Giovanna Giovinazzo

Resveratrol inhibits the epidermal growth factor-induced epithelial mesenchymal transition in MCF-7 cells

Carcinoma progression is associated with the loss of epithelial features, and the acquisition of a mesenchymal phenotype by tumour cells. Herein we show that exposure of MCF-7 cells to epidermal growth factor (EGF) resulted in morphological alterations characteristic of epithelial-to-mesenchymal transition (EMT). EGF treatment resulted in increased motility along with an up-regulation of transcription factors Slug, Zeb1, Zeb2, and mesenchymal markers Vimentin and N-cadherin. Treatment of MCF-7 cells with a combined stimulation of EGF and resveratrol, a naturally occurring stilbene with antitumor properties, failed to alter cell morphology, motility and overexpression of EMT markers induced by EGF. Using specific chemical inhibitors, we demonstrated that EGF-induced EMT is mediated by extracellular signal-regulated kinase 1/2 (ERK 1/2) signalling pathway and that resveratrol is able to repress EGF-induced ERK activation. In summary, these data provide new evidence of the inhibitory effect of resveratrol on EGF-induced EMT cell transformation.

Resveratrol Biosynthesis: Plant Metabolic Engineering for Nutritional Improvement of Food

The plant polyphenol trans-resveratrol (3, 5, 4′-trihydroxystilbene) mainly found in grape, peanut and other few plants, displays a wide range of biological effects. Numerous in vitro studies have described various biological effects of resveratrol. In order to provide more information regarding absorption, metabolism, and bioavailability of resveratrol, various research approaches have been performed, including in vitro, ex vivo, and in vivo models. In recent years, the induction of resveratrol synthesis in plants which normally do not accumulate such polyphenol, has been successfully achieved by molecular engineering. In this context, the ectopic production of resveratrol has been reported to have positive effects both on plant resistance to biotic stress and the enhancement of the nutritional value of several widely consumed fruits and vegetables. The metabolic engineering of plants offers the opportunity to change the content of specific phytonutrients in plant - derived foods. This review focuses on the latest findings regarding on resveratrol bioproduction and its effects on the prevention of the major pathological conditions in man.

Antioxidant and anti-inflammatory properties of tomato fruits synthesizing different amounts of stilbenes.

Resveratrol, a plant phenolic compound, is found in grapes and red wine, but is not widely distributed in other common food sources. The pathway for resveratrol biosynthesis is well characterized. Metabolic engineering of this compound has been achieved in tomato plants (Lycopersicon esculentum Mill.) in order to improve their nutritional value. Tomato plants synthesizing resveratrol were obtained via the heterologous expression of a grape (Vitis vinifera L.) cDNA encoding for the enzyme stilbene synthase (StSy), under the control of the fruit-specific promoter TomLoxB. The resulting LoxS transgenic plants accumulated trans-resveratrol and trans-piceid, in particular in the skin of the mature fruits. Quantitative analyses carried out on LoxS fruits were compared with those of a tomato line constitutively expressing the stsy gene (35SS). The LoxS fruits contained levels of trans-resveratrol that were 20-fold lower than those previously reported for the 35SS line. The total antioxidant capability and ascorbate content in transformed fruits were also evaluated, and a significant increase in both was found in the LoxS and 35SS lines. These results could explain the higher capability of transgenic fruits to counteract the pro-inflammatory effects of phorbol ester in monocyte-macrophages via the inhibition of induced cyclo-oxygenase-2 enzyme.

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.

Red Grape Skin Polyphenols Blunt Matrix Metalloproteinase-2 and -9 Activity and Expression in Cell Models of Vascular Inflammation: Protective Role in Degenerative and Inflammatory Diseases

Matrix metalloproteinases (MMPs) are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases’ activity and expression are regulated by oxidative stress, we sought to evaluate whether supplementation with polyphenol-rich red grape skin extracts modulated the matrix-degrading capacity in cell models of vascular inflammation. Human endothelial and monocytic cells were incubated with increasing concentrations (0.5–25 μg/mL) of Negroamaro and Primitivo red grape skin polyphenolic extracts (NSPE and PSPE, respectively) or their specific components (0.5–25 μmol/L), before stimulation with inflammatory challenge. NSPE and PSPE inhibited, in a concentration-dependent manner, endothelial invasion as well as the MMP-9 and MMP-2 release in stimulated endothelial cells, and MMP-9 production in inflamed monocytes, without affecting tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2. The matrix degrading inhibitory capacity was the same for both NSPE and PSPE, despite their different polyphenolic profiles. Among the main polyphenols of grape skin extracts, trans-resveratrol, trans-piceid, kaempferol and quercetin exhibited the most significant inhibitory effects on matrix-degrading enzyme activities. Our findings appreciate the grape skins as rich source of polyphenols able to prevent the dysregulation of vascular remodelling affecting degenerative and inflammatory diseases.

Efficient stabilization of natural curcuminoids mediated by oil body encapsulation

Curcumin is a natural hydrophobic polyphenol found in the powdered rhizomes of Curcuma longa. Due to its capacity to interfere with many signalling pathways, it has been shown that curcumin has potential beneficial pharmacological effects including antioxidant, anti-inflammatory, anticarcinogenic properties. However, the use of curcumin is fairly restricted because of its poor water solubility, low bioavailability, inadequate tissue absorption and degradation at alkaline pH. In the present contribution, we first verified the anti-proliferative effects of natural curcuminoids towards two different cell lines derived from an ovarian and a breast adenocarcinoma cancer. Later, curcuminoids were successfully encapsulated into reconstituted oil bodies. Once encapsulated into the triacylglycerol cores of the reconstituted oil bodies, curcumin, the most hydrophobic and active of the three curcuminoids, was better stabilized in comparison with albumin stabilization. Oil body encapsulated curcuminoids showed the same effects on cancer cell viability as the free drug, confirming the great potential of natural oil bodies as micro/nano-capsules in drug delivery applications.

Gut Microbiota Modulation and Anti-Inflammatory Properties of Dietary Polyphenols in IBD: New and Consolidated Perspectives

BACKGROUND Polyphenols represent a great variety of compounds occurring in fruits, vegetables and plant-derived products. Dietary polyphenols have been found displaying several biological properties, such as anti-inflammatory, antioxidant and anti-aging activities, cardiovascular and neuro-protection, and reduction of the risk of intestinal diseases. The bio-efficacy of polyphenols is tightly linked to their bioavailability, to structural complexity and composition of food matrix in which they are present. Since most of the polyphenols are naturally stored in food matrices as glycosylated and/or variously decorated forms, they need an intestinal bio-conversion in more absorbable forms. Recent findings are highlighting the polyphenols-gut microbiota interplay in the health benefits linked to these compounds. Furthermore, the prebiotic-like activities of polyphenols on microbiota and their potential use in preventive/therapeutic strategies for gastrointestinal disorders are recently emerging. CONCLUSION In this review, we will focus on the dietary flavonols, anthocyanins and stilbenes, as widely occurring polyphenols in human diet, their metabolism mediated by gut microbiota and their protective effects on inflammatory bowel diseases (IBDs).

Combined Dietary Anthocyanins, Flavonols, and Stilbenoids Alleviate Inflammatory Bowel Disease Symptoms in Mice

Dietary polyphenols are associated with a wide range of health benefits, protecting against chronic diseases and promoting healthy aging. Dietary polyphenols offer a complementary approach to the treatment of inflammatory bowel diseases (IBDs), a group of common chronic intestinal inflammation syndromes for which there is no cure. Tomato is widely consumed but its content of polyphenols is low. We developed a tomato variety, Bronze, enriched in three distinct classes of polyphenols: flavonols, anthocyanins, and stilbenoids. Using Bronze tomatoes as a dietary supplement as well as Indigo (high anthocyanins and flavonols), ResTom (high stilbenoids) and wild-type tomatoes, we examined the effects of the different polyphenols on the host gut microbiota, inflammatory responses, and the symptoms of chronic IBD, in a mouse model. Bronze tomatoes significantly impacted the symptoms of IBD. A similar result was observed using diets supplemented with red grape skin containing flavonols, anthocyanins, and stilbenoids, suggesting that effective protection is provided by different classes of polyphenols acting synergistically.

Natural resveratrol bioproduction

Abstract: Polyphenols form a large family of plant secondary metabolites. Since they are abundant in fruits and vegetables, they form an integral part of the human diet. Diverse health-related effects are attributed to flavonoids, including scavenging of free radicals and modification of enzymatic activities. Consequently, the ingestion of different flavonoid species may be more beneficial for human health than the ingestion of only a few species. However, in most fruit and crop plants, only one or a few flavonoid classes are present. One group of polyphenols believed to have a positive effect on health is the flavonoid-related class of stilbenes, specifically trans-resveratrol and its glucoside piceid. trans-Resveratrol, mainly found in grape, peanut and a few other plants, displays a wide range of biological effects. There is growing interest in the development of plant cell cultures and food crops with tailor-made levels and composition of stilbenes, designed for optimal biological effect.