Ion-pair dispersive liquid–liquid microextraction solidification of floating organic droplets method for the rapid and sensitive detection of phenolic acids in wine samples using liquid chromatography combined with a core–shell particle column

This study describes a novel sample preparation method for extraction of phenolic acids from wine using ion pair dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet (IP-DLLME-SFO). The ion-pairing technique combined with DLLME-SFO dramatically enhanced the extraction efficiency for very polar phenolic acids, such as gallic acid and protocatechuic acid, which could not be extracted by DLLME-SFO in the absence of an ion-pairing reagent. The effects of the parameters that can affect the extraction efficiency were systematically investigated, including the type and concentration of ion-pairing reagent, type and volume of extraction and dispersive solvents, extraction time, sample pH, and ion strength. The method linearity was constructed in the range of 0.01–15 μg/mL, and the sensitivity expressed as limit of detection was as low as 10 ng/mL. The method that we developed was applied for the analysis of commercial wine samples, revealing different levels of phenolic acids among these products.     

Total phenolic contents and free-radical scavenging activities of grape (Vitis vinifera L.) and grape products

Grape is one of the world's largest fruit crops, with an approximate annual production of 58 million metric tons, and it is well known that the grape skins, seeds and stems, waste products generated during wine and grape juice processing, are rich sources of polyphenols. It contains flavonoids, phenolic acids and stilbenes. In this study, we tried to determine antioxidant properties and phenolic contents of grape and grape products (fresh fruit, seed, dried fruit, molasses, pestil, vinegar) of ethanol and water extracts. Antioxidant properties of extracts were investigated by DPPH^√, ABTS^√+, superoxide, H₂O₂ scavenging, reducing power, metal chelating activity and determination of total phenolic contents. The seed extracts revealed highest ABTS^√+, DPPH^√, H₂O₂ scavenging and reducing power activities. Furthermore, these extracts showed higher total phenolic contents than other grape product extracts.     

Chemical Characterization Of Commercial Balsamic Vinegar Glaze

The present study reports the chemical characterization of commercial balsamic vinegar glaze (BVG), a side product of the world-famous Aceto Balsamico di Modena (ABM). BVG, originally a homemade sweet and sour sauce, is now produced on an industrial scale and is gaining a growing success. The determination of total titratable acidity, dry matter, ash, metals, sugars, phenolic acids and furfurals is reported for BVG samples of different batches and years of production. Principal component analysis (PCA) and ANOVA test were applied to evaluate the experimental data. The results showed that the chemical characteristics of the product are almost unchanged in the investigated years and well reflect the characteristics of the ABM. Moreover, it was found that potentially harmful species, namely furfural compounds and heavy metals, were at a lower concentration than that of homologous products. In particular, the concentration of heavy metals, such as Cu, Zn and Pb, suggests that a preventive demetallization of the BVG starting raw materials occurs.     

Phenolics and abscisic acid identified in acacia honey comparing different SPE cartridges coupled with HPLC-PDA

The major components of honey are sugar and water, but some phenolic compounds may be responsible for honey quality. We investigated the effects of four reversed-phase (RP) and four reversed-phase and anion-exchange (RP-AE) solid-phase extraction (SPE) cartridges as a pre-concentration technique for honey phenolics. Eleven acacia honey samples were collected from different apiaries of China and their levels of phenolics and abscisic acid were analyzed using high-performance liquid chromatography (HPLC). Our results reveal that RP-AE SPE cartridges are superior to RP SPE cartridges for the pre-concentration of honey phenolics. The improved pre-concentration effect of RP-AE SPE cartridges may be a novel finding of our research. The Strata-X-A cartridge may be used in the concentration of low content phenolics of complex food matrices. We identified cis-trans-abscisic acid and 19 phenolics occurring in acacia honey samples. Seven phenolic compounds and abscisic acid were identified in almost all samples, representing 50% of total phenolics. Abscisic acid possesses the highest average content of 146.0 μg/100 g, and pinobanksin also presented the highest average of 53.1 μg/100 g among all flavonoids. Moreover, we infer that abscisic acid could be the solid ingredient for adulteration identification and quality control of acacia honey.     

Cardioprotective actions of grape polyphenols

The aim of this review is to discuss the accumulating evidence that suggests that grape extracts and purified grape polyphenols possess a diverse array of biological actions and may be beneficial in the prevention of some inflammatory-mediated diseases including cardiovascular disease. The active components from grape extracts, which include the grape seed, grape skin, and grape juice, that have been identified thus far include polyphenols such as resveratrol, phenolic acids, anthocyanins, and flavonoids. All possess potent antioxidant properties and have been shown to decrease low-density lipoprotein–cholesterol oxidation and platelet aggregation. These compounds also possess a range of additional cardioprotective and vasoprotective properties including antiatherosclerotic, antiarrhythmic, and vasorelaxation actions. Although not exclusive, antioxidant properties of grape polyphenols are likely to be central to their mechanism(s) of action, which also include cellular signaling mechanisms and interactions at the genomic level. This review discusses some of the evidence favoring the consumption of grape extracts rich in polyphenols in the prevention of cardiovascular disease. Consumption of grape and grape extracts and/or grape products such as red wine may be beneficial in preventing the development of chronic degenerative diseases such as cardiovascular disease     

Antioxidant compounds and antioxidant activity in acerola (Malpighia emarginata DC.) fruits and derivatives

Acerola (Malpighia emarginata DC.) is a wild plant from Central America. This fruit is well known as an excellent food source of vitamin C, and it also contains phytochemicals such as carotenoids and polyphenols. The present work evaluates the antioxidant capacity of hydrophilic extracts of acerola pulps and juices by 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ORAC and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Antioxidant activity values obtained for acerola juice were higher than those reported for other fruit juices particularly rich in polyphenols such as strawberry, grape and apple juices, among others. Vitamin C, total phenol index (TPI), total anthocyanins and polyphenolic compounds by high performance liquid chromatography (HPLC), as main factors responsible for antioxidant activity, were determined. Contents in total ascorbic acid ranged from 6.32 to 9.20 g kg⁻¹ of pulp and 9.44 to 17.97 g L⁻¹ of juice. Five different polyphenolic compounds were identified in the samples by means of HPLC and diode-array detection: chlorogenic acid, (−)-epigallocatechin gallate, (−)-epicatechin, procyanidin B1 and rutin, being the two last predominant. By means of solid phase extraction (SPE) three soluble polyphenolic fractions (phenolic acids, anthocyanins and flavonoids) were separated from the different sample extracts, and their respective antioxidant activities calculated. Among them, phenolic acids are the main contributors to the antioxidant activity.     

超高效液相色谱-二极管距阵检测器法同时测定水中7种有机酚

目的:建立水中7种有机酚类污染物的超高效液相色谱-二极管距阵检测器测定方法。方法:水样经OasisHLB小柱富集,利用ACQUITY UPLCBEH C8(50 mm×2.1 mm×1.7μm)色谱柱分离,以甲醇和0.1%乙酸溶液为流动相进行梯度淋洗,流速0.25 ml/min,采用PDA检测器,在波长275 nm和303 nm进行测定,外标法定量。结果:7种酚类化合物在0.05 mg/L～5.0 mg/L浓度范围呈线性关系,其相关系数均大于0.999,检出限为15.0μg/L～25.0μg/L,方法回收率在86.9%～104.1%,相对标准差均小于5%。结论:该法灵敏、高效、准确,适用于水中七种酚类污染物的测定。     

Cylindrospermopsin determination in water by LC-MS/MS: Optimization and validation of the method and application to real samples

A new method for determining dissolved cylindrospermopsin (CYN) in waters using solid-phase extraction (SPE) with graphitized carbon cartridges and quantification by liquid chromatography coupled with tandem mass spectrometry is described and discussed. The method has been suitably validated: the linear range covered is from 0.900 to 125?μg CYN/L. Limits of detection and quantification were 0.5 and 0.9?μg CYN/L, respectively, and allow CYN determination at concentrations below the guideline proposed of 1?μg CYN/L in natural waters. The method exhibits mean recoveries from 83 to 95%, and intermediate precision (relative standard deviation (%)) values from 5 to 12%, ensuring adequacy against the Association of Official Analytical Chemists guidelines. The method is robust against the following three influential factors considered in the cleanup stage: the batch of the graphitized carbon cartridges, the flow rate of the water sample through the cartridge, and the final redissolved water volume after SPE treatment. The method has been successfully applied to detection and quantification of CYN in water samples from aquaria of a toxicological in vivo laboratory experiment. Environ. Toxicol. Chem. 2012; 31: 2233-2238. ? 2012 SETAC.     

Phenolic composition and antioxidant capacity of bacaba-de-leque (Oenocarpus distichus Mart.) genotypes

Phenolic compound composition and antioxidant capacity of four Oenocarpus distichus Mart. (bacaba-de-leque) genotypes were determined. In order to set the parameters for phenolic compound extraction, the effect of methanol concentration and extraction time on the reducing power of the extracts was evaluated using the surface response methodology. The optimal conditions were: a 60:40 methanol:water (v/v) solution and 11 min of extraction. Extracts were analyzed by ultra-high performance liquid chromatography with diode array detection and by ultra-high performance liquid chromatography coupled to mass spectrometry. Eleven substances were identified, of which six were quantified. Rutin was the major compound in bacaba-de-leque genotypes (15.2–56.8 μg.g⁻¹) followed by epicatechin (15.5–21.2 μg.g⁻¹). The Black-03 genotype had the highest amounts of all phenolic compounds and the highest antioxidant capacity by DPPH and ORAC assays, indicating that this genotype may be selected in breeding programs to obtain cultivars with higher phenolic compound contents and antioxidant capacity. Moreover, the results indicated that bacaba-de-leque has great potential as a novel supplier of phenolic acids and flavonoids to human diet, with levels comparable to or higher than other fruits belonging to the same family, such as açaí.     

碳纳米管固相萃取-高效液相色谱法同时测定酱油和醋中四种尼泊金酯防腐剂

目的 建立酱油和醋中四种尼泊金酯防腐剂(尼泊金甲酯、尼泊金乙酯、尼泊金丙酯、尼泊金丁酯)的多壁碳纳米管固相萃取柱净化-高效液相色谱同时测定方法。方法 样品经碳纳米管净化后,高效液相色谱法分析。结果 方法线性范围上限至少为200mg/L,线性相关系数在0.999 7至0.999 9;方法检出限为0.090～0.120 mg/L,日内精密度为0.95%～2.51%,日间精密度为2.70%～5.76%。回收率范围为77.8%～99.2%。结论 本法样品处理方法简便、快速、重现性好、可用于批量样品中四种尼泊金酯类防腐剂的测定。     

Defatted milled grape seed protects adriamycin-treated hepatocytes against oxidative damage

Defatted milled grape seed (DMGS) is a wine by-product obtained from the oil extraction of the grape seed that contains different types of phenolic compounds. The present study was designed to evaluate the possible protective effect of DMGS on toxicity induced by adriamycin (ADR) in isolated rat hepatocytes. The study was carried out by examining the results of lactate dehydrogenase (LDH) release to estimate cytotoxicity; the thiobarbituric acid reactant substances (TBARS) and carbonyl group levels were measured as biomarkers of oxidative stress and ATP and GSH levels as estimation of intracellular effect. The results showed that DMGS extract protects the cellular membrane from oxidative damage and consequently prevents protein and lipid oxidation. The levels of ATP and GSH changes for the ADR toxicity were restored to control value in the presence of DMGS extract. The experimental results suggest that this wine by-product may be used to decrease oxidative stress.     

Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids

A strong radical-scavenging activity against a stable radical compound, 1,1-diphenyl-2-picrylhydrazyl (DPPH) was found in the hot water extract of Japanese rice bran. When the extract was treated with ethanol, a dominant radical-scavenging activity was observed in the ethanol-soluble (ES) fraction in a dose-dependent manner, but a weak radical-scavenging activity was detected in the ethanol-precipitable (EP) fraction. Their activities were proportional to the amounts of phenolic substances in each fraction. The phenolic substances in the ES fraction were efficiently separated by Amberlite XAD column chromatography and high performance liquid chromatography using an ODS column. The four major phenolic acids (ferulic, para-coumaric, para-hydroxybenzoic and vanillic acids) and four minor phenolic acids (caffeic, gentisic, protocatechuic and syringic acids) were detected in the HPLC system. Among these phenolic acids, protocatechuic, caffeic, ferulic and gentisic acids showed relatively strong radical scavenging activities (EC50: 8, 9, 29 and 75 microM, respectively) compared with the control antioxidants such as ascorbic acid and alpha-tocopherol (EC50: 93 and 134 microM). Para-coumaric, syringic and vanillic acids exhibited weak but significant radical-scavenging activities (EC50: 780, 2640 and 3250 microM). However, para-hydroxybenzoic acid did not show any significant effects even at 5 mM. Furthermore, a simulated mixture combined with these phenolic acids in comparable amounts in the ES fraction showed slightly weak radical-scavenging activity compared with that of rice bran extract. However, all the phenolic acids detected in the ES fraction did not show significant antioxidant activities against hydroperoxide generation in lipid peroxidation compared with that of a typical antioxidant such as ascorbic acid, which was estimated by the alminum chloride method. These results suggest that Japanese rice bran has a potent radical-scavenging activity against DPPH radical and this activity is associated with some phenolic acids in the ES fraction. The significance of this finding is discussed from the viewpoint of the protective role of rice bran against oxygen radical-induced chronic diseases.     

Assessment of phenolic compounds in biological samples

A short review of extraction, purification and cleanup procedures for the analysis of phenolic compounds (anthocyanins, flavonoids, catechins, phenolic acids, etc.) in animal and human biological fluids and organs is presented. The rising interest about the antioxidant capacity of these widespread constituents of fruit and vegetables enables these procedures an invaluable tool prior of the separation and identification of these compounds and their metabolites occurring in the organism. Finally, the usual chromatographic and spectrophotometric analytical techniques for their separation and identification are briefly summarized.     

Phytochemicals of foods, beverages and fruit vinegars: chemistry and health effects

Plant-based foods and food ingredients provide a wide range of phytochemicals and antioxidants that render their beneficial health effects through a number of mechanisms. The presence of phenolics in different plant materials and beverages depends on the source material which dictates the type and quantity present. In addition, processing of raw materials, including fermentation, may alter the chemical nature and efficacy of their phenolic constituents. While vinegar has traditionally been used for food preservation and as a seasoning, more recently, fruit vinegars with different sensory characteristics have appeared in the marketplace. In addition to acetic acid, fruit vinegars often contain citric, malic, lactic, and tartaric acids and may also include phenolics, some of which are produced as a result of fermentaion. The beneficial health effects of fruit vinegars may in part be related to the process-induced changes in their phenolics and generation of new antioxidative phenolics during fermentation.     

Evolution of Phenolic Compounds during Wine Fermentation and Post-fermentation: Influence of Grape Temperature

The evolution of different phenolic compounds during the first year of vinification of Monastrell wines as well as the influence of grape temperature at the moment of crushing on the quantitative composition and evolution of polyphenols were studied. Phenolic acids, hydroxycinnamic acid derivatives, anthocyanins, flavan-3-ols and flavonols were determined by HPLC. The results showed that temperature strongly influenced the rate of polyphenol extraction during the first three or four days of alcoholic fermentation but did so to a lesser degree as vinification progressed. At the end of the experiment, only caftaric and coutaric acids showed differences regarding the temperature of grapes at the moment of crushing.     

Discrimination of five Greek red grape varieties according to the anthocyanin and proanthocyanidin profiles of their skins and seeds

The knowledge of grapes phenolic content is proven to be critical for the vinification process and the improvement of wine quality. This study was undertaken to determine the phenolic composition and to employ the phenolic profile as a varietal discrimination tool in five Greek red grape varieties. Ninety grape samples from two seasons (2017 and 2018) were analyzed after extraction with organic solvents. Their proanthocyanidin profile, expressed as percentages of flavan-3-ols, was determined in both skins and seeds by employing phloroglucinolysis followed by HPLC-UV and MS detection, and anthocyanin profile was identified only in the skin extracts by HPLC-UV. Significant differences were observed in proanthocyanidin and anthocyanin profiles of skin extracts between the samples of different varieties, but not in seeds. (-)-Epicatechin was the main subunit in Mandilaria, Kotsifali, Agiorgitiko and Xinomavro grapes while (-)-epigallocatechin gallate in Mavrotragano. Malvidin-3-O-glucoside was the predominant pigment in all grape samples analyzed with the exception of Kotsifali skin extracts, where peonidin-3-O-glucoside was the most abundant anthocyanin. In addition, Mavrotragano skin extracts were the richest in delphinidin and petunidin-3-O-glucosides, while Agiorgitiko and Xinomavro contained the highest amount of malvidin-3-O-glucoside. The results underline the significance of the skin phenolic composition as a tool for the discrimination of the Greek red grape varieties.     

废水中阿维菌素的固相萃取-高效液相色谱测定法

目的 建立废水中阿维菌素含量的固相萃取-高效液相色谱测定法。方法 水样经Sep-Pak固相萃取柱分离净化后,以甲醇-水(95+5)为流动相,以10 ml的95％乙醇溶液作为洗脱液,在紫外检测器波长为244 nm处进行高效液相色谱进行测定。结果 在1～8 μg/ml的线性范围内,所得阿维菌素的回归方程为y=40006x-...     

酒中氨基甲酸乙酯的测定分析

目的建立酒中氨基甲酸乙酯含量的测定方法。方法以氘代同位素为内标,采用硅藻土固相萃取柱进行萃取,乙醚洗脱,气相色谱-质谱选择离子法测定。结果氨基甲酸乙酯的检出限为2.0μg/L,回收率为91.0%~102.0%,RSD为1.8%。采用本方法测定了河南市场上13种葡萄酒、25种白酒、12种黄酒、5种调料酒中氨基甲酸乙酯含量,结果为:葡萄酒3.5~246.4μg/kg、白酒6.9~485.5μg/kg、黄酒10.4~332.9μg/kg、调料酒24.9~49.1μg/kg。结论本方法精密度和准确度高,且简便快捷,适用于酒中氨基甲酸乙酯的测定。     

Grape Extract,Resveratrol, and Its Analogs: A Review

The recent and essential reports on the biological activity of the principal phytophenols of Vitis vinifera and wine, with special attention to resveratrol, are reviewed. The phytophenols are arbitrarily divisible into single-ring phenolic acids, bisphenols including stilbenes, tricyclic phenols (flavonoids) and their subclasses, and oligomeric and polymeric species, the proanthocyanidins and anthocyanidins. Their precursors and the stilbenes, including resveratrol with its analogs and conjugates, appear to be of preventative and possibly therapeutic value in atherosclerosis and certain neoplastic and inflammatory afflictions. The probable mechanisms are free radical scavenging and selective interference with a multitude of factors affecting the division cycle of rapidly and abnormally proliferating mammalian cells. Reviewed are studies of natural occurrence, extraction methods, bioavailability, analytical detection, and metabolism of resveratrol, as well as its effects on cancer and inflammation, atherosclerosis, and neurons. Because grape extracts are a convenient alimentary source of salutary phytochemicals to supplement currently prevalent occidental food and resveratrol appears to be especially useful, it could conveniently be added in biosignificant amounts to the grape extracts provided that their extraction, contents, and quality controls are instituted.