High-throughput method based on quick, easy, cheap, effective, rugged and safe followed by liquid chromatography-multi-wavelength detection for the quantification of multiclass polyphenols in wines

Preparation of imidazole-modified paper membrane for selective extraction of gallic acid and its structural and functional analogues from Pomegranate Peel

In the search for pharmaceutically active compounds from natural products, it is crucial and challenging to develop separation methods that target not only structurally similar compounds but also a class of compounds with desired pharmaceutical functions. To achieve both structure-oriented and function-oriented selectivity, the choice of functional monomers with broad interactions or even biomimetic roles towards targeted compounds is essential. In this work, an imidazole (IM)-functionalized paper membrane was synthesized to realize selectivity. The IM was selected based on its capability to provide multiple interactions, participation in several bioprocesses, and experimental verification of adsorption performance. Using gallic acid as a representative component of Pomegranate Peel, the preparation conditions and extraction parameters were systematically investigated. The optimal membrane solid-phase extraction (MSPE) method allowed for enrichment of gallic acid from the complex matrix of Pomegranate Peel, enabling facile quantitative analysis with a limit of detection (LOD) of 0.1 ng mL-1. Furthermore, with the aid of cheminformatics, the extracted compounds were found to be similar in both their structures and pharmaceutical functions. This work offers a novel approach to preparing a readily synthesized extraction membrane capable of isolating compounds with similar structures and pharmaceutical effects, and provides an MSPE-based analytical method for natural products.

Phenolic, Nutritional and Sensory Characteristics of Bakery Foods Formulated with Grape Pomace

The potentiality of cv. Malbec grape pomace (GP) as a functional ingredient in the formulation of bakery foods (muffins, biscuits and cereal bars) was studied. The effect of GP addition on the phenolic compounds (PCs) composition, nutritional and sensory properties were evaluated. The addition of GP increased the content of dietary fiber, proteins, ash, total phenolic content (TPC), antiradical capacity (AC), anthocyanins and non-anthocyanin PCs while decreasing the carbohydrates content. The main PCs given by the GP to supplemented foods were quercetin-3-O-glucoside, rutin, caffeic acid, syringic acid and (+)-catechin. For anthocyanins, the acylated derivatives were more stable to heat treatment (baking) in food processing which was evidenced by a higher proportion of these PCs compounds when compared to the same derivatives quantified in GP. In general, when the TPC or individual concentrations of PCs were analyzed in a nutritional or functional context, one portion of the supplemented foods showed levels high enough to satisfy the recommended dose per day of these bioactive compounds. Additionally, the foods were well received by consumers during the sensory evaluation and supplemented biscuits received the highest acceptability. This study demonstrated that GP could be a viable functional ingredient in bakery foods to incorporate components like PCs and dietary fiber into traditional consumers' diets.

A highly efficient strategy for simultaneous analysis of eleven monomeric hydroxylated-stilbenes in grape wines and juices by a salting-out assisted liquid-liquid (SALLE) extraction combined with a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)

Wine and grape juice are known to have hydroxylated stilbenes, a group of phytoalexins, health-promoting compounds. The determination of stilbene species in wine and grape juices remains a challenging task. Here, we propose an efficient strategy for the simultaneous determination of eleven hydroxylated stilbenes in grape wines and grape juice by a SALLE in conjunction with an HPLC-ESI-MS/MS. SALLE and HPLC-MS/MS conditions were optimized. The proposed method was validated and found to be a simple, sensitive, and reliable measure for the determination of the stilbene species in wine and grape juice. The SALLE was fast and efficient, taking only 10 min. The HPLC-MS/MS was able to quickly separate and quantitate the eleven stilbenes (9 min running). This method was successfully applied to determine the contents of stilbene species in commercial wine and grape juice in Korea. This method is advantageous in reduced sample preparation time, low labor, and cost efficiency.

Chemical Characterization and Bioactive Properties of Wine Lees and Diatomaceous Earth towards the Valorization of Underexploited Residues as Potential Cosmeceuticals

Annually, wine production is responsible for generating large quantities of residues, which are frequently disposed of and not valorized. So far, different studies have been conducted on grape pomace, yet less attention has been paid to other residues, such as wine lees and diatomaceous earth used in wine filtration. In this context, this study aimed to evaluate and compare the phenolic profile of these underexploited winemaking residues and assess their biological potential based on their antioxidant, antimicrobial, cytotoxic, and anti-aging activities (inhibition of tyrosinase and collagenase). Twenty-nine phenolic compounds, including twelve anthocyanins, were tentatively identified in the residues, with red grape pomace showing the highest diversity of compounds. The diatomaceous earth presented the highest content of non-anthocyanin phenolic compounds, being particularly rich in flavan-3-ols and myricetin-O-hexoside, and also presenting two anthocyanins. This sample also showed a high antioxidant activity, evidencing the best result in the reducing power assay. The red wine lees extract, despite showing a low content of phenolic compounds and less antioxidant activity, presented the highest inhibition capacity of bacteria growth. The extracts did not exhibit cytotoxicity against keratinocyte (up to 400 μg/mL) and fibroblast (up to 100 μg/mL) skin cell lines. However, the capacity of inhibiting tyrosinase and collagenase was low for the lees and diatomaceous earth, contrary to the grape pomace, seeds, and skins extracts that showed promising results, evidencing its potential as a cosmeceutical. Overall, this study highlights for the first time the potential of diatomaceous earth, an underexploited winemaking waste, in the obtention of added-value extracts and/or ingredients for cosmetic industry.

Easy fabrication of aminated graphene oxide functionalized magnetic nanocomposite for efficient preconcentration of phenolic acids prior to HPLC determination: Application in tea-derived wines

In this study, aminated graphene oxide functionalized magnetic nanocomposite (AGMN) was facilely synthesized by one-pot hydrothermal approach and acted as the extraction phase of magnetic solid phase extraction (MSPE) of phenolic acids (PAs). Characterization results revealed that the AGMN possessed satisfying saturation magnetism and abundant functional groups. Under the optimal extraction parameters, the proposed AGMN/MSPE presented high enrichment capability to PAs. Sensitive and dependable method for measurement of PAs in wine was proposed by the combination of AGMN/MSPE and HPLC/DAD. Limits of detection and limits of quantification were in the ranges of 0.031-0.23 μg/L and 0.10-0.78 μg/L, respectively, and the RSDs for approach precision varied from 1.8% to 8.9%. Recoveries at low, medium and high fortified levels varied from 84.6% to 116%. The suggested method was used to quantify investigated PAs in ten kinds of Tieguanyin tea-derived wines, and found the contents of PAs in wines were related to the quality of tea-leaves and alcohol content.

Antioxidant activity and development of one chromatographic method to determine the phenolic compounds from Agroindustrial Pomace

A chromatographic method consisting of multi wavelength detection for identification of six phenolic acids, one stilbene and five flavonoids in grape and apple pomaces was proposed. Scavenging of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), reactive oxygen species and reduction of Fe3+ to Fe2+ using in vitro and HPLC-UV-ABTS on-line methods are herein presented. A reversed phase C18 coupled with an absorption detector operating at 280, 300, 320 and 360 nm for the benzoic acid derivatives and flavanols; stilbenes; cinnamic acid derivatives and flavonols, were respecctively used. The solvents water, methanol and acetonitrile acidified with acetic acid were evaluated as mobile phase. The optimized chromatographic method presented recoveries ranged from 68 to 130% and from 66 to 130% for grape and apple pomaces respectively. The determination coefficients (R2) of the 12 compounds were > 0.98. The extracts showed high total phenolic content and exhibits strong capacities to scavenge free radicals and reactive oxygen species. The results obtained by HPLC-ABTS on-line method suggest that pomaces of grape and apple are rich in bioactive compounds and that catechin and epicatechin contribute in a significantly way to the antioxidant activity in both agroindustrial pomaces.

Organic Acids and Polyphenols Determination in Polish Wines by Ultrasound-Assisted Solvent Extraction of Porous Membrane-Packed Liquid Samples

In the near future, Poland is going to have more and more favorable conditions for viticulture. Organic acids and polyphenols are among the most commonly analyzed compounds due to their beneficial properties for human health and their importance in the winemaking process. In this work, a new technique involving ultrasound-assisted solvent extraction of porous membrane-packed liquid samples (UASE-PMLS) was for the first time described and applied for real samples. The methodology based on UASE-PMLS for organic acids and polyphenols in wine samples was optimized and validated. Using the new technique coupled to GC–MS, organic acids and polyphenols were evaluated in Polish wine samples. Extraction solvent, extraction temperature, derivatization time and sample pH were optimized. Chemometric tools were used for data treatment. Good linearity was obtained for the concentration ranges evaluated with r values between 0.9852 and 0.9993. All parameters of method validation (intra- and inter-day precision and matrix effect) were over 80% with coefficient of variation (CV) up to 17%. Recovery was between (92.0 ± 8.5)% and (113 ± 16)%. Finally, green assessment was evaluated using Analytical Eco-Scale and Green Analytical Procedure Index (GAPI). The UASE-PMLS is characterized by many advantages, e.g., the extraction process is fast and easy coupled to GC–MS. Regarding other extraction techniques, the amount of used solvent is minimum, and no waste is generated. Therefore, it is an environmentally friendly technique.

A Triple Quadrupole and a Hybrid Quadrupole Orbitrap Mass Spectrometer in Comparison for Polyphenol Quantitation

Liquid chromatography coupled to low-resolution mass spectrometry (LRMS) has historically been a popular approach for compound quantitation. Recently, high-resolution mass spectrometry (HRMS) technical developments led to the introduction of new approaches for quantitative analysis. Whereas the performances of HRMS have been largely assessed for qualitative purposes, there are still questions about its suitability for quantitative analysis. Several papers on LRMS and HRMS comparison have been published; however, none of them was applied to polyphenol quantitation. In this work, a comparison between HRMS, operated in data-dependent acquisition mode, and LRMS, operated in selected-reaction-monitoring mode, was performed for polyphenol quantitation in wine. The two techniques were evaluated in terms of sensitivity, linearity range, matrix effect, and precision, showing the better performances of HRMS. The suitability of HRMS for quantitation purposes as well as qualitative screening makes HRMS the new technique of choice for both targeted and untargeted analysis.

Are polyphenol antioxidants at the root of medicinal plant anti-cancer success?

ETHNOPHARMACOLOGICAL RELEVANCE

Given the severe side effects associated with most of the conventional cancer medications, as well as the expanding body of evidence indicating secondary toxicity of these drugs, individuals with cancer are increasingly turning to natural alternatives. Similarly, the pharmaceutical industry is in search of natural products to treat cancer. An understanding of the specific active components in plant products with which anti-cancer efficacy is achieved is required for this research to move forward.

AIM OF THE STUDY

To integrate data from cancer-relatestudies on plant-derived products or extracts, to elucidate whether these products may have similar active ingredients and/or mechanisms of action, that can explain their efficacy. This review also includes a discussion of the methodological complexities and important considerations involved in accurate isolation and characterisation of active substances from plant material.

CONCLUSIONS

From the literature reviewed, most plant products with consistently reported anti-cancer efficacy contains high levels of polyphenols or other potent antioxidants and their mechanisms of action correlate to that reported for isolated antioxidants in the context of cancer. This suggests that natural products may indeed become the panacea against this chronic disease - either as therapeutic medicine strategy or to serve as templates for the design of novel synthetic drugs. The recommendation is made that antioxidant activity of plant actives and especially polyphenols, should be the focus of anti-cancer drug discovery initiatives. Lastly, researchers are advised to exploit current techniques of chemical compound characterisation when investigating polyphenol-rich plants to enable the easy consolidation of research findings from different laboratories.

UPLC-MS/MS analysis of ochratoxin A metabolites produced by Caco-2 and HepG2 cells in a co-culture system

Ochatoxin A (OTA) is one of the most important mycotoxins based on its toxicity. The oral route is the main gateway of entry of OTA into the human body, and specialized epithelial cells constitute the first barrier. The present study investigated the in vitro cytotoxic effect of OTA (5, 15 and 45 μM) and production of OTA metabolities in Caco-2 and HepG2 cells using a co-culture Transwell System to mimic the passage through the intestinal epithelium and hepatic metabolism. The results derived from MTS cell viability assays and transepithelial electrical resistance measurements showed that OTA was slightly cytotoxic at the lowest concentration at 3 h, but significant toxicity was observed at all concentrations at 24 h. OTA metabolites generated in this co-culture were ochratoxin B (OTB), OTA methyl ester, OTA ethyl ester and the OTA glutathione conjugate (OTA-GSH). OTA methyl ester was the major metabolite found in both Caco-2 and HepG2 cells after all treatments. Our results showed that OTA can cause cell damage through several mechanisms and that the OTA exposure time is more important that the dosage in in vitro studies. OTA methyl ester is proposed as an OTA exposure biomarker, although future studies should be conducted.

Effective synthesis of magnetic porous molecularly imprinted polymers for efficient and selective extraction of cinnamic acid from apple juices

An effective strategy was proposed to prepare novel magnetic porous molecularly imprinted polymers (MPMIPs) for highly selective extraction of cinnamic acid (CMA) from complex matrices. Characterization and various parameters affecting adsorption and desorption behaviors were investigated. Results revealed adsorption behavior between CMA and MPMIPs followed Freundlich equation adsorption isotherm with a maximum adsorption capacity at 4.35mg/g and pseudo-second-order reaction kinetics with equilibrium time at 60min. Subsequently, MPMIPs were successfully used to selectively extract CMA from apple juice with a relatively satisfactory recovery (92.7-101.4%). Coupling with high-performance liquid chromatography and ultraviolet detection (HPLC-UV), the limit of detection (LOD) for CMA was 0.006µg/mL, and the linear range (0.02-10μg/mL) was wide with correlation coefficient at 0.9995. Finally, the contents of CMA in two kinds of apple juices were determined as 0.132 and 0.120μg/mL. Results indicated the superiority of MPMIPs in the selective extraction field.

Grape pomace reduced reperfusion arrhythmias in rats with a high-fat-fructose diet

Metabolic syndrome (MetS) is a risk factor of sudden cardiac death. GP containing bioactive compounds prevents/attenuates MetS-associated cardiovascular pathologies.

Front-face fluorescence spectroscopy combined with second-order multivariate algorithms for the quantification of polyphenols in red wine samples

The potential of front-face fluorescence spectroscopy combined with second-order chemometric methods was investigated for the quantification of the main polyphenols present in wine samples. Parallel factor analysis (PARAFAC) and unfolded-partial least squares coupled to residual bilinearization (U-PLS/RBL) were assessed for the quantification of catechin, epicatechin, quercetin, resveratrol, caffeic acid, gallic acid, p-coumaric acid, and vanillic acid in red wines. Excitation-emission matrices of different red wine samples, without pretreatment, were obtained in front-face mode, recording emission between 290 and 450 nm, exciting between 240 and 290 nm, for the analysis of epicatechin, catechin, caffeic acid, gallic acid, and vanillic acid; and excitation and emission between 300-360 and 330-400nm, respectively, for the analysis of resveratrol. U-PLS/RBL algorithm provided the best results and this methodology was validated by an optimized liquid chromatographic coupled to diode array and fluorimetric detectors procedure, obtaining a very good correlation for vanillic acid, caffeic acid, epicatechin and resveratrol.

Grape pomace and grape pomace extract improve insulin signaling in high-fat-fructose fed rat-induced metabolic syndrome

In this study the effect of diet supplementation with grape pomace (GP) and grape pomace extract (GPE) on insulin sensitive tissues (adipose, liver and muscle) was evaluated in an experimental model of metabolic syndrome (MetS).