RESUMO
Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum allowed copper (II) ion doses in wine grapes at harvest can have on aged wine quality. This was the focus of the present study. We investigated the copper (II) effects by producing both white and red wines from musts containing three initial metal concentrations according to the limits set for organic farming. In detail, the influence of copper (II) on fermentation evolution, chromatic characteristics, and phenolic compounds was evaluated. Interestingly, the white wine obtained with the highest permitted copper (II) dose initially exceeded the concentration of 1.0 mg/L at fermentation completion. However, after one year of storage, the copper (II) content fell below 0.2 ± 0.01 mg/L. Conversely, red wines showed copper (II) levels below 1.0 mg/L at the end of fermentation, but the initial copper (II) level in musts significantly affected total native anthocyanins, color intensity, hue, and acetaldehyde concentration. After 12-month aging, significant differences were observed in polymeric pigments, thus suggesting a potential long-term effect of copper (II) on red wine color stability.
Assuntos
Acetaldeído , Cobre , Fermentação , Fenóis , Vitis , Vinho , Vinho/análise , Cobre/análise , Acetaldeído/análise , Fenóis/análise , Fenóis/química , Vitis/química , Cor , Antocianinas/análise , Antocianinas/químicaRESUMO
BACKGROUND: Climate changes have been leading to an excessive synthesis of quercetin (Q) and its glycosides (Q-Gs) in specific red grape varieties, such as Sangiovese. This has resulted in concentrations overcoming the solubility threshold of Q in wines, with the consequent formation of undesirable precipitates. This study aims at assessing the impact of various factors, including anthocyanins, temperature, nucleation seeds and time, on the precipitation of Q in red wine. RESULTS: The influence of anthocyanins on Q solubility was examined by adding a grape skin extract rich in anthocyanins to a model solution containing 89 µmol L-1 of Q. The data revealed that the solubility of both Q and Q-Gs increased as a function of the anthocyanin concentration in the model solution. In a subsequent experiment, red wines were stored at two different temperatures (2 and 20 °C), supplemented with Q nucleation seeds, and monitored over a 10-day period. Notably, after only 3 days of contact with Q seeds at 2 °C, a reduction of over 75% in Q concentration was observed in the supernatant. Among the considered factors, contact with nucleation seeds emerged as the most significant one (P < 0.0001). CONCLUSION: Q precipitation in red wines is influenced by the presence of anthocyanins in solution, although it is not the sole determinant. The data also suggested that a potential strategy for wineries to mitigate the risk of Q precipitation in bottled wine would be the acceleration of this process by promoting the formation of nucleation seeds. © 2024 Society of Chemical Industry.
Assuntos
Antocianinas , Quercetina , Sementes , Vitis , Vinho , Antocianinas/química , Antocianinas/análise , Quercetina/química , Quercetina/análise , Vinho/análise , Vitis/química , Sementes/química , Precipitação Química , Temperatura , Solubilidade , Frutas/química , Extratos Vegetais/químicaRESUMO
Climate change is causing a significant decrease in the total acidity of grapes and related wines. This represents a serious issue for sparkling wine production. Consequently, before the second fermentation, the acidification of base wines is often necessary. However, the impacts of the most important organic acids on the foam properties of sparkling wines are not yet well known. The impacts of the addition of tartaric, malic, citric, and lactic acid on the quality of Falanghina and Bombino sparkling wines were evaluated. Analyses were performed soon after the second fermentation and one year after aging sur lees. The addition of each different organic acid to the two base wines resulted in significant changes in the sparkling wines not only in terms of pH, titratable acidity, and buffering capacity but also in the content of total amino acids and, in some cases, in the height of the foam and its stability over time. For both grape varieties, acidified wines showed a lower content of total amino acids in comparison with the control wines. The addition of lactic acid determined a higher persistency of the foam even after one year of aging sur lees only in Falanghina wines. The results obtained herein highlight the importance of organic acids and the pH of the base wines for the content of amino acids in sparkling wines. No strict correlation between organic acid addition and the foamability of wines was observed.
Assuntos
Vitis , Vinho , Vinho/análise , Vitis/química , Compostos Orgânicos , Aminoácidos/análise , Ácido LácticoRESUMO
The cultivated grapevine, Vitis vinifera subsp. vinifera, possesses a rich biodiversity with numerous varieties. Each variety adapts differently to varying pedoclimatic conditions, which greatly influence the terroir expression of wine regions. These conditions impact vine growth, physiology, and berry composition, ultimately shaping the unique characteristics and typicity of the wines produced. Nowadays, the potential of the different adaptation capacities of grape varieties has not yet been thoroughly investigated. We addressed this issue by studying two grape varieties, Aglianico and Cabernet Sauvignon, in two different pedoclimatic conditions of Southern Italy. We evaluated and compared the effect of different pedoclimatic conditions on plant physiology, the microbial quality of grapes using Next-Generation Sequencing (NGS) technology, the expression trends of key genes in ripe berries and the concentration of phenolic compounds in grapes and wines by HPLC-MS, HPLC-DAD, NMR and spectrophotometric analyses. Metabolomic and microbiome data were integrated with quantitative gene expression analyses to examine varietal differences and plasticity of genes involved in important oenological pathways. The data collected showed that the phenotypic response of studied grapes in terms of vigor, production, and fruit quality is strongly influenced by the pedoclimatic conditions and, in particular, by soil physical properties. Furthermore, Aglianico grape variety was more influenced than the Cabernet Sauvignon by environmental conditions. In conclusion, the obtained findings not only reinforce the terroir concept and our comprehension of grape's ability to adapt to climate variations but can also have implications for the future usage of grape genetic resources.
RESUMO
Acetaldehyde plays a key role in determining some wine properties. Interesting is the reaction of acetaldehyde with flavonoids, as the ensuing products can alter wine color, astringency, colloidal stability. Many studies reported on the formation of ethylidene-bridged flavan-3-ols as products of the reaction between acetaldehyde and either (+)-catechin or (-)-epicatechin. In white wines after one year of incubation with acetaldehyde only vinyl-(+)-catechin and vinyl-(-)-epicatechin were observed, while no ethylidene linked oligomers were detected. This observation prompted us to study the reaction of (+)-catechin with acetaldehyde in wine model solution through an experimental and theoretical approach, with the purpose of exploring the nature of the species involved along with the mechanisms leading to them. The products of the reaction were observed over 38 days. The results showed that ethylidene-bridged catechins are the first products to be formed but over time the dissociation of these dimers causes vinyl-catechins to accumulate.
Assuntos
Catequina , Vinho , Catequina/análise , Acetaldeído , Flavonoides/análise , Vinho/análise , Modelos TeóricosRESUMO
BACKGROUND: Numerous oenological practices can cause an excess of dissolved oxygen in wine, thus determining sensory and chromatic defects in the short- to long-term. Hence, it is necessary to manage the excess of oxygen before bottling. METHODS: In this study, the management of the dissolved oxygen content by a polypropylene hollow fiber membrane contactor apparatus was performed in two wines from different grape varieties (Aglianico and Falanghina). The wines were analyzed after an 11-month aging. Anthocyanins and acetaldehyde content were evaluated by HPLC. In addition, other phenolic compounds and chromatic characteristics were analyzed by spectrophotometric methods. NMR and HR ESIMS analyses were conducted to evaluate the amount of pyranoanthocyanins and polymeric pigments. RESULTS: After 11 months of aging, in both wines a decrease of free and total SO2 with respect to initial values was detected. In the wines with the highest dissolved oxygen levels, a more remarkable loss was observed. No significant differences in terms of color parameters were detected. In red wine with the highest oxygen content, a massive formation of polymeric pigments and BSA reactive tannins was observed, as opposed to wines with lower oxygen levels. CONCLUSION: The study demonstrated that the membrane contactor can prove a successful tool to manage dissolved oxygen in wines as to prevent their oxidative spoilage.
Assuntos
Acetaldeído/química , Antocianinas/química , Oxigênio/metabolismo , Fenóis/química , Polipropilenos/química , Vitis/química , Vinho/análise , Oxirredução , Oxigênio/análiseRESUMO
Dietary phenolic compounds possess potent bioactivity against inflammatory pathways of chronic inflammatory conditions, such as type 2 diabetes. Here, the phenolic profile and bioactivity of Italian red wines Gaglioppo, Magliocco, and Nerello Mascalese were characterized. NMR, HPLC/UV-Vis and spectrophotometric characterization showed that Magliocco was the richest wine in monomeric anthocyanins (two-fold), catechins, and low molecular weight phenolics (LMWP). A positive correlation was observed between the polyphenolic content and antioxidant capacity (p < 0.05), with Magliocco displaying the highest antioxidant capacity (p < 0.01). In vitro evidence on the endothelial cell models of insulin resistance and hyperglycemia showed the ability of Magliocco to reduce reactive oxygen species (ROS) (p < 0.01) and cytokine release (p < 0.01) and to upregulate SIRT1 and SIRT6 (p < 0.01). On the whole, the results indicated that the quantitative and qualitative phenolic profiles of red wines influence their in vitro beneficial effects on oxidative and proinflammatory milieu in endothelial cells, showing a positive modulation of SIRT1 and SIRT6, both implied in vascular aging.
Assuntos
Antioxidantes/farmacologia , Células Endoteliais/enzimologia , Fenóis/farmacologia , Sirtuína 1/metabolismo , Sirtuínas/metabolismo , Vinho , Antioxidantes/química , Linhagem Celular , Humanos , Fenóis/químicaRESUMO
BACKGROUND: Three accelerated oxidation tests were proposed to simulate red wine oxidation thus providing information useful to correctly manage moderate oxygen exposure of wine during aging in regard to phenolic composition and wine color. Since the results of the tests have never been compared on wines with different initial composition, the aim of this study was to find a suitable method to simulate oxidation of any still red wine. METHODS: Aglianico, Barbera, Gaglioppo, Magliocco, and Nerello wines were treated with (1) three cycles of air saturation, (2) the addition of hydrogen peroxide, and (3) the addition of acetaldehyde. Changes in chromatic characteristics and phenolic composition were determined by spectrophotometric and HPLC methods. RESULTS: Important differences in the behavior of the different wines were detected: the highest formation of polymeric pigments was observed in Barbera and Aglianico wines. In contrast, Gaglioppo and Magliocco wines showed a lower variability before and after the oxidation probably due to the lower anthocyanin/tannin ratio. Among the accelerated oxidation tests applied, no significant differences in color parameters and phenolic composition were detected in samples treated with the addition of H2O2 and the air saturation method. CONCLUSION: The study demonstrated that H2O2 addition is a successful tool to predict the evolution of different phenolic compounds during the air saturation treatment of wines.
Assuntos
Análise de Alimentos/métodos , Vinho/análise , Acetaldeído/análise , Cor , Cinética , OxirreduçãoRESUMO
BACKGROUND: In the wine industry, in addition to condensed tannins of grape origin, other commercial tannins are commonly used. However, the influence of oxygen uptake related to different tannin additions during the post fermentative phase in wine has not been completely investigated. In this study, we evaluated the influence of four different commercial tannins (namely, condensed tannins, gallotannins, ellagitannins and tea tannins) during four saturation cycles. METHOD: Wine samples were added with four different tannin classes (30 g/hL) as to have 5 different experimental samples: control, gallotannins (GT), condensed tannins (CT), ellagitannins (ET), and tea tannins (TT). The chemical composition of the four commercially available tannin mixtures was defined by means of NMR and high-resolution mass spectrometry. After the addition of tannins, each wine sample was oxidized by air over four cycles of saturation. During the experiment oxygen consumption rate (OCR), sulfur dioxide consumption, acetaldehyde production, phenolic compounds, chromatic characteristics, astringency measured by the reactivity towards saliva proteins and astringency subqualities were evaluated. RESULTS: The experiment lasted 52 days. The addition of tannins influenced the oxygen consumption on the 1st day of the saturation cycles and, in the case of TT, a higher total consumption of oxygen was also detected. Acetaldehyde increased during the experiment while the native anthocyanins decreased throughout the oxidation process. CONCLUSION: Wines added with tannins featured improved color intensities with respect to the control; the addition of TT, GT and ET slightly promoted the formation of short polymeric pigments; the astringency, determined before and at the end of the experiment, decreased in all the samples, including the control wine, and mostly in the ET and GT samples.
Assuntos
Fenóis/química , Taninos/química , Vinho , Adstringentes/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Consumo de Oxigênio/fisiologiaRESUMO
Wines produced from Sangiovese (sg) grapes, the most cultivated red grape variety in Italy and widely grown across the world, is often subjected to loss of clarity due to the formation of a deposit constituted by fine needle-shaped crystals. In this work, a qualitative study by 1H-NMR and 13C-NMR analysis of the deposit obtained by filtering cloudy sg wines showed that it was constituted by crystals of quercetin (Q). The analysis of hydro-alcoholic solutions (12% ethanol and pH 3.2.) and red wines added with increasing amounts of Q showed that, above 3 mgL-1 of Q, a deposit can be detected and, the time necessary for its formation depends on the medium. The comparison among sg and other 11 monovarietal wines showed that sg was the richest in Q and quercetin glycosides (GQ). Both Q and GQ decreased in the analyzed solutions over time and the decrease was faster for Q than for GQ. The controlled exposure to oxygen determined a decrease of Q higher than the 50% of the initial values. Data obtained in this study suggested that practices as micro-oxygenation and wood aging could help to decrease the amount of Q in sg wines.
RESUMO
The Alpine wormwood Artemisia vallesiaca All. was considered the most valuable ingredient of vermouth, a celebrated aromatized wine. A. vallesiaca has a very limited geographical distribution, and the booming market of vermouth decimated its natural population, resulting in the eventual replacement of this rare species with more common and less expensive wormwoods like A. absinthium L.. Over the past years, attempts to revive the original recipe(s) of vermouth have fostered the establishment of cultivations of A. vallesiaca in pre-montane settings. In order to assist these projects, the phytochemical profile of cultivated plants and of several native populations of A. vallesiaca from the Swiss Valais were comparatively evaluated, focusing on sesquiterpene lactones and on lipophilic flavonoids, the hallmark constituents of Artemisia species. Remarkably, no significant difference was detected between the samples, despite the different origins. The lipophilic flavonoids of A. vallesiaca were similar to those of related species used in the production of vermouth, but the presence of C-9 oxygenated 11ß-methyl germacranolides and eudesmanolides (herbolides) made its sesquiterpene lactone profile peculiar. In addition to known compounds, two novel germacranolides were also characterized (herbolides J and K), and the major sesquiterpene lactone from the plant, the bitter germacranolide herbolide D (4), was detected and quantified by 1H NMR in a bitter liqueur aromatized with A. vallesiaca. Taken together, these observations qualify herbolides as marker to identify A. vallesiaca in aromatized alcohol matrixes.
Assuntos
Artemisia/química , Lactonas/química , Sesquiterpenos de Germacrano/química , Vinho , Itália , Compostos Fitoquímicos/químicaRESUMO
Anthocyanins are natural pigments responsible for the typical color of red wines and are critically associated with the wine commercial value and longevity. Thus, understanding the molecular bases of the anthocyanin chemical behavior in the complex wine environment is a central issue to the enological sector. By setting up a nuclear-magnetic-resonance-based experimental protocol, new important insights into the chemistry of malvidin-3- O-glucoside, a major wine anthocyanin, in model solution have been provided. Two new equilibrating isomers of the anthocyanin have been identified and quantified at typical wine pH values. More importantly, the key role of pH in determining the solubility and co-pigmentation process of malvidin-3- O-glucoside has been clarified. Consequently, a value of pH of about 3.3 or lower favors co-pigmentation while inhibiting the precipitation of significant quantities of anthocyanins during the maceration-extraction phase of the winemaking.
Assuntos
Antocianinas/química , Glucosídeos/química , Vinho/análise , Cor , Concentração de Íons de Hidrogênio , IsomerismoRESUMO
Experimental evidence suggests that moderate consumption of wine has health promoting properties that have been mainly attributed to the wine polyphenol content. However, a systematic analysis of the major healthy molecules contained in wines has not been conducted yet. Our study explored the potential arsenal of beneficial molecules contained in wine from both a qualitative and quantitative perspective. The experimental approach was based on chromatography and untargeted NMR spectroscopy. In addition to already known bioactive molecules, for the first time, xanthurenic acid and oleanic acid were identified in wine in relatively high concentrations. On account of their many biological activities, these two molecules widen the range of potential beneficial effects of wine and pave the way toward the evaluation of their still unexplored sensory properties.
Assuntos
Ácido Oleanólico/análise , Compostos Fitoquímicos/análise , Vinho/análise , Xanturenatos/análise , Espectroscopia de Ressonância Magnética , Ácido Oleanólico/química , Triterpenos Pentacíclicos , Triterpenos/química , Vitis/química , Vitis/metabolismo , Ácido BetulínicoRESUMO
Vitis vinifera cv Falanghina is an ancient grape variety of Southern Italy. A thorough phytochemical analysis of the Falanghina leaves was conducted to investigate its specialised metabolite content. Along with already known molecules, such as caftaric acid, quercetin-3-O-ß-d-glucopyranoside, quercetin-3-O-ß-d-glucuronide, kaempferol-3-O-ß-d-glucopyranoside and kaempferol-3-O-ß-d-glucuronide, a previously undescribed biflavonoid was identified. For this last compound, a moderate bioactivity against metastatic melanoma cells proliferation was discovered. This datum can be of some interest to researchers studying human melanoma. The high content in antioxidant glycosylated flavonoids supports the exploitation of grape vine leaves as an inexpensive source of natural products for the food industry and for both pharmaceutical and nutraceutical companies. Additionally, this study offers important insights into the plant physiology, thus prompting possible technological researches of genetic selection based on the vine adaptation to specific pedo-climatic environments.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Biflavonoides/isolamento & purificação , Folhas de Planta/química , Vitis/química , Antineoplásicos Fitogênicos/farmacologia , Biflavonoides/farmacologia , Linhagem Celular Tumoral , Humanos , Itália , Melanoma , Estrutura Molecular , Compostos Fitoquímicos/análiseRESUMO
Lycium barbarum (Solanaceae), long known to the traditional Chinese medicine because of its many health-promoting effects, has of late spread widely across the Western hemisphere, mainly on account of the nutritional richness in vitamins, minerals and antioxidant metabolites of its fruits. Data on bioactive metabolites from fruits and leaves, which are commonly consumed in soups and salads, are scarce and sometimes even contradictory. By means of NMR, the present study identified the specialised products contained in an Italian cultivar of L. barbarum. Kaempeferol, caffeic acid, 3,4,5-trihydroxycinnamic acid and 5-hydroxyferulic acid were found in fresh fruits; rutin and chlorogenic acid were detected in leaves and flowers; also, a previously undescribed N,N-dicaffeoylspermidine derivative was identified in flowers, while N-feruloyltyramine derivatives, for which interesting anti-inflammatory properties have been reported, turned out to be the major bioactive molecules in stems. The plethora of the detected bioactive molecules amplifies the nutraceutical value of berries and leaves and prompts the exploitation of L. barbarum flowers and pruned stems as sources of beneficial compounds.
Assuntos
Ácidos Cafeicos/análise , Ácido Clorogênico/análise , Ácidos Cumáricos/análise , Inibidores Enzimáticos/análise , Lycium/química , Rutina/análise , Tiramina/análogos & derivados , Araquidonato 5-Lipoxigenase/metabolismo , Ácidos Cafeicos/metabolismo , Ácidos Cafeicos/farmacologia , Linhagem Celular Tumoral , Ácido Clorogênico/metabolismo , Ácido Clorogênico/farmacologia , Ácidos Cumáricos/metabolismo , Ácidos Cumáricos/farmacologia , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Flores/química , Frutas/química , Humanos , Itália , Espectroscopia de Ressonância Magnética , Medicina Tradicional Chinesa , Folhas de Planta/química , Rutina/metabolismo , Rutina/farmacologia , Tiramina/análise , Tiramina/metabolismo , Tiramina/farmacologiaRESUMO
Ziziphus jujuba Mill., jujube, leaf infusions are popular bedtime beverages as they improve sleep by soothing the nerves. With the aim of providing further insights into the polyphenol content of jujube leaf infusion and their antioxidant activities, a 2,2-diphenyl-1-picrylhydrazyl (DPPH)-guided purification of the aqueous extract of Z. jujuba Mill. leaves was conducted. Three major antioxidant polyphenols (i.e. quercitrin, catechin and gallocatechin) of the leaves were identified. In addition, a significant antibiofilm bioactivity against Streptococcus mutans, a causative agent of human dental caries, was detected for the aqueous leaf extract and its bio-guided separation resulted in the identification of the lupane triterpenoid alphitolic acid as the main antibiofilm metabolite. The results herein presented further promote the consumption of jujube leaf infusion as a healthy antioxidant bedtime beverage, and associate it to an unreported anti-caries activity.
Assuntos
Antibacterianos/farmacologia , Flavonoides/análise , Folhas de Planta/química , Streptococcus mutans/efeitos dos fármacos , Triterpenos/farmacologia , Ziziphus/química , Antioxidantes/análise , Cárie Dentária/microbiologia , Humanos , Extratos Vegetais/química , Folhas de Planta/metabolismo , Triterpenos/análiseRESUMO
Palytoxin (PLTX) and its analogues have been detected as seafood contaminants associated with a series of human foodborne poisonings. Due to a number of fatalities ascribed to the ingestion of PLTX-contaminated marine organisms, the development of methods for its detection in seafood has been recommended by the European Food Safety Authority (EFSA). Due to its feasibility, the spectrophotometric hemolytic assay is widely used to detect PLTX in different matrices, even though a standardized protocol is still lacking. Thus, on the basis of available assay procedures, a new standardized protocol was set up using purified human erythrocytes exposed to PLTX (working range: 3.9 × 10(-10)-2.5 × 10(-8) M) in a K(+)-free phosphate buffered saline solution, employing a 5 h incubation at 41 °C. An intra-laboratory characterization demonstrated its sensitivity (limit of detection, LOD = 1.4 × 10(-10) M and quantitation, LOQ = 3.4 × 10(-10) M), accuracy (bias = -0.8%), repeatability (RSDr = 15% and 6% for intra- and inter-day repeatability, respectively) and specificity. However, the standardized method seems not to be suitable for PLTX quantitation in complex matrices, such as mussel (Mytilus galloprovincialis) extracts, at least below the limit suggested by EFSA (30 µg PLTXs/Kg shellfish meat). Thus, the hemolytic assay for PLTX quantitation in seafood should be used only after a careful evaluation of the specific matrix effects.
Assuntos
Acrilamidas/análise , Bivalves/química , Hemólise/efeitos dos fármacos , Acrilamidas/toxicidade , Animais , Venenos de Cnidários , Reações Cruzadas , Eritrócitos/efeitos dos fármacos , Humanos , Limite de Detecção , Reprodutibilidade dos TestesRESUMO
Humulus lupulus (hop plant) has long been used in traditional medicine as a sedative and antimicrobial agent. More recently, attention has been devoted to the phytoestrogenic activity of the plant extracts as well as to the anti-inflammatory and chemopreventive properties of the prenylated chalcones present. In this study, an Italian sample of H. lupulus cv. "Cascade" has been investigated and three new compounds [4-hydroxycolupulone (6), humudifucol (7) and cascadone (8)] have been purified and identified by means of NMR spectroscopy along with four known metabolites. Notably, humudifucol (7) is the first prenylated dimeric phlorotannin discovered in nature. Because structurally related phloroglucinols from natural sources were found previously to inhibit microsomal prostaglandin E2 synthase (mPGES)-1 and 5-lipoxygenase (5-LO), the isolated compounds were evaluated for their bioactivity against these pro-inflammatory target proteins. The prenylated chalcone xanthohumol inhibited both enzymes at low µM concentrations.
Assuntos
Chalconas/isolamento & purificação , Chalconas/farmacologia , Humulus/química , Fitoestrógenos/isolamento & purificação , Fitoestrógenos/farmacologia , Plantas Medicinais/química , Polifenóis/isolamento & purificação , Polifenóis/farmacologia , Araquidonato 5-Lipoxigenase , Chalconas/química , Flavonoides , Oxirredutases Intramoleculares/antagonistas & inibidores , Itália , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Fitoestrógenos/química , Extratos Vegetais/química , Polifenóis/química , Prenilação , Propiofenonas , Prostaglandina-E SintasesRESUMO
This study provides the first evaluation of the cytotoxic effects of the recently identified palytoxin (PLTX) analog, ovatoxin-a (OVTX-a), the major toxin produced by Ostreopsis cf. ovata in the Mediterranean Sea. Its increasing detection during Ostreopsis blooms and in seafood highlights the need to characterize its toxic effects and to set up appropriate detection methods. OVTX-a is about 100 fold less potent than PLTX in reducing HaCaT cells viability (EC50 = 1.1 × 10(-9) M vs 1.8 × 10(-11) M, MTT test) in agreement with a reduced binding affinity (Kd = 1.2 × 10(-9) vs 2.7 × 10(-11) M, saturation experiments on intact cells). Similarly, OVTX-a hemolytic effect is lower than that of the reference PLTX compound. Ost-D shows the lowest cytotoxicity toward HaCaT keratinocytes, suggesting the lack of a hydroxyl group at C44 as a critical feature for PLTXs cytotoxic effects. A sandwich ELISA developed for PLTX detects also OVTX-a in a sensitive (LOD = 4.2 and LOQ = 5.6 ng/mL) and accurate manner (Bias = 0.3%), also in O. cf. ovata extracts and contaminated mussels. Although in vitro OVTX-a appears less toxic than PLTX, its cytotoxicity at nanomolar concentrations after short exposure time rises some concern for human health. The sandwich ELISA can be a viable screening method for OVTXs detection in monitoring program.
Assuntos
Dinoflagellida/química , Toxinas Marinhas/toxicidade , Acrilamidas , Animais , Bivalves/química , Linhagem Celular , Venenos de Cnidários , Ensaio de Imunoadsorção Enzimática , Humanos , Toxinas Marinhas/isolamento & purificação , Mar Mediterrâneo , Alimentos Marinhos , Frutos do Mar , Testes de ToxicidadeRESUMO
Blooms of benthic dinoflagellates of the genus Ostreopsis (mainly O. cf. ovata and occasionally O. cf. siamensis) represent a serious concern for humans in the Mediterranean area, due to production of palytoxin-like compounds listed among the most potent marine toxins known. In this work, six strains of Ostreopsis sp. from Cyprus Island were analyzed through an integrated approach based on molecular, chemical, and eco-toxicological methods. Cypriot Ostreopsis sp. was found to be a species distinct from O. cf. ovata and O. cf. siamensis, belonging to the Atlantic/Mediterranean Ostreopsis spp. clade. Some variability in toxin profiles emerged: three strains produced ovatoxin-a (OVTX-a), OVTX-d, OVTX-e, and isobaric palytoxin, so far found only in O. cf. ovata; the other three strains produced only new palytoxin-like compounds, which we named ovatoxin-i, ovatoxin-j1, ovatoxin-j2, and ovatoxin-k. The new ovatoxins present the same carbon skeleton as ovatoxin-a, differing primarily in an additional C2H2O2 moiety and an unsaturation in the region C49-C52. Other minor structural differences were found, including the presence of a hydroxyl group at C44 (in OVTX-j1 and OVTX-k) and the lack of a hydroxyl group in the region C53-C78 (in OVTX-i and OVTX-j1). The toxin content of the analyzed Ostreopsis sp. strains was in the range 0.06-2.8 pg cell(-1), definitely lower than that of a Ligurian O. cf. ovata strain cultured under the same conditions. Accordingly, an eco-toxicological test on Artemia salina nauplii demonstrated that Ostreopsis sp. presents a very low toxicity compared to O. cf. ovata. The whole of these data suggest that Ostreopsis sp. from Cyprus Island poses a relatively low risk to humans.