Antioxidant and Cytoprotective Activities of Grapevine Stilbenes

QbD-based formulation development of resveratrol nanocrystal incorporated into soluble mesoporous material: Pharmacokinetic proof of concept study

Resveratrol (RSV) has powerful antioxidant activities. However, the bioavailability is still limited due to low solubility and transport issues. Nanocrystal technology has been introduced to address these issues; however, the bulky formulation of the nanocrystal process through nanosuspension faces a big challenge in terms of stability and scale-up ability. This work aimed to enhance the bioavailability of RSV through nanocrystal formulation incorporated into soluble mesoporous carriers for superior solid-state stability and feasibility. This formulation was designed and developed rationally through scientific justification in the nanocrystal formulation along with quality by design paradigm. Box-Behnken design was applied to determine the optimized formulation based on the particle size and distribution, drug loading, zeta potential, and supersaturation parameters. The nanocrystal was formed through evaporation of drug, polymer, and surfactant in the solvent incorporated into mesoporous material. The nanocrystal was evaluated by vibrational spectroscopy, thermal analyses, and SEM and TEM photographs, followed by crystallinity evaluation. The results indicated that the factors only affected the particle size variation, zeta potential, drug loading, and the time to reach the supersaturation peak level. The optimized formulation was achieved by 68 % desirability value, producing 133.3 ± 1.2 nm particle size and -24.6 mV zeta potential. The physical and chemical evaluation characterization indicated no interaction between RSV and carrier. In addition, there was no difference in crystallinity between the RSV nanocrystal and native RSV. Moreover, the RSV nanocrystal improved the bioavailability nearly twice compared to the RSV suspension.

Glucuronide metabolites of trans-ε-viniferin decrease triglycerides accumulation in an in vitro model of hepatic steatosis

Trans-ε-viniferin, a resveratrol dimer found mainly in grapevine wood, has shown protective capacities against hepatic steatosis in vivo. Nevertheless, this compound is very poorly bioavailable. Thus, the aim of the present study is to determine the potential anti-steatotic properties of 1 and 10 µM of trans-ε-viniferin and its four glucuronide metabolites in AML-12 cells treated with palmitic acid as an in vitro model of hepatic steatosis. The effect of the molecules in cell viability and triglyceride accumulation, and the underlying mechanisms of action by Real-Time PCR and Western Blot were analysed, as well as the quantification of trans-ε-viniferin and the identified bioactive metabolite inside cells and their incubation media. Interestingly, we were able to determine the triglyceride-lowering property of one of the glucuronides (trans-ε-viniferin-2-glucuronide), which acts on de novo lipogenesis, fatty acid uptake and triglyceride assembly. The glucuronides of trans-ε-viniferin would therefore be partly responsible for the in vivo observed anti-steatotic properties of the parent compound.

Enhancing Solubility and Bioefficacy of Stilbenes by Liposomal Encapsulation-The Case of Macasiamenene F

Stilbenes in food and medicinal plants have been described as potent antiphlogistic and antioxidant compounds, and therefore, they present an interesting potential for the development of dietary supplements. Among them, macasiamenene F (MF) has recently been shown to be an effective anti-inflammatory and cytoprotective agent that dampens peripheral and CNS inflammation in vitro. Nevertheless, this promising molecule, like other stilbenes and a large percentage of drugs under development, faces poor water solubility, which results in trickier in vivo administration and low bioavailability. With the aim of improving MF solubility and developing a form optimized for in vivo administration, eight types of conventional liposomal nanocarriers and one type of PEGylated liposomes were formulated and characterized. In order to select the appropriate form of MF encapsulation, the safety of MF liposomal formulations was evaluated on THP-1 and THP-1-XBlue-MD2-CD14 monocytes, BV-2 microglia, and primary cortical neurons in culture. Furthermore, the cellular uptake of liposomes and the effect of encapsulation on MF anti-inflammatory effectiveness were evaluated on THP-1-XBlue-MD2-CD14 monocytes and BV-2 microglia. MF (5 mol %) encapsulated in PEGylated liposomes with an average size of 160 nm and polydispersity index of 0.122 was stable, safe, and the most promising form of MF encapsulation keeping its cytoprotective and anti-inflammatory properties.

Grapevine woody tissues accumulate stilbenoids following bud burst

MAIN CONCLUSION

After bud burst, a transcriptional reprogramming of the shikimate and phenylpropanoid pathways occurs in grapevine canes resulting in the accumulation of stilbenoids like resveratrol and viniferin. Stilbenoids are phenylpropanoid compounds with important biological properties and biotechnological applications that are synthesized in grapevine in response to different stresses. Although they are found in woody tissues, such as canes and buds, their biosynthesis and accumulation have been essentially described in berries. We have previously shown that transcripts encoding secondary metabolism enzymes accumulate in grapevine canes following the transition from dormancy (E-L 1) to bud burst (E-L 4) suggesting that secondary metabolites may accumulate in grapevine canes during this transition. In the present study, using UPLC-MS we demonstrate the accumulation of important metabolites such as ferulic acid and the stilbenoids E-resveratrol, E-piceatannol and E-ε-viniferin. Stilbenoids accumulation correlated with the increased expression of several stilbene synthase genes and of VviMYB14, encoding a transcription factor that regulates stilbene biosynthesis. In addition, a general stimulation of the plastidial shikimate pathway was observed. Taken together, results show that important secondary metabolites accumulate in the woody canes during bud burst. These findings may aid biotechnological approaches aimed at extracting biologically active phenolic compounds, including stilbenoids, from grapevine woody tissues.

Resveratrol, ε-Viniferin, and Vitisin B from Vine: Comparison of Their In Vitro Antioxidant Activities and Study of Their Interactions

The control of oxidative stress with natural active substances could limit the development of numerous pathologies. Our objective was to study the antiradical effects of resveratrol (RSV), ε-viniferin (VNF), and vitisin B (VB) alone or in combination, and those of a standardized stilbene-enriched vine extract (SSVE). In the DPPH-, FRAP-, and NO-scavenging assays, RSV presented the highest activity with an IC50 of 81.92 ± 9.17, 13.36 ± 0.91, and 200.68 ± 15.40 µM, respectively. All binary combinations resulted in additive interactions in the DPPH- and NO-scavenging assays. In the FRAP assay, a synergic interaction for RSV + VNF, an additive for VNF + VB, and an antagonistic for RSV + VB were observed. The ternary combination of RSV + VNF + VB elicited an additive interaction in the DPPH assay and a synergic interaction in the FRAP- and NO-scavenging assays. There was no significant difference between the antioxidant activity of the SSVE and that of the combination of RSV + VNF. In conclusion, RSV presented the highest effects, followed by VNF and VB. The interactions revealed additive or synergistic effects, depending on the combination of the stilbenes and assay.

The cancer preventive activity and mechanisms of prenylated resveratrol and derivatives

Resveratrol is regarded as neutraceuticals with multiple health benefits. The introduction of prenyl can enhance the bioactivity. In this work, the cancer preventive activities and mechanisms of 18 prenylated reseveratrol and derivatives were investigated. The results showed that prenyl increased the antiproliferative activities of resveratrol, oxyresveratrol and piceatannol against cancer cells, and their antiproliferative activities were time- and dose-dependent. 4-C-prenylation was important for the antiproliferative activity of stilbenoids. The 4-C-prenyl stilbenoids showed better antiproliferative activities than other prenylated stilbenoids. 4-C-prenyl piceatannol showed the best antiproliferative activity. Human hepatoellular carcinomas (HepG₂) cell was more sensitive to prenylated stilbenoids than human MCF-7 breast carcinoma cell. 4-C-prenyl piceatannol had high affinities to Caspase-3, Caspase-9, CDK2 and Cyclin A2. The possible amino acids involved in binding 4-C-prenyl piceatannol were revealed. The expression of Caspase-3 and Caspase-9 were upregulated by 4-C-prenyl piceatannol and the expression of CDK2 and Cyclin A2 in HepG₂ cells were downregulated, which contributed to apoptosis. The above results eludicated the possible antiproliferative mechanisms of prenylated stilbenoids.

Stilbenes, a Versatile Class of Natural Metabolites for Inflammation-An Overview

Stilbenes are polyphenolic allelochemicals synthesized by plants, especially grapes, peanuts, rhubarb, berries, etc., to defend themselves under stressful conditions. They are now exploited in medicine for their antioxidant, anti-proliferative and anti-inflammatory properties. Inflammation is the immune system's response to invading bacteria, toxic chemicals or even nutrient-deprived conditions. It is characterized by the release of cytokines which can wreak havoc on healthy tissues, worsening the disease condition. Stilbenes modulate NF-κB, MAPK and JAK/STAT pathways, and reduce the transcription of inflammatory factors which result in maintenance of homeostatic conditions. Resveratrol, the most studied stilbene, lowers the Michaelis constant of SIRT1, and occupies the substrate binding pocket. Gigantol interferes with the complement system. Besides these, oxyresveratrol, pterostilbene, polydatin, viniferins, etc., are front runners as drug candidates due to their diverse effects from different functional groups that affect bioavailability and molecular interactions. However, they each have different thresholds for toxicity to various cells of the human body, and thus a careful review of their properties must be conducted. In animal models of autoinflammatory diseases, the mode of application of stilbenes is important to their absorption and curative effects, as seen with topical and microemulsion gel methods. This review covers the diversity seen among stilbenes in the plant kingdom and their mechanism of action on the different inflammatory pathways. In detail, macrophages' contribution to inflamed conditions in the liver, the cardiac, connective and neural tissues, in the nephrons, intestine, lungs and in myriad other body cells is explored, along with detailed explanation on how stilbenes alleviate the symptoms specific to body site. A section on the bioavailability of stilbenes is included for understanding the limitations of the natural compounds as directly used drugs due to their rapid metabolism. Current delivery mechanisms include sulphonamides, or using specially designed synthetic drugs. It is hoped that further research may be fueled by this comprehensive work that makes a compelling argument for the exploitation of these compounds in medicine.

Benefits of skin application of piceatannol-A minireview

The skin is the largest organ of the human body and has several functions such as barrier against external agents, the maintenance of temperature and homeostatic functions. Skin ageing is a natural process that can be influenced by environmental factors, intrinsic skin factors and lifestyle. UV light plays an important role in skin ageing and can cause spots, requiring the use of depigmenting agents. Nowadays, there is a great demand for ingredients that prevent skin ageing, with natural agents occupying a promising position. Among the natural agents, polyphenols, such as resveratrol and piceatannol, found in grapes, passion fruits and other fruits, have a huge relevance. Great benefits of piceatannol have been reported, so thus, this work focuses specifically on a review of the literature regarding the application of this polyphenol in skin care products. This polyphenol can be used in a wound-healing, or as anti-ageing, antioxidant, anti-acne and skin whitening, among other effects.

The Wine Industry By-Products: Applications for Food Industry and Health Benefits

Each year, 20 million tons of wine by-products are generated, corresponding to 30% of the total quantity of vinified grapes. Wine by-products are a source of healthy bioactive molecules, such as polyphenols and other molecules (pigments, fibers, minerals, etc.). The abundance of bioactive compounds assures a promising future for nutritional foodstuff production. Wine by-products can be used to fortify aromatized waters and infusions, bread, pasta, dairy products, alcohol, sugary beverages, and processed foods. These innovative products are part of the Mediterranean diet and are of great interest to both human and environmental health. Pre-clinical studies show that consumption of food produced with wine by-products or with their extracts attenuates the inflammatory state and increases antioxidant status. As such, wine by-products provide protective effects against the underlying pathophysiological hallmarks of some chronic diseases such as atherosclerosis, diabetes, hypertension, obesity, and cancer. However, the poor bioavailability warrants further investigation on how to optimize the efficacy of wine by-products, and more clinical trials are also needed. The scientific evidence has validated the uses of the dietary nature of wine by-products and has helped to promote their use as a functional food to prevent chronic human diseases.

Identifying Major Drivers of Antioxidant Activities in Complex Polyphenol Mixtures from Grape Canes

Grape canes represent a valuable source of numerous polyphenols with antioxidant properties, whose compositions vary depending on the genotype and environmental factors. Antioxidant activities of pure molecules are often reported without considering possible interactions that may occur in complex polyphenol mixture. Using UPLC-MS-based metabolomics and unsupervised classification, we explored the polyphenol variations in grape cane extracts from a collection of European varieties. Antioxidant activities were assessed using ORAC, ABTS, DPPH, FRAP, CUPRAC and chelation assays. Pairwise correlations between polyphenols and antioxidant capacities were performed to identify molecules that contributed more to the antioxidant capacities within a complex mixture of polyphenols.

Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Stilbenes are some of the important phenolic compounds originating from plant families like Vitaceae, Leguminaceae, Gnetaceae, and Dipterocarpaceae. Structurally, they have a C6-C2-C6 skeleton, usually with two isomeric forms. Stilbenes are biosynthesized due to biotic and abiotic stresses such as microbial infections, high temperatures, and oxidation. This review aims to provide a comprehensive overview of stilbenes' botanical sources, chemistry, biosynthetic pathways, pharmacology, and clinical applications and challenges based on up-to-date data. All included studies were collected from PubMed, ScienceDirect, Google Scholar, and CNKI, and the presented data from these indexed studies were analyzed and summarized. A total of 459 natural stilbene compounds from 45 plant families and 196 plant species were identified. Pharmacological studies also show that stilbenes have various activities such as anticancer, antimicrobial, antioxidant, anti-inflammatory, anti-degenerative diseases, anti-diabetic, neuroprotective, anti-aging, and cardioprotective effects. Stilbene synthase (STS) is the key enzyme involved in stilbene biosynthetic pathways. Studies on the therapeutic application of stilbenes pinpoint that challenges such as low bioavailability and isomerization are the major bottlenecks for their development as therapeutic drugs. Although the medicinal uses of several stilbenes have been demonstrated in vivo and in vitro, studies on the development of stilbenes deserve more attention in the future.

Grapevine Wastes: A Rich Source of Antioxidants and Other Biologically Active Compounds

Wine production is one of the most critical agro-industrial sectors worldwide, generating large amounts of waste with negative environmental impacts, but also with high economic value and several potential applications. From wine shoots to grape pomace or seeds, all of the wastes are rich sources of bioactive compounds with beneficial effects for human health, with these compounds being raw materials for other industries such as the pharmaceutical, cosmetic or food industries. Furthermore, these compounds present health benefits such as being antioxidants, supporting the immune system, anti-tumoral, or preventing cardiovascular and neural diseases. The present work aims to be a critical discussion of the extraction methods used for bioactive compounds from grapevine waste and their beneficial effects on human health.

Trans-ε-Viniferin Encapsulation in Multi-Lamellar Liposomes: Consequences on Pharmacokinetic Parameters, Biodistribution and Glucuronide Formation in Rats

Trans-ε-viniferin (εVin) is a resveratrol dimer exhibiting promising biological activities for human health. Its bioavailability being low, the development of encapsulation methods would be used to overcome this issue. The aim of this study was to measure the consequences of the encapsulation of εVin in multilamellar liposomes on its pharmacokinetic parameters, metabolism and tissue distribution in rats. After oral administration of εVin (20 mg/kg body weight), either as free or encapsulated forms, plasmas were sequentially collected (from 0 to 4 h) as well as liver, kidneys and adipose tissues (4 h after administration) and analyzed by LC-HRMS. The glucuronide metabolites (εVG) were also produced by hemisynthesis for their quantification in plasma and tissues. The encapsulation process did not significantly modify the pharmacokinetic parameters of εVin itself. However, a significant increase of the T1/2 was noticed for εVG after administration of the encapsulated form as compared to the free form. An accumulation of εVin and εVG in adipose tissues was noticed, and interestingly a significant increase of the latter in the mesenteric one after administration of the encapsulated form was highlighted. Since adipose tissues could represent storage depots, and encapsulation allows for prolonging the exposure time of glucuronide metabolites in the organism, this could be of interest to promote their potential biological activities.

Encapsulation of phenolic compounds within food-grade carriers and delivery systems by pH-driven method: a systematic review

In comparison to conventional encapsulation methods of phenolic compounds (PCs), pH-driven method is green, simple and requires low energy consumption. It has a huge potential for industrial applications, and can overcome more effectively the aqueous solubility, stability and bioavailability issues related to PCs by changing pH to induce the encapsulation of PCs. This review aims to shed light on the use of pH-driven method for encapsulating PCs. The preparation steps and principles governing pH-driven method using various carriers and delivery systems are provided. A comparison of pH-driven with other methods is also presented. To circumvent the drawbacks of pH-driven method, improvement strategies are proposed. The essence of pH-driven method relies simultaneously on alkalization and acidification to bind PCs and carriers. It is used for the development of nanoemulsions, liposomes, edible films, nanoparticles, nanogels and functional foods. As a result of pH-driven method, PCs-loaded carriers may have smaller size, high encapsulation efficiency, more sustained-release and good bioavailability, due mainly to effects of pH change on the structure and properties of PCs as well as carriers. Finally, modification of wall materials and type of acidifier are considered as efficient approaches to improve the pH-driven method.

Recovery of Polyphenols from Vineyard Pruning Wastes-Shoots and Cane of Hybrid Grapevine (Vitis sp.) Cultivars

Grapevine shoots and canes represent a significant amount of biomass, considered as a waste in viticulture. In cooler climates, grapevines are pruned in the autumn (October) and spring (March) due to harsh winter conditions (e.g., snow, low temperatures), and large amounts of biomass are produced at these different pruning times. This work was undertaken in order to investigate the potential of vineyard pruning waste for recovery of polyphenolic compounds for biomass valorization. Qualitative and quantitative analyses of grapevine shoot and cane polyphenols, including flavonoids and stilbenoids were performed using UHPLC MS/MS method. The results revealed the flavonols (quercetin) to be the most abundant compounds in shoots among all the three cultivars screened (Zilga, Hasansky Sladky, Rondo). Stilbenoids (ε-viniferin) dominated in the canes, while increased level of flavonols with lower contents of stilbenoids was detected in the endo-dormant canes, and higher amounts of flavanols and stilbenoids were recorded in eco-dormant canes. In conclusion, the content of polyphenols in grapevine shoots and canes differed among the cultivars and dormancy phases. The results generated from the present study contribute to the sustainable and environmentally friendly viticulture practice via valorization of vineyard pruning wastes.

Activity Guided Isolation of Phenolic Compositions from Anneslea fragrans Wall. and Their Cytoprotective Effect against Hydrogen Peroxide Induced Oxidative Stress in HepG2 Cells

Anneslea fragrans Wall., commonly known as “Pangpo Tea”, is traditionally used as a folk medicine and healthy tea for the treatment of liver and intestine diseases. The aim of this study was to purify the antioxidative and cytoprotective polyphenols from A. fragrans leaves. After fractionation with polar and nonpolar organic solvents, the fractions of aqueous ethanol extract were evaluated for their total phenolic (TPC) and flavonoid contents (TFC) and antioxidant activities (DPPH, ABTS, and FRAP assays). The n-butanol fraction (BF) showed the highest TPC and TFC with the strongest antioxidant activity. The bio-guided chromatography of BF led to the purification of six flavonoids (1–6) and one benzoquinolethanoid (7). The structures of these compounds were determined by NMR and MS techniques. Compound 6 had the strongest antioxidant capacity, which was followed by 5 and 2. The protective effect of the isolated compounds on hydrogen peroxide (H₂O₂)-induced oxidative stress in HepG2 cells revealed that the compounds 5 and 6 exhibited better protective effects by inhibiting ROS productions, having no significant difference with vitamin C (p > 0.05), whereas 6 showed the best anti-apoptosis activity. The results suggest that A. fragrans could serve as a valuable antioxidant phytochemical source for developing functional food and health nutraceutical products.

Central Administration of Ampelopsin A Isolated from Vitis vinifera Ameliorates Cognitive and Memory Function in a Scopolamine-Induced Dementia Model

Neurodegenerative diseases are characterized by the progressive degeneration of the function of the central nervous system or peripheral nervous system and the decline of cognition and memory abilities. The dysfunctions of the cognitive and memory battery are closely related to inhibitions of neurotrophic factor (BDNF) and brain-derived cAMP response element-binding protein (CREB) to associate with the cholinergic system and long-term potentiation. Vitis vinifera, the common grapevine, is viewed as the important dietary source of stilbenoids, particularly the widely-studied monomeric resveratrol to be used as a natural compound with wide-ranging therapeutic benefits on neurodegenerative diseases. Here we found that ampelopsin A is a major compound in V. vinifera and it has neuroprotective effects on experimental animals. Bath application of ampelopsin A (10 ng/µL) restores the long-term potentiation (LTP) impairment induced by scopolamine (100 μM) in hippocampal CA3-CA1 synapses. Based on these results, we administered the ampelopsin A (10 ng/µL, three times a week) into the third ventricle of the brain in C57BL/6 mice for a month. Chronic administration of ampelopsin A into the brain ameliorated cognitive memory-behaviors in mice given scopolamine (0.8 mg/kg, i.p.). Studies of mice’s hippocampi showed that the response of ampelopsin A was responsible for the restoration of the cholinergic deficits and molecular signal cascades via BDNF/CREB pathways. In conclusion, the central administration of ampelopsin A contributes to increasing neurocognitive and neuroprotective effects on intrinsic neuronal excitability and behaviors, partly through elevated BDNF/CREB-related signaling.

Encapsulation of ε-Viniferin into Multi-Lamellar Liposomes: Development of a Rapid, Easy and Cost-Efficient Separation Method to Determine the Encapsulation Efficiency

Onion-type multi-lamellar liposomes (MLLs), composed of a mixture of phosphatidylcholine and Tween 80, were analyzed for their ability to encapsulate ε-Viniferin (εVin), a resveratrol dimer. Their encapsulation efficiency (EE) was measured by UV-VIS spectroscopy using three different separation methods—ultracentrifugation, size exclusion chromatography, and a more original and advantageous one, based on adsorption filtration. The adsorption filtration method consists indeed of using syringe filters to retain the molecule of interest, and not the liposomes as usually performed. The process is rapid (less than 10 min), easy to handle, and inexpensive in terms of sample amount (around 2 mg of liposomes) and equipment (one syringe filter is required). Whatever the separation method, a similar EE value was determined, validating the proposed method. A total of 80% ± 4% of εVin was found to be encapsulated leading to a 6.1% payload, roughly twice those reported for resveratrol-loaded liposomes. Finally, the release kinetics of εVin from MLLs was followed for a 77 day period, demonstrating a slow release of the polyphenol.

Palladium-Catalyzed Three-Component Carbocarbonation of Arynes: Expeditious Synthesis of o-Alkylated Arylacrylates and Stilbenes

A palladium-catalyzed multicomponent reaction involving olefin-tethered aryl iodides, arynes, and electrophilic alkenes has been developed for straightforward synthesis of o-alkylated arylacrylates and stilbenes through tandem intramolecular Heck cyclization/aryne dicarbofunctionalization.

Biotic and Abiotic Elicitors of Stilbenes Production in Vitis vinifera L. Cell Culture

The in vitro cell cultures derived from the grapevine (Vitis vinifera L.) have been used for the production of stilbenes treated with different biotic and abiotic elicitors. The red-grape cultivar Váh has been elicited by natural cellulose from Trichoderma viride, the cell wall homogenate from Fusarium oxysporum and synthetic jasmonates. The sodium-orthovanadate, known as an inhibitor of hypersensitive necrotic response in treated plant cells able to enhance production and release of secondary metabolite into the cultivation medium, was used as an abiotic elicitor. Growth of cells and the content of phenolic compounds trans-resveratrol, trans-piceid, δ-viniferin, and ɛ-viniferin, were analyzed in grapevine cells treated by individual elicitors. The highest accumulation of analyzed individual stilbenes, except of trans-piceid has been observed after treatment with the cell wall homogenate from F. oxysporum. Maximum production of trans-resveratrol, δ- and ɛ-viniferins was triggered by treatment with cellulase from T. viride. The accumulation of trans-piceid in cell cultures elicited by this cellulase revealed exactly the opposite effect, with almost three times higher production of trans-resveratrol than that of trans-piceid. This study suggested that both used fungal elicitors can enhance production more effectively than commonly used jasmonates.

In Vivo Genotoxicity Evaluation of a Stilbene Extract Prior to Its Use as a Natural Additive: A Combination of the Micronucleus Test and the Comet Assay

Genotoxic data of substances that could be used as food additives are required by the European Food Safety Authority. In this sense, the use of an extract from grapevine shoots containing a stilbene richness of 99% (ST-99), due to its antioxidant and antibacterial activities, has been proposed as an alternative to sulfur dioxide in wine. The aim of this work was to study, for the first time, the in vivo genotoxic effects produced in rats orally exposed to 90, 180, or 360 mg ST-99/kg body weight at 0, 24, and 45 h. The combination of micronucleus assay in bone marrow (OECD 474) and standard (OECD 489) and enzyme-modified comet assay was used to determine the genotoxicity on cells isolated from stomach, liver, and blood of exposed animals. The ST-99 revealed no in vivo genotoxicity. These results were corroborated by analytical studies that confirm the presence of stilbenes and their metabolites in plasma and tissues. Moreover, to complete these findings, a histopathological study was performed under light microscopy in liver and stomach showing only slight modifications in both organs at the highest concentration used. The present work confirms that this extract is not genotoxic presenting a good profile for its potential application as a preservative in the wine industry.

Impact of Environmental Factors on Stilbene Biosynthesis

Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

Grape Berry Secondary Metabolites and Their Modulation by Abiotic Factors in a Climate Change Scenario-A Review

Temperature, water, solar radiation, and atmospheric CO₂ concentration are the main abiotic factors that are changing in the course of global warming. These abiotic factors govern the synthesis and degradation of primary (sugars, amino acids, organic acids, etc.) and secondary (phenolic and volatile flavor compounds and their precursors) metabolites directly, via the regulation of their biosynthetic pathways, or indirectly, via their effects on vine physiology and phenology. Several hundred secondary metabolites have been identified in the grape berry. Their biosynthesis and degradation have been characterized and have been shown to occur during different developmental stages of the berry. The understanding of how the different abiotic factors modulate secondary metabolism and thus berry quality is of crucial importance for breeders and growers to develop plant material and viticultural practices to maintain high-quality fruit and wine production in the context of global warming. Here, we review the main secondary metabolites of the grape berry, their biosynthesis, and how their accumulation and degradation is influenced by abiotic factors. The first part of the review provides an update on structure, biosynthesis, and degradation of phenolic compounds (flavonoids and non-flavonoids) and major aroma compounds (terpenes, thiols, methoxypyrazines, and C13 norisoprenoids). The second part gives an update on the influence of abiotic factors, such as water availability, temperature, radiation, and CO₂ concentration, on berry secondary metabolism. At the end of the paper, we raise some critical questions regarding intracluster berry heterogeneity and dilution effects and how the sampling strategy can impact the outcome of studies on the grapevine berry response to abiotic factors.

Characterization of Stilbene Composition in Grape Berries from Wild Vitis Species in Year-To-Year Harvest

Asian and American Vitis species possess a strong potential for crossbreeding programs, owing to their several resistance properties. Stilbenes are phenolic compounds present in grape berries and are well-known for their main role as phytoalexins and resistance to biotic stresses in plants. However, their identification and quantification in grape berries from wild Vitis remains unexplored. A mass spectrometry multiple reaction monitoring method combined with the analysis of pure standards allowed for the unambiguous characterization of 20 stilbenes in the grape berry skin extracts of nine native Vitis species and one cultivated Vitis vinifera species (cv. Cabernet Sauvignon). A main occurrence of monomeric (Z-piceid, E-piceid, E-isorhapontin, and E-astringin), dimeric (E-ε-viniferin, Z-ε-viniferin, and pallidol), and oligomeric (isohopeaphenol and r-viniferin) stilbenes was highlighted. Some stilbenes were clearly characterized for the first time in grape berries, such as the dimers ampelopsin A, E-vitisinol C, and parthenocissin A as well as the tetramers r2-viniferin and r-viniferin. Stilbene composition and content varied widely among several Vitis species and vintage years.

Polyphenol Profiles of Just Pruned Grapevine Canes from Wild Vitis Accessions and Vitis vinifera Cultivars

Grapevine canes are an abundant byproduct of the wine industry. The stilbene contents of Vitis vinifera cultivars have been largely studied, but little is known about the stilbene contents of wild Vitis accessions. Moreover, there have only been few studies on the quantification of other phenolic compounds in just pruned grapevine canes. In our study, we investigated the polyphenol profile of 51 genotypes belonging to 15 Vitis spp. A total of 36 polyphenols (20 stilbenes, 6 flavanols, 7 flavonols, and 3 phenolic acids) were analyzed by high-performance liquid chromatography coupled with a triple quadrupole mass spectrometer. Our results suggest that some wild Vitis accessions could be of interest in terms of the concentration of bioactive polyphenols and that flavanols contribute significantly to the antioxidant activity of grapevine cane extracts. To the best of our knowledge, this is the most exhaustive study of the polyphenolic composition of grapevine canes of wild Vitis spp.

Cytotoxicity studies of a stilbene extract and its main components intended to be used as preservative in the wine industry

The use of stilbenes has been proposed as an alternative to sulfur dioxide in wine. Provided the feasibility from a technological approach, the cytotoxicity of an extract from grapevine shoots containing a stilbene richness of 99% (ST-99 extract) was assessed in the human cell lines HepG2 and Caco-2. In addition, the effects of the main stilbenes found in ST-99, trans-resveratrol and trans-ε-viniferin were studied, as well as its mixture. Similar cytotoxic effects were obtained in the exposures to trans-ε-viniferin, ST-99 and the mixture; however, trans-resveratrol alone exerted less toxicity. When HepG2 cells were exposed to trans-ε-viniferin, ST-99 and the mixture, the mean effective concentration (EC₅₀) were 28.28 ± 2.15, 31.91 ± 1.55 and 29.47 ± 3.54 µg/mL, respectively. However, in the exposure to trans-resveratrol, the EC₅₀ was higher 50 µg/mL. The morphological study evidenced damage at ultrastructural level in HepG2 cells, highlighting the inhibition of cell proliferation and the induction of apoptosis. The type of interaction produced by trans-ε-viniferin and trans-resveratrol mixtures was assessed by an isobologram analysis using the CalcuSyn software, evidencing an antagonist effect. These data comprise a starting point in the toxicological assessment; further studies are needed in this field to assure the safety of the extract ST-99.

Grapevine Cane Extracts: Raw Plant Material, Extraction Methods, Quantification, and Applications

Grapevine canes are viticulture waste that is usually discarded without any further use. However, recent studies have shown that they contain significant concentrations of health-promoting compounds, such as stilbenes, secondary metabolites of plants produced as a response to biotic and abiotic stress from fungal disease or dryness. Stilbenes have been associated with antioxidant, anti-inflammatory, and anti-microbial properties and they have been tested as potential treatments of cardiovascular and neurological diseases, and even cancer, with promising results. Stilbenes have been described in the different genus of the Vitaceae family, the Vitis genera being one of the most widely studied due to its important applications and economic impact around the world. This review presents an in-depth study of the composition and concentration of stilbenes in grapevine canes. The results show that the concentration of stilbenes in grapevine canes is highly influenced by the Vitis genus and cultivar aspects (growing conditions, ultraviolet radiation, fungal attack, etc.). Different methods for extracting stilbenes from grapevine canes have been reviewed, and the extraction conditions have also been studied, underlining the advantages and disadvantages of each technique. After the stilbenes were extracted, they were analyzed to determine the stilbene composition and concentration. Analytical techniques have been employed with this aim, in most cases using liquid chromatography, coupled with others such as mass spectrometry and/or nuclear magnetic resonance to achieve the individual quantification. Finally, stilbene extracts may be applied in multiple fields based on their properties. The five most relevant are preservative, antifungal, insecticide, and biostimulant applications. The current state-of-the-art of the above applications and their prospects are discussed.

Metabolomic analysis of Cyrtopodium glutiniferum extract by UHPLC-MS/MS and in vitro antiproliferative and genotoxicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of orchids have been traditionally used as human phytotherapeutics. Cyrtopodium flavum, for example, due to the analgesic and anti-inflammatory properties, beside the capacity of heal skin lesions has been focus of research. Also Cyrtopodium glutiniferum, an orchid found in the Brazilian southeastern rainforest, is known to synthesize anti-inflammatory glucomannans in the pseudobulbs, as other potentially therapeutic compounds.

AIM OF THE STUDY

We have reported the first metabolomic analysis focused on the phenols expression of the neotropical orchid Cyrtopodium glutiniferum Raddi, besides free radical scavenging, anti-inflammatory and antiproliferative activities, and the genotoxicity properties of the aqueous extract.

MATERIAL AND METHODS

The metabolomics of C. glutiniferum aqueous extract was performed through UHPLC-MSⁿ acquisition. We have detected the scavenging potential of the extract using DPPH assay. The genotoxic potential was performed by Ames Test (0-5000 μg mL^-1) and micronucleous assay (0-5000 μg mL^-1) in RAW264.7 cells. The cytotoxic potential of the extract against RAW264.7 was tested by WST-1 assay (0-500 μg mL^-1). And after all, the RAW264.7 cells were treated with non-cytotoxic concentrations of C. glutiniferum (0-50 μg mL^-1) to evaluate the antiproliferative and anti-inflammatory potential, besides the mitochondrial activity.

RESULTS

From the 55 molecules identified, 45.5% belonged to the phenolic compounds database from Phenol Explorer, 29% to an in-house Orchidaceae molecules database, and 25.5% to both. Among the identified phenolic compounds, 18 subclasses were discriminated, being phenanthrenes the most abundant. Doses-dependent of C. glutiniferum extracts were able to induce DPPH free radicals scavenging and also to increase TA100 His⁺ revertants, in metabolic environment, showing mutagenicity just in the highest concentration, of 5 mg/plate. On Eukaryotic cell models, the extract also has induced dose-response and time-response cytotoxicity against RAW264.7 macrophages, mainly after 48 h and 72 h, even though the extract has not been able to induce the increase of micronucleated cells and mitotic index alteration on Micronucleus assay. The activation and proliferation of macrophages cultures were downregulated after 24 h and 48 h by the non-cytotoxic concentrations of the extract in a dose-dependent manner.

CONCLUSIONS

The Cyrtopodium glutiniferum metabolomics, anti-inflammatory and anti-proliferative properties observed in this study suggest a therapeutic efficacy of the orchid extract applied in folk medicine.

A Reference List of Phenolic Compounds (Including Stilbenes) in Grapevine (Vitis vinifera L.) Roots, Woods, Canes, Stems, and Leaves

Due to their biological activities, both in plants and in humans, there is a great interest in finding natural sources of phenolic compounds or ways to artificially manipulate their levels. During the last decade, a significant amount of these compounds has been reported in the vegetative organs of the vine plant. In the roots, woods, canes, stems, and leaves, at least 183 phenolic compounds have been identified, including 78 stilbenes (23 monomers, 30 dimers, 8 trimers, 16 tetramers, and 1 hexamer), 15 hydroxycinnamic acids, 9 hydroxybenzoic acids, 17 flavan-3-ols (of which 9 are proanthocyanidins), 14 anthocyanins, 8 flavanones, 35 flavonols, 2 flavones, and 5 coumarins. There is great variability in the distribution of these chemicals along the vine plant, with leaves and stems/canes having flavonols (83.43% of total phenolic levels) and flavan-3-ols (61.63%) as their main compounds, respectively. In light of the pattern described from the same organs, quercetin-3-O-glucuronide, quercetin-3-O-galactoside, quercetin-3-O-glucoside, and caftaric acid are the main flavonols and hydroxycinnamic acids in the leaves; the most commonly represented flavan-3-ols and flavonols in the stems and canes are catechin, epicatechin, procyanidin B1, and quercetin-3-O-galactoside. The main stilbenes (trans-ε-viniferin, trans-resveratrol, isohopeaphenol/hopeaphenol, vitisin B, and ampelopsins) accumulate primarily in the woods, followed by the roots, the canes, and the stems, whereas the leaves, which are more exposed to environmental stresses, have a low concentration of these compounds. Data provided in this review could be used as (i) a metabolomic tool for screening in targeted and untargeted analyses and (ii) a reference list in studies aimed at finding ways to induce naturally occurring polyphenols on an industrial scale for pant and human disease control.

Resveratrol transformation in red wine after heat treatment

Resveratrol is a well-known wine constituent. Its concentration can vary according to the cultivar choice and the winemaking process. Due to its phenolic structure, resveratrol could be transformed under high temperature or oxidative conditions, leading to the formation of various derivatives including oligomers. Hence, the goal of this study is to investigate the presence of these derivatives in wine. In the first stage, hemisynthesis of oligomeric stilbenes was achieved from resveratrol in ethanol by oxidative coupling using metals. Four de novo synthetized resveratrol derivatives were identified by MS and NMR spectroscopy including two new molecules, oxistilbenin F and oxistilbenin G. In the second stage, analysis of red wine after heat treatment by LC-MS confirmed the presence of some of these compounds in wine. Finally, the anti-inflammatory effects of the compounds were evaluated by studying their ability to prevent lipopolysaccharide (LPS)-induced upregulation of nitric oxide (NO) and reactive oxygen species (ROS) production in RAW 264.7 macrophage cell line.

Identification and Quantification of Stilbenes (Piceatannol and Resveratrol) in Passiflora edulis By-Products

Recently, studies on the by-products from the food industry, such as passion fruit seeds, have significantly increased, as these can have an added value, due to their properties, such as potential antioxidant activity. This study was conducted to determine the presence of piceatannol and resveratrol in various extracts of passion fruit (Passiflora edulis) seeds from Madeira Island and a commercial passion fruit oil was used as reference. The commercial oil and the extracts that were obtained by traditional Soxhlet method with ethanol and acetone did not reveal the presence of the two stilbenes, piceatannol and resveratrol. However, the extracts that were obtained by the ultrasound method showed significant amounts of piceatannol and resveratrol when compared with the commercial oil. The presence of these compounds indicates that this oil could have potential application in cosmetic and pharmaceutical industries, due to their proven antioxidant and anti-aging properties.

Encapsulation of ε-viniferin in onion-type multi-lamellar liposomes increases its solubility and its photo-stability and decreases its cytotoxicity on Caco-2 intestinal cells

ε-Viniferin, a resveratrol dimer, is a naturally occurring stilbene that has been studied so far for its potential beneficial effects on human health. Its low water solubility, its photo-sensitivity and its low bioavailability make its applications in the food industry complicated. To overcome these limitations, ε-viniferin was encapsulated in phospholipid-based multi-lamellar liposomes (MLLs) called spherulites or onions. In the best case, an encapsulation efficiency of 58 ± 3% and a bioactive loading of 4.2 ± 0.5% were reached. Encapsulation of ε-viniferin drastically increased its water solubility by more than 5 orders to reach 17.4 g L-1 and provided protection against its UV-induced isomerization. While ε-viniferin was shown to be significantly toxic to Caco-2 intestinal-like cells for concentrations higher than 25 μM, once encapsulated in MLLs, those cells did not experience any mortality even for the highest tested stilbene concentration (100 μM) as revealed by red neutral assay.

Metabolite profiling during graft union formation reveals the reprogramming of primary metabolism and the induction of stilbene synthesis at the graft interface in grapevine

BACKGROUND

Grafting with rootstocks is essential for the culture of many perennial fruit crops and is increasing being used in the production of annual fruits and vegetables. Our previous work based on microarrays showed that transcripts encoding enzymes of both primary and secondary metabolism were differentially expressed during graft union formation in both homo-grafts (a genotype grafted with itself) and hetero-grafts (two different genotypes grafted together). The aim of this study was to profile primary and secondary metabolites, and quantify the activity of phenylalanine ammonia lyase (PAL) and neutral invertase (NI) in the scion and rootstock tissues and the graft interface of homo and hetero-grafts of grapevine 1 month after grafting. Table-top grafting was done on over-wintering stems (canes) of grapevine and the graft interface tissues (containing some woody stem tissues and callus) were compared to the surrounding rootstock and scion tissues. The objective was to identify compounds involved in graft union formation and hetero-grafting responses.

RESULTS

A total of 54 compounds from primary and secondary metabolism (19 amino acids, five primary and 30 secondary compounds metabolites) and the activity of two enzymes were measured. The graft interface was associated with an increase in the accumulation of the branched-chain amino acids, basic amino acids, certain stilbene compounds and higher PAL and NI activity in comparison to the surrounding woody stem tissues. Some amino acids and stilbenes were identified as being accumulated differently between the graft interfaces of the scion/rootstock combinations in a manner which was unrelated to their concentrations in the surrounding woody stem tissues.

CONCLUSIONS

This study revealed the modification of primary metabolism to support callus cell formation and the stimulation of stilbene synthesis at the graft interface, and how these processes are modified by hetero-grafting. Knowledge of the metabolites and/or enzymes required for successful graft union formation offer us the potential to identify markers that could be used by nurseries and researchers for selection and breeding purposes.

Piceatannol Increases Antioxidant Defense and Reduces Cell Death in Human Periodontal Ligament Fibroblast under Oxidative Stress

Piceatannol is a resveratrol metabolite that is considered a potent antioxidant and cytoprotector because of its high capacity to chelate/sequester reactive oxygen species. In pathogenesis of periodontal diseases, the imbalance of reactive oxygen species is closely related to the disorder in the cells and may cause changes in cellular metabolism and mitochondrial activity, which is implicated in oxidative stress status or even in cell death. In this way, this study aimed to evaluate piceatannol as cytoprotector in culture of human periodontal ligament fibroblasts through in vitro analyses of cell viability and oxidative stress parameters after oxidative stress induced as an injury simulator. Fibroblasts were seeded and divided into the following study groups: control, vehicle, control piceatannol, H2O2 exposure, and H2O2 exposure combined with the maintenance in piceatannol ranging from 0.1 to 20 μM. The parameters analyzed following exposure were cell viability by trypan blue exclusion test, general metabolism status by the 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method, mitochondrial activity through the ATP production, total antioxidant capacity, and reduced gluthatione. Piceatannol was shown to be cytoprotective due the maintenance of cell viability between 1 and 10 μM even in the presence of H2O2. In a concentration of 0.1 μM piceatannol decreased significantly cell viability but increased cellular metabolism and antioxidant capacity of the fibroblasts. On the other hand, the fibroblasts treated with piceatannol at 1 μM presented low metabolism and antioxidant capacity. However, piceatannol did not protect cells from mitochondrial damage as measured by ATP production. In summary, piceatannol is a potent antioxidant in low concentrations with cytoprotective capacity, but it does not prevent all damage caused by hydrogen peroxide.

In Vitro Toxicity Assessment of Stilbene Extract for Its Potential Use as Antioxidant in the Wine Industry

The reduction of sulfur dioxide in wine is a consumer's demand, considering the allergic effects that may occur in people who are sensitive to it. Stilbenes are candidates of great interest for this purpose because of their antioxidant/antimicrobial activities and health properties, and also because they are naturally found in the grapevine. In the present study, the in vitro toxicity of an extract from grapevine shoots (with a stilbene richness of 45.4%) was assessed in two human cell lines. Significant damage was observed from 30 μg/mL after 24 h, and 40 µg/mL after 48 h of exposure. Similarly, the ultrastructural study revealed a significant impairment of cell growing. The extract was able to protect cells against an induced oxidative stress at all concentrations studied. In view of the promising results, a more exhaustive toxicological assessment of the extract is needed to confirm the safety of its further use as additive in wine.

Impact of food polyphenols on oxylipin biosynthesis in human neutrophils

The intake of food polyphenols is associated with beneficial impacts on health. Besides anti-oxidative effects, anti-inflammatory properties have been suggested as molecular modes of action, which may result from modulations of the arachidonic acid (AA) cascade. Here, we investigated the effects of a library of food polyphenols on 5-lipoxygenase (5-LOX) activity in a cell-free assay, and in human neutrophils. Resveratrol, its dimer (ε-viniferin), and its imine analogue (IRA) potently blocked the 5-LOX-mediated LT formation in neutrophils with IC₅₀ values in low μM-range. Among the tested flavonoids only the isoflavone genistein showed potent 5-LOX inhibition in neutrophils (IC₅₀ = 0.4 ± 0.1 μM), however was ineffective on isolated 5-LOX. We exclude an interference with the 5-LOX-activating protein (FLAP) in HEK_5-LOX/±FLAP cells and suggest global effects on intact immune cells. Using LC-MS based targeted oxylipin metabolomics, we analyzed the effects of 5-LOX-inhibiting polyphenols on all branches of the AA cascade in Ca²⁺-ionophore-challenged neutrophils. While ε-viniferin causes a clear substrate shunt towards the remaining AA cascade enzymes (15-LOX, cyclooxygenase - COX-1/2, cytochrome P450), resveratrol inhibited the COX-1/2 pathway and showed a weak attenuation of 12/15-LOX activity. IRA had no impact on 15-LOX activity, but elevated the formation of COX-derived prostaglandins, having no inhibitory effects on COX-1/2. Overall, we show that food polyphenols have the ability to block 5-LOX activity and the oxylipin pattern is modulated with a remarkable compound/structural specificity. Taken the importance of polyphenols for a healthy diet and their concentration in food supplements into account, this finding justifies further investigation.

Inhibition of VEGFR-2 Phosphorylation and Effects on Downstream Signaling Pathways in Cultivated Human Endothelial Cells by Stilbenes from Vitis Spp

Stilbenes are phenolic compounds present in different higher plant families that have shown different biological activities, such as antioxidant properties and antitumoral and anti-atherosclerotic effects, among others. Angiogenesis is a key process involved in both cancer and cardiovascular diseases, the vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 being the main triggers. Certain polyphenol compounds, such as flavonoids, have shown a potent capacity to inhibit VEGF and, consequently, angiogenesis. The present work, therefore, aims to evaluate the potential effect of stilbenes on inhibiting VEGF and their subsequent effect on the downstream signaling pathway (PLCγ1, Akt, and eNOS). VEGFR-2 activation was studied through an ELISA assay in the HUVEC line, while the phosphorylation of intracellular downstream proteins PLCγ1, Akt, and eNOS was tested by Western blot. Student's t test was used to determine significant differences between samples. On the one hand, astringin, pallidol, and ω-viniferin showed the lowest IC₅₀ values (2.90 ± 0.27, 4.42 ± 0.67, and 6.10 ± 1.29 μM, respectively) against VEGFR-2 activation. Additionally, VEGF-induced PLCγ1 phosphorylation was significantly inhibited by ε-viniferin, astringin, and ω-viniferin. However, ε-viniferin and pallidol simultaneously enhanced eNOS activation, proving to be via Akt activation in the case of ε-viniferin. For the first time, these data suggest that stilbenes such as astringin, pallidol, ω-viniferin, and ε-viniferin have a potential anti-angiogenic effect and they could be further considered as anti-VEGF ingredients in food and beverages. In addition, ε-viniferin and pallidol significantly allowed eNOS activation and could likely prevent the side effects caused by anti-VEGF hypertension drugs.

Theoretical studies on the antioxidant activity of viniferifuran

DFT studies reveal the thermodynamics and kinetics of radical scavenging reactions of a resveratrol dimer derivative – viniferifuran.

Tissular Distribution and Metabolism of trans-ε-Viniferin after Intraperitoneal Injection in Rat

Background: Recent studies showed that trans-ε-viniferin (ε-viniferin), a trans-resveratrol dehydrodimer, has anti-inflammatory and anti-obesity effects in rodents. The main purpose of this work was to assess the tissue distribution study of ε-viniferin and its metabolites after intraperitoneal (IP) administration in rat. Methods: After IP injection of 50 mg/kg, ε-viniferin and its metabolites were identified and quantified in plasma, liver, kidneys, adipose tissues, urine, and faeces by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). Results: ε-Viniferin underwent a rapid hepatic metabolism mostly to glucuronides but also to a lesser extent to sulphate derivatives. The highest glucuronide concentrations were found in liver followed by plasma and kidneys whereas only traces amounts were found in adipose tissues. In contrast the highest ε-viniferin areas under concentration (AUC) and mean residence times (MRT) values were found in white adipose tissues. Finally, much lower levels of ε-viniferin or its metabolites were found in urine than in faeces, suggesting that biliary excretion is the main elimination pathway. Conclusion: A rapid and large metabolism of ε-viniferin and a high bioaccumulation in white adipose tissues were observed. Thus, these tissues could be a reservoir of the native form of ε-viniferin that could allow its slow release and a sustained presence within the organism.

Fruits as Prospective Reserves of bioactive Compounds: A Review

Bioactive natural products have always played a significant role as novel therapeutical agents irrespective of their source of origin. They have a profound effect on human health by both direct and indirect means and also possess immense medicinal properties. Fruit species are largely appreciated and highly consumed throughout the world. Epidemiologic information supports the association between high intake of fruits and low risk of chronic diseases. There are several biological reasons why the consumption of fruits might reduce or prevent chronic diseases. Fruits are rich sources of nutrients and energy, have vitamins, minerals, fiber and numerous other classes of biologically active compounds. Moreover, parts of the fruit crops like fruit peels, leaves and barks also possess medicinal properties and have been included in this review. The most important activities discussed in this review include antidiabetic, anticancer, antihypertensive, neuroprotective, anti-inflammatory, antioxidant, antimicrobial, antiviral, stimulation of the immune system, cell detoxification, cholesterol synthesis, anticonvulsant and their ability to lower blood pressure. Several phytochemicals involved in this context are described with special emphasis on their structural properties and their relativity with human diseases.