Effect of drying methods on nutritional constitutes of fermented grape residue

One of the biggest hurdles faced by the wine industry is the disposal of residual biomass generated after vinification. Although this residue is biodegradable, it constitutes a potential source of environmental pollutants. To alleviate this issue, this biomass may be used in alternative applications; for example, it may be transformed into an enriched flour that can be used to improve the nutrient content in different foods. In this study, were evaluated the effects of drying processes on the relevant nutritional components in dry extracts obtained from the residue of fermented grape pomace. The concentrations of phenolic compounds and anthocyanins were higher when drying the flour by the traditional oven procedure than by freeze-drying. The highest difference (approximately 40%) was observed for tannin compounds. Therefore, drying in an oven is recommended due to the lower loss of bioactive compounds, in addition to being simple and cheap.

Effect of Natural Deep Eutectic Solvents on trans-Resveratrol Photo-Chemical Induced Isomerization and 2,4,6-Trihydroxyphenanthrene Electro-Cyclic Formation

trans-Resveratrol is a natural bioactive compound with well-recognized health promoting effects. When exposed to UV light, this compound can undergo a photochemically induced trans/cis isomerization and a 6π electrochemical cyclization with the subsequent formation of 2,4,6-trihydroxyphenanthrene (THP). THP is a potentially harmful compound which can exert genotoxic effects. In this work we improved the chromatographic separation and determination of the two resveratrol isomers and of THP by using a non-commercial pentafluorophenyl stationary phase. We assessed the effect of natural deep eutectic solvents (NaDES) as possible photo-protective agents by evaluating cis-resveratrol isomer and THP formation under different UV-light exposure conditions with the aim of enhancing resveratrol photostability and inhibiting THP production. Our results demonstrate a marked photoprotective effect exerted by glycerol-containing NaDES, and in particular by proline/glycerol NaDES, which exerts a strong inhibitory effect on the photochemical isomerization of resveratrol and significantly limits the formation of the toxic derivative THP. Considering the presence of resveratrol in various commercial products, these results are of note in view of the potential genotoxic risk associated with its photochemical degradation products and in view of the need for the development of green, eco-sustainable and biocompatible resveratrol photo-stable formulations.

Rapid, Highly-Sensitive and Ecologically Greener Reversed-Phase/Normal-Phase HPTLC Technique with Univariate Calibration for the Determination of Trans-Resveratrol

The rapid, highly-sensitive and ecologically greener reversed-phase (RP)/normal-phase (NP) high-performance thin-layer chromatography (HPTLC) densitometric technique has been developed and validated for the determination of trans-resveratrol (TRV). The reversed-phase HPTLC-based analysis of TRV was performed using ethanol–water (65:35, v v−1) combination as the greener mobile phase, while, the normal-phase HPTLC-based estimation of TRV was performed using chloroform–methanol (85:15, v v−1) combination as the routine mobile phase. The TRV detection was carried out at 302 nm for RP/NP densitometric assay. The linearity was recorded as 10–1200 and 30–400 ng band−1 for RP and NP HPTLC techniques, respectively. The RP densitometric assay was observed as highly-sensitive, accurate, precise and robust for TRV detection in comparison with the NP densitometric assay. The contents of TRV in commercial formulation were recorded as 101.21% utilizing the RP densitometric assay, while, the contents of TRV in commercial formulation were found to be 91.64% utilizing the NP densitometric assay. The greener profile of RP/NP technique was obtained using the analytical GREEnness (AGREE) approach. The AGREE scales for RP and NP densitometric assays were estimated 0.75 and 0.48, respectively. The recorded AGREE scale for the RP densitometric assay indicated that this technique was highly green/the ecologically greener compared to the NP densitometric assay. After successful optimization of analytical conditions, validation parameters, AGREE scale and chromatography performance, the RP densitometric assay with univariate calibration was found to be better than the NP densitometric assay for the analysis of TRV.

Resveratrol-enriched rice identical to original Dongjin rice variety with respect to major agronomic traits in different cultivation years and regions

Resveratrol is synthesized by the catalysis of resveratrol synthases (RS) in a limited number of higher plants. Resveratrol shows potential health-promoting properties, including as an antioxidant and in preventing cardiovascular diseases. Recently, resveratrol-enriched rice has been produced as a novel source of resveratrol. This study aimed to investigate the major agronomic characteristics of resveratrol-enriched rice, Iksan526 (I526) and compared them with those of a nontransgenic and commercial rice variety, Dongjin (DJ). Transgene (RS) integration was confirmed using Southern blot analysis, and homologous recombination was achieved after digestion with the SacI restriction enzyme. The phenotypic traits of I526 grown in Iksan were similar to those grown in Milyang but not similar to those grown in Suwon. In Suwon, I526 had slightly earlier heading dates [i.e., number of days from sowing to heading) and shorter culm lengths. When I526 was treated with 0.4% Basta in the seedling stage, no significant difference was observed among all the agronomic traits compared with nontreated I526; particularly, the culm length, panicle length, number of panicles per hill, 1,000 grain weight of brown rice, and brown rice yield of the Basta-treated rice were similar to those of the nontreated I526, regardless of their cultivation region. The resveratrol content of I526 grown in Suwon and Milyang was increased by 18% and 37%, respectively, than that of I526 grown in the Iksan area. Therefore, DJ and I526 are not significantly different in terms of major agronomic traits depending on variety/year and variety/cultivation region. The results indicated that I526 has the potential to become a commercialized variety in the near future.

Resveratrol: A Fair Race Towards Replacing Sulfites in Wines

In recent years, significant efforts to produce healthier wines has led to the replacement or reduction of the addition of sulfites, using alternative substances or techniques. Resveratrol and related biophenols seem to be of great interest, since beyond their protective nature and contrary to sulfites they can positively affect consumer health. These bioactive phytochemicals are naturally produced in grapes as evolutionary acquired mechanisms against pathogens and UV irradiation. However, despite the efforts made so far attempting to develop economic and industrially adopted isolation techniques, available quantities of these biophenols for commercial use are still quite limited. Therefore, such molecules are still not able to meet the needs of industrial use due to their prohibitive marketable cost. In this review we summarize the efforts that have been made to biosynthesize these molecules through alternative, innovative ways. Increasing interest in modern biotechnological approaches has shed light on the exploitation of metabolically engineered microbial factories, instead of plants, to produce molecules of industrial interest. Such approaches, also reviewed here, are expected to lower the cost and appear promising to produce enough surplus to attract further oenological experimentation upon yielding functional wines. This development is expected to attract further industrial attention, continuing the race to partially or totally replace the external addition of sulfites. We also review important physicochemical properties of resveratrol in relation to enriching wines.

Improvement of Resveratrol Effects When Combined with Rice Oil in Rat Models of Inflammation

This study investigated the effects of systemic treatment with a new formulation of resveratrol (RSV) vehicled in rice oil (RSVO) in experimental rat models of inflammation. Male Wistar rats were evaluated in the following in vivo models: carrageenan-induced acute edema, complete Freund's adjuvant (CFA)-evoked sub-chronic edema, and CFA-induced polyarthritis. The animals were treated orally with RSVO (10-15 mg/kg) or RSV (100-200 mg/kg), depending on the experimental protocol. RSV was more effective than RSVO in carrageenan-elicited acute edema when dosed in either prophylactic or therapeutic schemes of administration. However, the repeated RSVO administration, at 10-fold lower doses, exhibited superior anti-inflammatory actions in either the sub-chronic edema or the chronic polyarthritis model elicited by CFA, when compared with RSV. The novel formulation RSVO displayed a lower plasma biotransformation when compared with the RSV-treated group-46% versus 88% of metabolites, respectively. RSVO also prevented polyarthritis-related cartilage destruction, an effect that might rely on the inhibition of the pro-inflammatory cytokine interleukin-6 (IL-6), associated with an increase of the anti-inflammatory cytokine interleukin-10 (IL-10). Noteworthy, the long-term administration of RSVO did not elicit any gastrointestinal harm. Our study revealed that RSVO was notably effective in the long-term inflammatory and degenerative responses triggered by CFA. This innovative formulation might well represent a promising alternative for treating chronic inflammatory diseases, such as arthritis.

Development and in vitro assessment of psoralen and resveratrol co-loaded ultradeformable liposomes for the treatment of vitiligo

Vitiligo is a de-pigmenting skin disorder characterized by white patches on skin due to partial or complete loss of melanocytes. Psoralen in combination with ultraviolet-A (PUVA) acts by stimulation of melanin content and tyrosinase activity in melanocytes. Resveratrol, a sirtuin activator and a potential anti-oxidant reduce oxidative stress which is one of the triggering factors for initiation of vitiligo. Despite their therapeutic activity, weak percutaneous permeability of psoralen and poor solubility of resveratrol hinders their effective topical administration. The aim of present study is to formulate ultradeformable liposomes (UDL) co-loaded with psoralen and resveratrol for evaluation of PUVA and anti-oxidant combination in vitiligo treatment. For this purpose, UDL composed of DC-Chol, cholesterol and sodium deoxy cholate were prepared for their co-delivery. Liposomal carriers were characterized and evaluated for their efficacy using B16F10 cell line. Free radical scavenging potential was also determined for these carriers by in vitro anti-oxidant assays. Optimal co-loaded UDL with particle size ranging from 120 to 130nm, zeta potential of +46.2mV, entrapment efficiency of 74.09% (psoralen) and 76.91% (resveratrol) were obtained. Compared to control, co-loaded UDL showed significant stimulation of melanin and tyrosinase activity with major contribution of psoralen. Further, co-loaded UDL also exhibited potential free radical scavenging activity where resveratrol played a key role. Hence, psoralen and resveratrol co-loaded UDL acts in vitiligo through dual mechanisms of action viz., stimulation of melanin and tyrosinase activity as well as by anti-oxidant activity. These findings indicate that psoralen and resveratrol co-loaded UDL has the promising therapeutic potential for the treatment of vitiligo.

Resveratrol prevents akinesia and restores neuronal tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta of diabetic rats

This study evaluated the effects of resveratrol on locomotor behaviors, neuronal and glial densities, and tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta of rats with streptozotocin-induced diabetes. Animals were divided into four groups: non-diabetic rats treated with saline (SAL), non-diabetic rats treated with resveratrol (RSV), diabetic rats treated with saline (DM) and diabetic rats treated with resveratrol (DM+RSV). The animals received oral gavage with resveratrol (20 mg/kg) for 35 days. The open field test and the bar test were performed to evaluate bradykinesia and akinesia, respectively. The Nissl-stained neuronal and glial densities and the dopaminergic neuronal density were estimated using planar morphometry. Tyrosine hydroxylase immunoreactivity was evaluated using regional and cellular optical densitometry. In relation to the locomotor behaviors, it was observed that the DM group developed akinesia, which was attenuated by resveratrol in the DM+RSV group, while the DM and DM+RSV groups showed bradykinesia. Our main morpho-physiological results demonstrated: a decrease in the cellular tyrosine hydroxylase immunoreactivity in the DM group, which was attenuated by resveratrol in the DM+RSV group; a higher neuronal density in the RSV group, when compared to the DM and DM+RSV groups; an increase in the glial density in the DM group, which was also reversed by resveratrol in the DM+RSV group. Resveratrol treatment prevents akinesia development and restores neuronal tyrosine hydroxylase immunoreactivity and glial density in the substantia nigra pars compacta of diabetic rats, suggesting that this polyphenol could be a potential therapeutic option against diabetes-induced nigrostriatal dysfunctions.

Development and validation of a HPLC method using a monolithic column for quantification of trans-resveratrol in lipid nanoparticles for intestinal permeability studies

The development of nanodelivery systems that protect trans-resveratrol is extremely important to preserve its bioactive properties in the development of further applications as nutraceuticals to supplement foods and beverages. In this work, a validated HPLC method was developed for the quantification of trans-resveratrol in lipid nanoparticles for application in studies of in vitro intestinal permeability. The chromatographic separation was achieved in a C18 monolithic column connected to a fluorometric detector (330/374 nm), by isocratic elution consisting of 2% acetic acid/acetonitrile (80:20). Two calibration ranges were established (0.020-0.200 and 0.200-2.00 μmol L(-1)), and low quantification limits (2-6 nmol L(-1), 23-69 pg) were achieved. Stability studies showed that trans-resveratrol is stable for 24 h at 4 °C, and storage at room temperature and freeze-thaw cycles are not recommended. The proposed method was applied to in vitro intestinal permeability studies, in which values between 0.05 ± 0.01 and 1.8 ± 0.3 μmol L(-1) were found.

Treatment of obesity with the resveratrol-enriched rice DJ-526

Obesity is the most prevalent disease in the world which poses a serious risk for various chronic diseases. However, currently there are not any therapeutic agents that reduce body weight without causing serious side effects. In order to prevent and/or treat obesity and related diseases through a nutraceutical approach, we created a resveratrol-enriched transgenic rice accumulating 1.4 μg/g of resveratrol in its grain, DJ-526. Feeding of mice with the resveratrol-enriched rice DJ-526 showed excellent anti-obesity effect with reduction of body weights and abdominal fat volumes compared to the control by 20.0% and 31.3%, respectively. Also, the consumption of the resveratrol-enriched rice DJ526 significantly improved the blood lipid profiles and glucose levels in the animal experiments. Our resveratrol-enriched rice DJ-526 rice could provide both safe and convenient way for people with obesity and related diseases without major change of lifestyle or unwanted side effects from medication.

Creation of resveratrol-enriched rice for the treatment of metabolic syndrome and related diseases

Resveratrol has been clinically shown to possess a number of human health benefits. As a result, many attempts have been made to engineer resveratrol production in major cereal grains but have been largely unsuccessful. In this study, we report the creation of a transgenic rice plant that accumulates 1.9 µg resveratrol/g in its grain, surpassing the previously reported anti-metabolic syndrome activity of resveratrol through a synergistic interaction between the transgenic resveratrol and the endogenous properties of the rice. Consumption of our transgenic resveratrol-enriched rice significantly improved all aspects of metabolic syndrome and related diseases in animals fed a high-fat diet. Compared with the control animals, the resveratrol-enriched rice reduced body weight, blood glucose, triglycerides, total cholesterol, and LDL-cholesterol by 24.7%, 22%, 37.4%, 27%, and 59.6%, respectively. The resveratrol-enriched rice from our study may thus provide a safe and convenient means of preventing metabolic syndrome and related diseases without major lifestyle changes or the need for daily medications. These results also suggest that future transgenic plants could be improved if the synergistic interactions of the transgene with endogenous traits of the plant are considered in the experimental design.

The role of calcium channel blockers and resveratrol in the prevention of paraquat-induced parkinsonism in Drosophila melanogaster: a locomotor analysis

Studies have suggested that neuronal loss in Parkinson's disease (PD) could be related to the pacemaker activity of the substantia nigra pars compacta generated by L-type Ca(v) 1.3 calcium channels, which progressively substitute voltage-dependent sodium channels in this region during aging. Besides this mechanism, which leads to increases in intracellular calcium, other factors are also known to play a role in dopaminergic cell death due to overproduction of reactive oxygen species. Thus, dihydropyridines, a class of calcium channel blockers, and resveratrol, a polyphenol that presents antioxidant properties, may represent therapeutic alternatives for the prevention of PD. In the present study, we tested the effects of the dihydropyridines, isradipine, nifedipine, and nimodipine and of resveratrol upon locomotor behavior in Drosophila melanogaster. As previously described, paraquat induced parkinsonian-like motor deficits. Moreover, none of the drugs tested were able to prevent the motor deficits produced by paraquat. Additionally, isradipine, nifedipine, resveratrol, and ethanol (vehicle), when used in isolation, induced motor deficits in flies. This study is the first demonstration that dyhidropyridines and resveratrol are unable to reverse the locomotor impairments induced by paraquat in Drosophila melanogaster.

Resveratrol modulates astroglial functions: neuroprotective hypothesis

Resveratrol, a redox active compound present in grapes and wine, has a wide range of biological effects, including cardioprotective, chemopreventive, and anti-inflammatory activities. The central nervous system is a target of resveratrol, which can pass the blood-brain barrier and induce neuroprotective effects. Astrocytes are one of the most functionally diverse groups of cells in the nervous system, intimately associated with glutamatergic metabolism, transmission, synaptic plasticity, and neuroprotection. In this review, we focus on the resveratrol properties and response to oxidative insult on important astroglial parameters involved in brain plasticity, such as glutamate uptake, glutamine synthetase activity, glutathione content, and secretion of the trophic factor S100B.

Evaluation of the potential protective effects of ad libitum black grape juice against liver oxidative damage in whole-body acute X-irradiated rats

AIMS

The aim of this study was to evaluate the potential protective effects of ad libitum black grape (Vitis labrusca) juice against liver oxidative damage in whole-body acute X-irradiated rats.

MAIN METHODS

Animals were fed ad libitum and drank voluntarily black grape juice or placebo (isocaloric glucose and fructose solution) for 6 days before and 15 days following a 6 Gy X-irradiation from a 200 kV machine.

KEY FINDINGS

Irradiated animals receiving placebo showed a significant increase in the concentration of thiobarbituric acid-reactive substances (TBARS), a marker of lipid peroxidation, as well as a significant decrease in both Cu/Zn superoxide dismutase (Cu/ZnSOD) and glutathione peroxidase (GPx) activity and reduced glutathione concentration (GSH). Black grape juice supplementation resulted in a reversal of lipid peroxidation, Cu/ZnSOD activity, and GSH concentration, towards values not significantly differing from those in non-irradiated, placebo-supplemented rats. Poly(ADP-ribose) polymerase (PARP-1) and Cu/ZnSOD changes in protein expression were observed for irradiated rats. No change in p53 expression or DNA fragmentation was found.

SIGNIFICANCE

Ad libitum black grape juice intake is able to restore the liver primary antioxidant system against adverse effects due to whole-body acute X-irradiation in rats after 15 days post-irradiation. The results support using antioxidant supplements as a preventive tool against radiation-induced harm.

Multivariant optimization, validation, and application of capillary electrophoresis for simultaneous determination of polyphenols and phenolic acids in Brazilian wines

A method for the simultaneous determination of the stilbene resveratrol, four phenolic acids (syringic, coumaric, caffeic, and gallic acids), and five flavonoids (catechin, rutin, kaempferol, myricetin, and quercetin) in wine by CE was developed and validated. The CE electrolyte composition and instrumental conditions were optimized using 2(7-3) factorial design and response surface analysis, showing sodium tetraborate, MeOH, and their interaction as the most influential variables. The optimal electrophoretic conditions, minimizing the chromatographic resolution statistic values, consisted of 17 mmol/L sodium tetraborate with 20% methanol as electrolyte, constant voltage of 25 kV, hydrodynamic injection at 50 mbar for 3 s, and temperature of 25 degrees C. The R(2) values for linearity varied from 0.994 to 0.999; LOD and LOQ were 0.1 to 0.3 mg/L and 0.4 to 0.8 mg/L, respectively. The RSDs for migration time and peak area obtained from ten consecutive injections were less than 2% and recoveries varied from 97 to 102%. The method was applied to 23 samples of inexpensive Brazilian wines, showing wide compositional variation.

Trans- and cis-resveratrol concentration in wines produced in Serbia

Resveratrol, which occurs in two isomeric forms, trans and cis, is a phytoalexin with numerous pharmacological activities, such as anti-cancer, antiviral, neuroprotective and anti-aging. Red wine is the main source of the compound and an easy way of including resveratrol in the human diet. In this study, the most popular commercial Serbian wines (red, white and ros?-type) were analyzed for their content of trans- and cis-resveratrol. The analysis was performed by HPLC with a UV detector. Prior to the injection, phenolic compounds were extracted onto a LiChrolut RP18 bonded silica cartridge. The concentration of trans-resveratrol ranged from 0.11 to 1.69 mg L-1 and cis-resveratrol from 0.12 to 1.49 mg L-1.