Grape Pomace Extract Attenuates Inflammatory Response in Intestinal Epithelial and Endothelial Cells: Potential Health-Promoting Properties in Bowel Inflammation.

Inflammatory bowel disease (IBD) implies the chronic inflammation of the gastrointestinal tract, combined with systemic vascular manifestations. In IBD, the incidence of cardiovascular disease appears to be related to an increase of oxidative stress and endothelial dysfunction. Grape pomace contains high levels of anti-oxidant polyphenols that are able to counteract chronic inflammatory symptoms. The aim of this study was to determine whether grape pomace polyphenolic extract (GPE) was able to mitigate the overwhelming inflammatory response in enterocyte-like cells and to improve vascular function. Intestinal epithelial Caco-2 cells, grown in monolayers or in co-culture with endothelial cells (Caco-2/HMEC-1), were treated with different concentrations of GPE (1, 5, 10 µg/mL gallic acid equivalents) for 2 h and then stimulated with lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α for 16 h. Through multiple assays, the expression of intestinal and endothelial inflammatory mediators, intracellular reactive oxygen species (ROS) levels and NF-κB activation, as well as endothelial-leukocyte adhesion, were evaluated. The results showed that GPE supplementation prevented, in a concentration-dependent manner, the intestinal expression and release of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and matrix metalloproteinases (MMP)-9 and MMP-2. In Caco-2 cells, GPE also suppressed the gene expression of several pro-inflammatory markers, such as IL-1ß, TNF-α, macrophage colony-stimulating factor (M-CSF), C-X-C motif ligand (CXCL)-10, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and cyclooxygenase (COX)-2. The GPE anti-inflammatory effect was mediated by the inhibition of NF-κB activity and reduced intracellular ROS levels. Furthermore, transepithelial GPE suppressed the endothelial expression of IL-6, MCP-1, VCAM-1, and ICAM-1 and the subsequent adhesion of leukocytes to the endothelial cells under pro-inflammatory conditions. In conclusion, our findings suggest grape pomace as a natural source of polyphenols with multiple health-promoting properties that could contribute to the mitigation of gut chronic inflammatory diseases and improve vascular endothelial function.

Comparison of Antibacterial and Antioxidant Properties of Red (cv. Negramaro) and White (cv. Fiano) Skin Pomace Extracts.

Wine pomace has attracted the attention of the food industry, due to its high content in bioactive compounds, and its multiple healthy activities. In this work, whole and separated skin pomaces from fermented (red) and un-fermented (white) grape by-products were characterized for their antioxidant and antimicrobial activities in order to exploit them as functional food ingredient. Antioxidant activity, measured by both ORAC and TEAC assays, was higher in whole than in skin pomace extracts. The characterization of phenolic composition in whole and skin pomace extracts confirmed the peculiarity of some compounds such as anthocyanins (107.84 + 10.3 mg/g TP) in red skin pomace and a great amount of flavanols (80.73 + 4.04 mg/g TP) in white skin pomace. Whole and skin pomace extracts displayed the same antibacterial activity at 250 µg gallic acid equivalents (GAE)/mL. Red and white skin pomace extracts showed a Minimum Inhibitory Concentration (MIC) of 31.25-62.5 GAE/mL against Staphylococcus aureus and Enterococcus faecalis. Pseudomonas spp. were more sensitive to red skin pomace extracts rather than white skin pomace extracts. Given these results, both red and white pomace extracts could be exploited for future application in food, pharmaceutical and cosmetic industry.

Can Natural Polyphenols Help in Reducing Cytokine Storm in COVID-19 Patients?

SARS-CoV-2 first emerged in China during late 2019 and rapidly spread all over the world. Alterations in the inflammatory cytokines pathway represent a strong signature during SARS-COV-2 infection and correlate with poor prognosis and severity of the illness. The hyper-activation of the immune system results in an acute severe systemic inflammatory response named cytokine release syndrome (CRS). No effective prophylactic or post-exposure treatments are available, although some anti-inflammatory compounds are currently in clinical trials. Studies of plant extracts and natural compounds show that polyphenols can play a beneficial role in the prevention and the progress of chronic diseases related to inflammation. The aim of this manuscript is to review the published background on the possible effectiveness of polyphenols to fight SARS-COV-2 infection, contributing to the reduction of inflammation. Here, some of the anti-inflammatory therapies are discussed and although great progress has been made though this year, there is no proven cytokine blocking agents for COVID currently used in clinical practice. In this regard, bioactive phytochemicals such as polyphenols may become promising tools to be used as adjuvants in the treatment of SARS-CoV-2 infection. Such nutrients, with anti-inflammatory and antioxidant properties, associated to classical anti-inflammatory drugs, could help in reducing the inflammation in patients with COVID-19.

Functional Properties of Grape and Wine Polyphenols.

Grape berries polyphenols are mainly synthesized in the skin tissues and seeds and they are extracted during the winemaking process. These substances have a potentially positive effect, on human health, thus giving to grape and red wine "functional properties" that can contribute to prevent a number of human illness. Nevertheless, the research community is showing that the real effect is a result of a combination of different factors, notably daily intake, bioavailability, or in vivo antioxidant activity that are yet to be resolved. Viticulture and winemaking practices, determine the concentration of polyphenols in grape and wine. To date, reduced knowledge is existing on the effects of different yeast strains on the final concentration of polyphenols in red wine. We summarize the recent findings concerning the effects of polyphenols on human chronic disease and the future directions for research to increase the amount of these compounds in wine.

Over-expression of a grape stilbene synthase gene in tomato induces parthenocarpy and causes abnormal pollen development.

A novel strategy to induce parthenocarpy in tomato fruits by the induction of resveratrol biosynthesis in flower tissues was exploited. Two transgenic tomato lines were considered: a higher resveratrol-producing (35SS) line, constitutively expressing a grape stilbene synthase cDNA, and a lower resveratrol-producing (LoxS) line, expressing stilbene synthase under a fruit-specific promoter. The expression of the stilbene synthase gene affected flavonoid metabolism in a different manner in the transgenic lines, and in one of these, the 35SS line, resulted in complete male sterility. Resveratrol was synthesised either in 35SS or LoxS tomato flowers, at an even higher extent (about 8-10 times) in the former line. We further investigated whether stilbene synthase expression may have resulted in impaired naringenin accumulation during flower development. In the 35SS flowers, naringenin was significantly impaired by about 50%, probably due to metabolic competition. Conversely, the amount of glycosylated flavonols increased in transgenic flowers, thereby excluding the diminished production of flavonols as a reason for parthenocarpy in tomato. We further investigated whether resveratrol synthesis may have resulted changes to pollen structure. Microscopic observations revealed the presence of few and abnormal flake-like pollen grains in 35SS flowers with no germination capability. Finally, the analysis of coumaric and ferulic acids, the precursors of lignin and sporopollenin biosynthesis, revealed significant depletion of these compounds, therefore suggesting an impairment in structural compounds as a reason for pollen ablation. These overall outcomes, to the best of our knowledge, reveal for the first time the major role displayed by resveratrol synthesis on parthenocarpy in tomato fruits.

Plant oil bodies: novel carriers to deliver lipophilic molecules.

Oil bodies (OBs) are specialised organelles ubiquitously detected in plant oil seeds, which serve as lipid storage compartments. OBs consist of a hydrophobic core of triacylglycerol (TAGs), surrounded by a monolayer of phospholipids (PLs) embedded with some specific proteins with a size ranging from 0.5 to 2 µm. In this work, we report an easy method to reconstitute OBs starting from their constituents and to encapsulate lipophilic molecules, i.e. the fluorescent fluorescein isothiocyanate (FITC) and carboxyfluorescein (CF), into reconstituted OBs. This methods allowed us to produce OBs 4- to 10-fold smaller (50-200 nm) than the native one and to obtain a good recovery (about 40%) of both the fluorescent compounds used in the present work. The properties of reconstituted OBs were investigated by a combination of Brewster angle microscopy, scanning force microscopy, ζ-potential techniques. OBs were stable and formed ordered monolayers when patterned on hydrophobic substrates whereas they showed a higher tendency to aggregate into larger, coalescing OBs when were deposited onto hydrophilic substrates or at the air/water interface. Furthermore, we verified the uptake of FITC-loaded OBs by the MCF-7 breast cancer cell line. Our results indicated that OBs could be envisaged as novel carriers to deliver hydrophobic bioactive compounds.