the biosynthesis of such compounds, should be strictly considered for their full recovery.

Residual pesticides in grape leaves (Vitis vinifera L.) on the Egyptian market and human health risk.

A QuEChERS method, followed by GC-MS/MS and LC-MS/MS was used for determining more than 400 pesticide residues in grape leaves collected from the Egyptian markets during the 2021 summer season. Seventy-eight samples contained 36 pesticide residues of different chemical groups above the EU-MRLs. Fungicides were the most frequently detected pesticides (59%), followed by insecticides (35%) and herbicides (5%).Hazard Quotients and Hazard Indexes were calculated where the results showed that both do not pose any health risk to consumers. Furthermore, cumulative risk assessment parameters (cHI) according to pesticide chemical group were calculated, resulting in 0.06, 0.09, 0.20, 0.28, 0.7 and 1.1% for strobin, organophosphorus, neonicotinoid, pyrethroid, benzimidazole and azole compounds, respectively. Fungicides were the major contributors to cHI, above insecticides by a factor of 2.7. Hence, there is a need for continuous survey and monitoring to protects consumers from exposure to unauthorized substances such as carbendazim, benomyl and profenofos.

Effect of Natural Antioxidants from Fruit Leaves on the Oxidative Stability of Soybean Oil during Accelerated Storage.

Plant by-products are safe, sustainable, and abundant natural antioxidant sources. Here we investigated the antioxidant activity of a mixture of lyophilized pomegranate, guava, and grape (PGG) leaves water extract (1:1:1) and examined its ability to retard the rancidity of soybean oil during accelerated storage at 65 °C for 30 days. To achieve this, we evaluated the oxidative stability of soybean oil enriched with PGG extract at 200, 400, and 800 ppm. We also compared the effect of PGG extract with butylated hydroxytoluene (BHT) (400/100 ppm) with that of only BHT (200 ppm). We observed that 8.19 and 1.78 µg/mL of the extract could scavenge 50% of DPPH• and ABTS•, respectively, indicating its enhanced antioxidant activity. Enriching soyabean oil with the extract at 800 ppm improved its oxidative stability by reducing the acid value to 1.71 mg/g and the total oxidation to 99.87 compared to 2.27 mg/g and 150.32 in the raw oil, respectively. Moreover, PGG-800 ppm inhibited oxidation by 46.07%. Similarly, PGG-400 ppm reinforced BHT (100 ppm) to provide oxidative stability as BHT (p > 0.05), with TOTOX values of 87.93 and 79.23, respectively. PGG-800 ppm and PGG/BHT mix potently inhibited the transformation of polyunsaturated fatty acids into saturated ones. Therefore, the PGG extract might be an efficient substitute for BHT (partially or totally) during industrial processes.

Melatonin Relieves Ozone Stress in Grape Leaves by Inhibiting Ethylene Biosynthesis.

Ozone (O3) stress severely affects the normal growth of grape (Vitis vinifera L.) leaves. Melatonin (MT) plays a significant role in plant response to various abiotic stresses, but its role in O3 stress and related mechanisms are poorly understood. In order to understand the mechanism of MT in alleviate O3 stress in grape leaves, we perform a transcriptome analyses of grapes leaves under O3 stress with or without MT treatment. Transcriptome analysis showed that the processes of ethylene biosynthesis and signaling were clearly changed in "Cabernet Sauvignon" grapes under O3 and MT treatment. O3 stress induced the expression of genes related to ethylene biosynthesis and signal transduction, while MT treatment significantly inhibited the ethylene response mediated by O3 stress. Further experiments showed that both MT and aminoethoxyvinylglycine (AVG, an inhibitor of ethylene biosynthesis) enhanced the photosynthetic and antioxidant capacities of grape leaves under O3 stress, while ethephon inhibited those capacities. The combined treatment effect of MT and ethylene inhibitor was similar to that of MT alone. Exogenous MT reduced ethylene production in grape leaves under O3 stress, while ethephon and ethylene inhibitors had little effect on the MT content of grape leaves after O3 stress. However, overexpression of VvACO2 (1-aminocyclopropane-1-carboxylate oxidase2) in grape leaves endogenously induced ethylene accumulation and aggravated O3 stress. Overexpression of the MT synthesis gene VvASMT1 (acetylserotonin methyltransferase1) in tobacco (Nicotiana tabacum L.) alleviated O3 stress and reduced ethylene biosynthesis after O3 stress. In summary, MT can alleviate O3 stress in grape leaves by inhibiting ethylene biosynthesis.

Application of a hyperspectral imaging system to quantify leaf-scale chlorophyll, nitrogen and chlorophyll fluorescence parameters in grapevine.

Rapidly and accurately monitoring the physiological and biochemical parameters of grape leaves is the key to controlling the quality of wine grapes. In this study, a Pika L hyperspectral imaging system (400-1000 nm) was used to acquire hyperspectral image information from grape leaves. New vegetation indices were developed on the basis of the screened sensitive wavebands to quantitatively predict changes in these parameters (the leaf chlorophyll level (SPAD), leaf nitrogen content (LNC) and chlorophyll fluorescence parameters (ChlF parameters)). The results showed that SPAD reached its maximum at the grape turning stage and declined thereafter. The vegetation index (D735-D573)/(D735+D573) was able to predict SPAD fairly well (validation dataset R2 = 0.50). LNC reached its maximum at the grape maturity stage. D682/R525 was highly correlated with LNC. Except for NPQ, all ChlF parameters showed a decreasing trend from the fruiting to harvesting stages. Among the dark-adapted ChlF parameters, FV/Fm had the strongest correlation to the new vegetation index (D735-D544)/(D735+D544) (modelling dataset R2 = 0.68), and Fo had the weakest correlation. Among the light-adapted ChlF parameters, Y(II) had the strongest correlation to the new vegetation index D676/R571 (validation dataset R2 = 0.63); this index also had good predictive power for Fm' (validation dataset R2 = 0.52) but low predictive power for Fo'. All the calculated vegetation indices had weak relationships with NPQ. In addition, this study also verified the predictive abilities of vegetation indices developed in previous studies. This study can provide a technical basis for the nondestructive monitoring of the physiological and biochemical parameters of grape leaves with hyperspectral imaging systems.

Potential use of secondary products of the agri-food industry for topical formulations and comparative analysis of antioxidant activity of grape leaf polyphenols.

The aim of the present study was to develop a phytocosmetic using Vitis waste by-products, for use as a topical formulation for skin protection against ultraviolet radiation damage. The study also evaluates the free radical scavenger activity of the crude extracts of dried leaves of Vitis vinifera and Vitis labrusca, as well as the anthocyanins, flavonoid fraction and isolated compounds. Next, release and permeation studies of hydrogels were performed using Franz-type diffusion cells. Flavonoid acted more intensively in TRAP and conjugated dienes antioxidant assays, whereas anthocyanins had higher antioxidant activity in hydroxyl and nitric oxide assay. Only quercetin-3-O-glucuronide (5) was released from hydrogels, and the flavonoid retention in porcine ear skin after eight hours of permeation was below of limit of quantification for this compound. The polyphenols present in Vitis are capable of absorbing UV and visible light, justifying their potential as sunscreens for the development of a phytocosmetic.

Modification of the existing maximum residue levels for sulfoxaflor in grape leaves and similar species, and globe artichokes.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Dow AgroSciences Ltd submitted two separate requests to the competent national authority in France to modify the existing maximum residue levels (MRLs) for the active substance sulfoxaflor in grape leaves and globe artichokes. The data submitted in support of the requests were found to be sufficient to derive MRLs proposals of 2 mg/kg in grape leaves and similar species and of 0.06 mg/kg in globe artichokes. Adequate analytical methods for enforcement are available to control the residues of sulfoxaflor in the commodities under consideration. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the uses of sulfoxaflor on grape leaves and similar species and globe artichokes according to the reported agricultural practices is unlikely to present a risk to consumers' health.