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Citrus processing side-streams are largely represented by waste orange peels (WOP), and there are several techniques developed for polyphenol extraction from WOP; yet, there are a significant lack of methodologies based on non-conventional, green solvents. On this basis, this study was performed to assess a deep eutectic solvent (DES) synthesized with glycerol and sodium butyrate, for its capacity to extract WOP polyphenols. Optimization of the process was carried out using a response surface methodology, which revealed that a maximum total polyphenol yield of 73.36 mg gallic acid equivalent (GAE) g−1 dry mass (DM) could be achieved with a solvent system of DES/water (80% w/w), a residence time of 120 min, and a temperature of 90 °C. Using these settings, the polyphenol extraction from WOP with the DES/water solvent system was found to have outstanding performance compared to aqueous or hydroethanolic extraction, while the extracts generated possessed significantly enhanced antioxidant properties. The chromatographic analyses of the extracts demonstrated that the DES/water extract was particularly enriched in hesperidin (21.81 mg g−1 dry mass), a bioflavonoid with promising pharmaceutical potential. This is a first report on the use of this particular DES for WOP polyphenol extraction, which may be used to produce hesperidin-enriched extracts, by implementing the methodology developed. [ABSTRACT FROM AUTHOR]

In dead biological tissues such as human hair, the ability of antioxidants to minimise autoxidation is determined by their chemical reactions with reactive oxygen species. In order to improve our understanding of factors determining such antioxidant properties, the mechanistic chemistry of four phenolic antioxidants found in tea and rosemary extracts (epicatechin, epigallocatechin gallate, rosmarinic and carnosic acids) has been investigated. The degradation of N-acetyl alanine by photochemically generated hydroxyl radicals was used as a model system. A relatively high concentration of the antioxidants (0.1 equivalent with respect to the substrate) tested the ability of the antioxidants to intercept both initiating hydroxyl radicals (preventive action) and propagating peroxyl radicals (chain-breaking action). LC-MS data showed the formation of hydroxylated derivatives, quinones and hydroperoxides of the antioxidants. The structure of the assignment was aided by deuterium exchange experiments. Tea polyphenolics (epicatechin and epigallocatechin gallate) outperformed the rosemary compounds in preventing substrate degradation and were particularly effective in capturing the initiating radicals. Carnosic acid was suggested to act mostly as a chain-breaking antioxidant. All of the antioxidants except for rosmarinic acid generated hydroperoxides which was tentatively ascribed to the insufficient lability of the benzylic C-H bond of rosmarinic acid. [ABSTRACT FROM AUTHOR]

A response surface methodology (RSM) with a central composite design (CCD) was developed to predict and apply the best ultrasound-assisted extraction (UAE) conditions, including the extraction time, the composition of aqueous-ethanolic extractants, and the solvent-to-plant-material ratio, for obtaining the highest yields of different types of polyphenolic components from the dried flower buds of Magnolia × soulangeana Soul.-Bod. var. 'Lennei' (MSL). The novel approach in the RSM procedure resulted from the simultaneous optimisation of UAE conditions to obtain extracts with the highest antioxidant and antiradical potential (examined as dependent variables), using appropriate spectrophotometric assays, with Folin–Ciocâlteu and 2,2-diphenyl-1-picrylhydrazyl reagents, respectively. The use of 66.8% (V/V) ethanol as the extraction solvent during the 55.2 min extraction protocol and the ratio of extractant volume to herbal substance of 46.8 mL/g gave the highest total yield of bioactive antioxidant phenolics in the extract obtained. For this herbal preparation, a qualitative and quantitative analysis was performed using combined chromatographic (LC), spectroscopic (PDA), and tandem mass spectrometric (ESI-QToF–MS/MS) techniques. A detailed phytochemical profiling, conducted for the first time, documented substantial amounts of various polyphenolic antioxidants, especially phenylethanoids and flavonoids, in the MSL flower buds. Their average total content exceeded 30.3 and 36.5 mg/g dry weight, respectively. [ABSTRACT FROM AUTHOR]

Citrus processing side-streams are largely represented by waste orange peels (WOP), and there are several techniques developed for polyphenol extraction from WOP; yet, there are a significant lack of methodologies based on non-conventional, green solvents. On this basis, this study was performed to assess a deep eutectic solvent (DES) synthesized with glycerol and sodium butyrate, for its capacity to extract WOP polyphenols. Optimization of the process was carried out using a response surface methodology, which revealed that a maximum total polyphenol yield of 73.36 mg gallic acid equivalent (GAE) g−1 dry mass (DM) could be achieved with a solvent system of DES/water (80% w/w), a residence time of 120 min, and a temperature of 90 °C. Using these settings, the polyphenol extraction from WOP with the DES/water solvent system was found to have outstanding performance compared to aqueous or hydroethanolic extraction, while the extracts generated possessed significantly enhanced antioxidant properties. The chromatographic analyses of the extracts demonstrated that the DES/water extract was particularly enriched in hesperidin (21.81 mg g−1 dry mass), a bioflavonoid with promising pharmaceutical potential. This is a first report on the use of this particular DES for WOP polyphenol extraction, which may be used to produce hesperidin-enriched extracts, by implementing the methodology developed.

Crop domestication has resulted in nutrient losses, so evaluating the reshaping of phytonutrients is crucial for improving nutrition. Soybean is an ideal model due to its abundant phytonutrients and wild relatives. In order to unravel the domestication consequence of phytonutrients, comparative and association analyses of metabolomes and antioxidant activities were performed on seeds of six wild (Glycine soja (Sieb. and Zucc.)) and six cultivated soybeans (Glycine max (L.) Merr.). Through ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS), we observed a greater metabolic diversity in wild soybeans, which also displayed higher antioxidant activities. (−)-Epicatechin, a potent antioxidant, displayed a 1750-fold greater abundance in wild soybeans than in cultivated soybeans. Multiple polyphenols in the catechin biosynthesis pathway were significantly higher in wild soybeans, including phlorizin, taxifolin, quercetin 3-O-galactoside, cyanidin 3-O-glucoside, (+)-catechin, (−)-epiafzelechin, catechin–glucoside, and three proanthocyanidins. They showed significant positive correlations with each other and antioxidant activities, indicating their cooperative contribution to the high antioxidant activities of wild soybeans. Additionally, natural acylation related to functional properties was characterized in a diverse range of polyphenols. Our study reveals the comprehensive reprogramming of polyphenolic antioxidants during domestication, providing valuable insights for metabolism-assisted fortification of crop nutrition. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the polyphenolic composition of Deschampsia antarctica È. Desv. plants grown at natural conditions on different locations on the Galindez Island, Argentine Islands, the maritime Antarctic. The plants were collected during the summer season of the 26th Ukrainian Antarctic Expedition (2020–2022). The extracts of 21 plants were obtained and the composition of the extracts was analyzed by means of high-performance liquid chromatography and matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant properties of the extracts were characterized using the DPPH (2,2-diphenyl-1-picrylhydrazyl) test. The extracts were found to contain large amount of polyphenolic compounds, with flavonoids and phenolic acids, as well as their derivatives, being the most common classes of the phenols. Using the HPLC data the content of various phenols in the plants was systematic studied. It has been found that in all plants the most abundant phenols are flavonoids/flavonoid derivatives (on average about 75% of total mass of phenols). Among the flavonoids, luteolin derivatives predominate (86–94% of the total mass of flavonoids), and, among luteolin derivatives, the main compounds are orientin, orientin 2"- O-β-arabinopyranoside and isoswertiajaponin 2"- O-β-arabinopyranoside (67–83% of the total mass of luteolin derivatives). It has been also found that all the extracts possess the high activity in inhibition of DPPH radicals and that the antioxidant activity of the extracts correlates with total content of phenols in the samples. Thus, Deschampsia antarctica É. Desv. plants are a valuable source of natural phenolic antioxidants, and the most common antioxidants in the extracts are orientin, orientin 2"- O-β-arabinopyranoside and isoswertiajaponin 2"- O-β-arabinopyranoside.

In dead biological tissues such as human hair, the ability of antioxidants to minimise autoxidation is determined by their chemical reactions with reactive oxygen species. In order to improve our understanding of factors determining such antioxidant properties, the mechanistic chemistry of four phenolic antioxidants found in tea and rosemary extracts (epicatechin, epigallocatechin gallate, rosmarinic and carnosic acids) has been investigated. The degradation of N-acetyl alanine by photochemically generated hydroxyl radicals was used as a model system. A relatively high concentration of the antioxidants (0.1 equivalent with respect to the substrate) tested the ability of the antioxidants to intercept both initiating hydroxyl radicals (preventive action) and propagating peroxyl radicals (chain-breaking action). LC-MS data showed the formation of hydroxylated derivatives, quinones and hydroperoxides of the antioxidants. The structure of the assignment was aided by deuterium exchange experiments. Tea polyphenolics (epicatechin and epigallocatechin gallate) outperformed the rosemary compounds in preventing substrate degradation and were particularly effective in capturing the initiating radicals. Carnosic acid was suggested to act mostly as a chain-breaking antioxidant. All of the antioxidants except for rosmarinic acid generated hydroperoxides which was tentatively ascribed to the insufficient lability of the benzylic C-H bond of rosmarinic acid.

The aim of this work was to study the polyphenolic composition of Deschampsia antarctica È. Desv. plants grown in natural conditions at different locations on the Galindez Island, Argentine Islands, the maritime Antarctic. The plants were collected during the summer season of the 26th Ukrainian Antarctic Expedition (2020-2022). The extracts of 21 plants were obtained and the composition of the extracts was analyzed by means of highperformance liquid chromatography and matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant properties of the extracts were characterized using the DPPH (2,2-diphenyl-1-picrylhydrazyl) test. The extracts contained large amount of polyphenolic compounds, with flavonoids and phenolic acids, as well as their derivatives, being the most plants was systematic studied. It has been found that in all plants the most abundant phenols were flavonoids/flavonoid derivatives (on average about 75% of total mass of phenols). Among the flavonoids, luteolin derivatives predominated (86-94% of the total mass of flavonoids), and, among luteolin derivatives, the main compounds were orientin, orientin 2"-O-ß-arabinopyranoside and isoswertiajaponin 2"-O-ß-arabinopyranoside (67-83% of the total mass of luteolin derivatives). It has been also found that all the extracts had high activity in inhibition of DPPH radicals and that the antioxidant activity of the extracts correlated with total content of phenols in the samples. Thus, Deschampsia antarctica É. Desv. plants are a valuable source of natural phenolic antioxidants, and the most common antioxidants in the extracts are orientin, orientin 2"-O-ß-arabinopyranoside and isoswertiajaponin 2"-O-ß-arabinopyranoside. [ABSTRACT FROM AUTHOR]

A response surface methodology (RSM) with a central composite design (CCD) was developed to predict and apply the best ultrasound-assisted extraction (UAE) conditions, including the extraction time, the composition of aqueous-ethanolic extractants, and the solvent-to-plant-material ratio, for obtaining the highest yields of different types of polyphenolic components from the dried flower buds of Magnolia × soulangeana Soul.-Bod. var. ‘Lennei’ (MSL). The novel approach in the RSM procedure resulted from the simultaneous optimisation of UAE conditions to obtain extracts with the highest antioxidant and antiradical potential (examined as dependent variables), using appropriate spectrophotometric assays, with Folin–Ciocâlteu and 2,2-diphenyl-1-picrylhydrazyl reagents, respectively. The use of 66.8% (V/V) ethanol as the extraction solvent during the 55.2 min extraction protocol and the ratio of extractant volume to herbal substance of 46.8 mL/g gave the highest total yield of bioactive antioxidant phenolics in the extract obtained. For this herbal preparation, a qualitative and quantitative analysis was performed using combined chromatographic (LC), spectroscopic (PDA), and tandem mass spectrometric (ESI-QToF–MS/MS) techniques. A detailed phytochemical profiling, conducted for the first time, documented substantial amounts of various polyphenolic antioxidants, especially phenylethanoids and flavonoids, in the MSL flower buds. Their average total content exceeded 30.3 and 36.5 mg/g dry weight, respectively.

Crop domestication has resulted in nutrient losses, so evaluating the reshaping of phytonutrients is crucial for improving nutrition. Soybean is an ideal model due to its abundant phytonutrients and wild relatives. In order to unravel the domestication consequence of phytonutrients, comparative and association analyses of metabolomes and antioxidant activities were performed on seeds of six wild (Glycine soja (Sieb. and Zucc.)) and six cultivated soybeans (Glycine max (L.) Merr.). Through ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS), we observed a greater metabolic diversity in wild soybeans, which also displayed higher antioxidant activities. (−)-Epicatechin, a potent antioxidant, displayed a 1750-fold greater abundance in wild soybeans than in cultivated soybeans. Multiple polyphenols in the catechin biosynthesis pathway were significantly higher in wild soybeans, including phlorizin, taxifolin, quercetin 3-O-galactoside, cyanidin 3-O-glucoside, (+)-catechin, (−)-epiafzelechin, catechin–glucoside, and three proanthocyanidins. They showed significant positive correlations with each other and antioxidant activities, indicating their cooperative contribution to the high antioxidant activities of wild soybeans. Additionally, natural acylation related to functional properties was characterized in a diverse range of polyphenols. Our study reveals the comprehensive reprogramming of polyphenolic antioxidants during domestication, providing valuable insights for metabolism-assisted fortification of crop nutrition.

Abstract Background Microbial fuel cells (MFCs) are effective biofuel devices that use indigenous microbes to directly convert chemical energy from organics oxidation into bioelectric energy. To maximize energy-converting efficiency for bioelectricity generation in MFCs, redox mediators (RMs) (e.g., extracts obtained from plant resource-Camellia green tea) have been explored for optimal stimulation upon electron transfer (ET) capabilities. Anthocyanins are natural antioxidants widely used in food science and medicinal industry. This first-attempt study revealed optimal strategies to augment extracts of anthocyanin-rich herbs (Lycium ruthenicum Murr., Clitoria ternatea Linn. and Vaccinium Spp.) as biofuel sources of catalytic RMs for stimulating bioenergy extraction in MFCs. Results This work showed that extracts of anthocyanin-rich herbs were promising electroactive RMs. The maximal power density of MFCs supplemented with extract of L. ruthenicum Murr. was achieved, suggesting that extract of L. ruthenicum Murr. would be the most electrochemically appropriate RMs. Compared to C. ternatea Linn. and Vaccinium Spp., L. ruthenicum Murr. evidently owned the most significant redox-mediating capability to stimulate bioenergy extraction likely due to significantly high contents of polyphenols (e.g., anthocyanin). Evidently, increases in adenosine triphosphate (ATP) content directly responded to supplementation of anthocyanin-rich herbal extracts. It strongly suggested that the electron-shuttling characteristics of RMs upon electroactive microorganisms could effectively promote the electron transfer capability to maximize bioenergy extraction in MFCs. Conclusion Anthocyanin as the main water-soluble vacuolar pigments in plant products were very electroactive for not only excellent antioxidant activities, but also promising electron-shuttling capabilities for renewable biofuel applications. This work also suggested the electron-shuttling mechanism of RMs that could possibly promote electron transport phenomena through microbial cell membrane, further influencing the electron transport chain for efficient bioenergy generation.

Objectives: Direct scavenging of reactive oxygen species could not prevent ER stress‐associated cytotoxicity of indomethacin or diclofenac in Caco‐2 cells. This study investigated the effects of three polyphenolic antioxidants epigallocatechin gallate (EGCG), phyllanthin and hypophyllathin in non‐steroidal anti‐inflammatory drug‐induced Caco‐2 apoptosis. Methods: Cells were treated with ER stressors (indomethacin, diclofenac, tunicamycin or thapsigargin) and the polyphenols for up to 72 h. Cell viability, apoptosis and mitochondrial function were monitored by MTT, Hoechst 33342 and TMRE assays, respectively. Protein expression was measured by Western blot analysis. Key findings: Epigallocatechin gallate suppressed increases in p‐PERK/p‐eIF‐2α/ATF‐4/CHOP and p‐IRE‐1α/p‐JNK1/2 expression levels in the cells treated with any of the ER stressors, leading to inhibition of apoptosis. In contrast, phyllanthin increased apoptosis in the cells subsequently exposed to either diclofenac, tunicamycin or thapsigargin, but not in the indomethacin‐treated cells. The potentiation effect of phyllanthin seen with the three ER stressors was related to suppression of survival p‐Nrf‐2/HO‐1 expression, resulting in increased activation of the eIF‐2α/ATF‐4/CHOP pathway. On the other hand, hypophyllanthin had no significant effect on the ER stressor‐induced apoptosis. Conclusion: Epigallocatechin gallate, phyllanthin and hypophyllanthin displayed different effects in the ER stress‐mediated apoptosis, depending upon their interaction with the specific unfolded protein response signalling. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the nephroprotective and cardioprotective effects of ethanol extract of litchi leaf (LI) in two-kidney-one-clip (2K1C) rat model. HPLC analysis revealed the presence of several polyphenolic antioxidants in LI. Correspondingly, LI at 50–200 mg/kg reduced the level of oxidative stress markers (MDA, APOP, NO) and improved level of endogenous antioxidant enzymes (CAT, SOD) in 2K1C rats. Besides, LI caused significant improvements in kidney and heart functions in 2K1C rats by reducing the plasma level of uric acid and creatinine as well as CK-MB. Consistent with the biochemical findings, histopathological data further confirmed that LI is effective in decreasing heart and kidney injuries, oxidative stress and inflammation which ensued in 2K1C rats. Collectively, the outcomes suggest that the LI enriched in polyphenolic antioxidants may provide the protection against excessive oxidative stress, inflammation and tissue injury, thereby improving the kidney and heart function in 2K1C rats.

Introduction Functional food plays an important role in the prevention, management and treatment of chronic diseases. One of the most interesting techniques of functional food production is extrusion-cooking. Functional foods may include such items as puffed cereals, breads and beverages that are fortified with vitamins, some nutraceuticals and herbs. Due to its pharmacological activity, chamomile flowers are the most popular components added to functional food. Objective. Quantitative analysis of polyphenolic antioxidants, as well as comparison of various methods for the extraction of phenolic compounds from corn puffed cereals, puffed cereals with an addition of chamomile (3, 5, 10 and 20%) and from Chamomillae anthodium. Material and Methods Two modern extraction methods – ultrasound assisted extraction (UAE) at 40oC and 60oC, as well as accelerated solvent extraction (ASE) at 100oC and 120oC were used for the isolation of polyphenols from functional food. Analysis of flavonoids and phenolic acids was carried out using reversed-phase high-performance liquid chromatography and electrospray ionization mass spectrometry (LC-ESI-MS/MS). Results and Conclusions For most of the analyzed compounds, the highest yields were obtained by ultrasound assisted extraction. The highest temperature during the ultrasonification process (60oC) increased the efficiency of extraction, without degradation of polyphenols. UAE easily arrives at extraction equilibrium and therefore permits shorter periods of time, reducing the energy input. Furthermore, UAE meets the requirements of ‘Green Chemistry’

Increasing interest in production of frequently consumed functional food products has focused the present study on implementation of microencapsulated Ganoderma mushroom and green tea bioactive compounds in beer production. Electrostatic extrusion assisted microencapsulation of green tea and Ganoderma extracts enabled production of particles ranging from 490 to 1000 μm in size, with up to 75% of entrapped total polyphenols. Dried, powdered extracts, as well as microparticles encapsulating Ganoderma and green tea extracts that exhibited the best morphological properties and retarded release of polyphenols (alginate and alginate-chitosan coated, as well as chitosan coated pectin microbeads) were implemented in beer production. The addition of Ganoderma microbeads to pilsner beer did not augment its polyphenolic concentration (TPC), as opposed to the addition of green tea encapsulating microbeads to radler, while adding dried Ganoderma and spray dried green tea extracts enabled to increase the TPC for up to 3-fold higher values. Ganoderma dried extract-enriched pilsner beer and spray dried green tea extract-enriched radler were preferred in terms of sensory properties, due to the lowest bitterness intensity and most pronounced herbal aroma of the added adjuncts. Refrigerated storage of Ganoderma hydrogel microbeads-enriched pilsner beer revealed fluctuations of TPC, while green tea hydrogel microbeads-enriched radler exhibited better stability. The established methodology provides a procedure suitable for microencapsulate-enrichment of drink and food products, thus setting a reliable basis for future functional food production by microencapsulate implementation strategies. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46001, Grant no. 46010 and Grant no. 31020]

Abstract This first-attempt study revealed optimal strategy to supplement extracts of polyphenolics-abundant medicinal herbs and Camellia tea as electron shuttles (ESs) for stimulating bioenergy generation in microbial fuel cells (MFCs). Apparently, Camellia sinensis (L.) Kuntze and Syzygium aromaticum were promising electroactive ESs. Moderate temperature (ca. 65 °C) and slightly alkali pHs (∼10) were electrochemically feasible conditions for herbal extraction. Optimal contents of polyphenolics-rich herbs and tea extracts with maximal electrochemical activities could be stably obtained. Power density of MFC supplemented with Camellia green tea extract could significantly increase ca. 176%, suggesting that green tea extract would be the most appropriate ESs. Total phenolic contents and electron shuttling capabilities were all electrochemically associated. In addition, chemical structure strongly affected whether antioxidant activities of polyphenolics-abundant herbal extracts could be reversibly switched to be electron-shuttling capabilities (e.g., substitution patterns). Hydroxyl substiutuents ortho or para to each other were very likely promising for electron-shuttling, but not for meta substituents. Moreover, bioelectrochemical treatment upon medicinal herbal extracts (e.g., cyclic electron-donating and withdrawing processes) might be inevitably needed for toxicity attenuation to fully express bioenergy-shuttling activities. Highlights • Unveil natural electron shuttles (ESs) from herbal and tea extracts for MFCs. • Disclose operation strategy to convert polyphenolic antioxidants to be ESs. • Decipher biostimulation of natural ES catalysts to power generation in MFCs. [ABSTRACT FROM AUTHOR]

This first-attempt study used extracts of appropriate antioxidant abundant Camellia and non- Camellia tea and medicinal herbs as model ESs to stably intensify bioelectricity generation performance in microbial fuel cells (MFCs). As electron shuttles (ESs) could stimulate electron transport phenomena by significant reduction of electron transfer resistance, the efficiency of power generation for energy extraction in microbial fuel cells (MFCs) could be appreciably augmented. Using environmentally friendly natural bioresource as green bioresource of ESs is the most promising to sustainable practicability. As comparison of power-density profiles indicated, supplement of Camellia tea extracts would be the most appropriate, then followed non- Camellia Chrysanthemum tea and medicinal herbs. Antioxidant activities, total phenolic contents and power stimulating activities were all electrochemically associated. In particular, the extract of unfermented Camellia tea (i.e., green tea) was the most promising ESs to augment bioenergy extraction compared to other refreshing medicinal herb extracts. [ABSTRACT FROM AUTHOR]

Novel methods for the determination of polyphenolic antioxidants present in extracts from inflorescences of Cirsium vulgare (Savi) Ten. based on ultra-high performance liquid chromatography with photodiode array and chemiluminescence detection have been developed. Under the optimized conditions of chromatographic separation the analytical characteristic of the method was performed. The proposed method was successfully applied to the determination of ten polyphenols present in inflorescences of Cirsium vulgare. A comparison of the contents of analytes in extracts prepared by using various extraction media (methanol, ethanol, 70% methanol, 70% ethanol, and water) was carried out for the first time. For the postcolumn detection of scavenging activity of polyphenolic antioxidants against reactive oxygen species (H2O2, •OH, O2• −) three systems based on chemiluminescence of luminol were used. A review of the current scientific literature shows that this is the first report on the application of luminol-based postcolumn detection for the on-line investigation of •OH scavenging activity. The main compound determined in extracts from inflorescences of Cirsium vulgare was apigenin 7-O-glucuronide, whereas the highest antioxidant activity was observed for chlorogenic acid, luteolin 7-O-glucoside, and apigenin. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new theoretical model, B D E η W is proposed for estimating phenolic O H bond dissociation enthalpy (BDE). • Calculation of B D E η W involves lesser computational effort as compared to those involve in conventional BDE calculations. • BDE η W reproduces experimental and calculated CBS-QB3 results with high accuracy. • Role of hydrogen bond energy in explaining O H BDE is revisited. The importance of hydrogen atom transfer (HAT) reaction has been realized in various fields, ranging from atmospheric chemistry to biological processes. HAT is noteworthy in exploring phenolic antioxidants as these molecules scavenge harmful reactive free radicals through this popular pathway. The determining index of the HAT reaction is the bond dissociation enthalpy (BDE). This article proposes a theoretical model for estimating the O H BDE, a key concept for assessing HAT reactions. The model is shown to have high accuracy, and is computationally cheaper than the conventional methods of computing BDE. It has been tested with 35 polyphenolic systems having antioxidant activity involved through the HAT mechanism. Further, topological parameters within the QTAIM are computed along with the hydrogen bond energies to understand the intramolecular hydrogen bonding in such polyphenolic systems undergoing HAT reactions. [ABSTRACT FROM AUTHOR]

Berberis jaeschkeana fruits, source of nutraceutically important polyphenolics were investigated. A total of 32 experimental run were conducted under Plackett-Burman and central composite design. Microwave power, methanol and HCl concentration significantly (p < 0.05) affect extraction of polyphenols under linear, quadratic and interactive effect. The model showed good fitness with significant (p < 0.05) model F-value and a non-significant lack of fit. Under optimum microwave assisted extraction (MAE) condition the total phenolics, flavonoids, tannins and antioxidant activity were in closed context with predicted values. As compared to ultrasonic (UAE) and maceration extraction (ME), MAE showed significantly (p < 0.05) higher recovery of TP, TF and FRAP antioxidant activity. HPLC-DAD analysis detects a total of 10 polyphenolic compounds under MAE as compared to 9 under UAE and ME. Designing of MAE conditions showed promising results for polyphenolic antioxidants extraction as revealed by higher yield with lesser time and solvent consumption, which can contribute in green extraction technology and its application in nutraceutical industry. [ABSTRACT FROM AUTHOR]

Introduction. Functional food plays an important role in the prevention, management and treatment of chronic diseases. One of the most interesting techniques of functional food production is extrusion-cooking. Functional foods may include such items as puffed cereals, breads and beverages that are fortified with vitamins, some nutraceuticals and herbs. Due to its pharmacological activity, chamomile flowers are the most popular components added to functional food. Objective. Quantitative analysis of polyphenolic antioxidants, as well as comparison of various methods for the extraction of phenolic compounds from corn puffed cereals, puffed cereals with an addition of chamomile (3, 5, 10 and 20%) and from Chamomillae anthodium. Materials and Methods. Two modern extraction methods - ultrasound assisted extraction (UAE) at 40 °C and 60 °C, as well as accelerated solvent extraction (ASE) at 100 °C and 120 °C were used for the isolation of polyphenols from functional food. Analysis of flavonoids and phenolic acids was carried out using reversed-phase high-performance liquid chromatography and electrospray ionization mass spectrometry (LC-ESI-MS/MS). Results and Conclusions. For most of the analyzed compounds, the highest yields were obtained by ultrasound assisted extraction. The highest temperature during the ultrasonification process (60 °C) increased the efficiency of extraction, without degradation of polyphenols. UAE easily arrives at extraction equilibrium and therefore permits shorter periods of time, reducing the energy input. Furthermore, UAE meets the requirements of 'Green Chemistry'. [ABSTRACT FROM AUTHOR]

Moderate alcohol consumption has been shown in many epidemiological investigations to prolong overall life expectancy by reducing the risk of certain diseases. Those that account most for this reduction are coronary heart disease and ischemic stroke, both of which are caused by atherosclerotic vascular disease. It has been claimed that these effects are beverage-specific, with red wine being the most potent. This review examines the relative contributions of ethanol and the polyphenolic antioxidants of red wine by considering their potential to inhibit atherogenesis and the mechanisms involved. There is good evidence, both in vitro and in vivo, that ethanol increases production and circulating levels of HDL-Cholesterol, and reduces clot formation by blocking thrombin activity as well as by inhibition of fibrinolysis. It also prevents migration of smooth-muscle cells to the intimal layer of arteries and reduces the incidence of Type II Diabetes Mellitus, a major risk factor for atherosclerotic disease. Red wine, in addition to ethanol, contains many polyphenolic antioxidants that are also present in fruit and vegetables (such as catechin and quercetin), as well as resveratrol that is almost restricted to grapes and red wine. These polyphenols, especially the last-named, have been shown by in vitro experiments to exhibit many potent proper - ties conducive to preventing atherosclerosis. In addition to lowering clot formation, they diminish inflammatory reactions by down-regulating production of eicosanoids and cytokines, they prevent oxidation of LDL, reduce expression of celladhesion molecules, and increase NO production. However, investigations in whole animals and human subjects have yielded conflicting results. The above paradox can be explained by studies demonstrating that these polyphenols, when taken orally, are rapidly conjugated with glucuronide and sulfate by the small-intestinal mucosa prior to absorption, following which the deactivated water-soluble conjugates are quickly excreted by the kidney. The free biologically-active parent compounds appear in the circulation in very low concentrations and with a very rapid halflife. Uptake by relevant tissues could not be demon strated. In line with this evidence, red and white wines have comparable effects when administered to humans that are essentially attributable to their alcohol content alone. These findings suggest that dietary antioxidants may be less effective than previously thought. .

Introduction The quality of herbs is directly related to the presence of polyphenolic antioxidants. This is the first report on the quantification of individual polyphenolic constituents of Erigeron acris L. Objective To develop a new method using ultra-high performance liquid chromatography with photodiode array and chemiluminescence (UHPLC-PDA-CL) detection for the separation and determination of polyphenols in Erigeron acris extracts. Methodology The methanolic extracts from leaves and inflorescences of Erigeron acris were prepared by ultrasound assisted extraction. The chromatographic separation was performed on C18 column packed with 1.7-μm particles. The post-column CL detection was based on the enhancing effect of polyphenols on the CL generated in manganese(IV)-hexametaphosphate-formaldehyde system. Results The UHPLC method allowed to separate polyphenols in a short running time (13 min), which was three times shorter compared with traditional HPLC. The CL detection was characterised by 6-48 times higher sensitivity and up to three times lower detection limits compared to PDA detection. Qualitative and quantitative differences were observed in polyphenolic composition of Erigeron acris extracts. The main components of leaves were scutellarin and chlorogenic acid, whereas in inflorescences quercetin 3- O-glucoside was predominant. Conclusion Coupling of UHPLC with CL detection has been developed for the first time. This advanced chromatographic technique coupled with sensitive CL detection is a powerful approach for the investigation of polyphenolic profiles in natural products. The shorter analysis time and diminished waste generation makes the UHPLC method more environmentally friendly and more cost-effective in comparison with conventional HPLC. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An automatic flow procedure based on a multicommuted flow analysis (MCFA) for the determination of the total polyphenolic content in food samples employing chemiluminescence (CL) as a detection technique is described. The concept of applying three-way solenoid valves in flow injection analysis was chosen in order to develop an environmentally friendly system which enables minimal consumption of reagents and waste generation. The method was based on the enhancing effect of polyphenolic antioxidants on CL of Mn(IV)-formaldehyde-hexametaphosphate system. The calibration graph obtained for standard solutions of gallic acid was linear in the range 5-150 μg L with a detection limit of 1.5 μg L. The relative standard deviation for 20 measurements was between 1.1 and 2.4 %. The sampling rate was 60 determinations per hour. The proposed method was found to be selective to polyphenol detection and was successfully applied to the determination of the total polyphenol index in 27 diverse plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices and extracts of olive oil). A significant correlation between the total phenolic contentment determined by the MCFA-CL method and the total reducing capacity determined by Folin-Ciocalteu method and total antioxidant activity estimated by the DPPH method was observed. [ABSTRACT FROM AUTHOR]

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL −1 . The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL −1 ), high precision (RSD = 3.3%) and high sample throughput (144 samples h −1 ) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices). [ABSTRACT FROM AUTHOR]

Contents of polyphenolic antioxidants as total polyphenols (TP), free trans-resveratrol (R) and their antiradical activity (ARA) in grape skins and seeds of grape varieties and TP in grape musts originating from 5 wine-growing Czech areas from the harvest 2003 were determined. TP content was determined spectrophotometrically with phenol Folin-Ciocalteau's reagent, R content by HPLC method, and ARA employing the 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH.). Obtained results were evaluated statistically by Statistica programme. TP did not show any statistically significant differences between the analysed varieties (p < 0.05) in grape seeds and skins, but regarding wine-growing regions a significant difference in TP (p < 0.10) in grape skins was found. ARA (p < 0.05) was not significant either for grape seeds or for grape skins in relation to wine-growing regions and varieties. The highest TP contents were found in grape seeds (536.6 mg/g DM), whereas R contents were higher in the skins (av. 1.67 μg/kg DM). Blue grape varieties showed a higher TP content in grape skins and also in must as compared with white grape varieties. The assessment of ARA of extracts of model constituents of grapes tannin (T) and gallic acid (GA) revealed their higher antiradical activity in comparison with ascorbic acid (AA).

Contents of polyphenolic antioxidants as total polyphenols and trans-resveratrol in grape musts, grape skins and seeds of twelve vine varieties from the harvests 2001 and 2002 were determined. Polyphenolic antioxidants of grapes are very effective in preventing cancer and cardiovascular diseases. Total polyphenolic content was determined spectrophotometrically with phenol Folin-Ciocalteau's reagent and trans-resveratrol content by the HPLC method. The average annual total polyphenol contents in the years 2001 and 2002 were 171 mg/land 324 mg/lin the must, 7,470 mg/l and 15,600 mg/kg DM in grape skins and 91,450 and 107,440 mg/kg DM in the seeds. The average annual trans-resveratrol values in the years 2001 and 2002 reached 0.817.10-2 mg/kg DM and 4.97.10-2 mg/kg DM in grape skins and 52.7.10-2 mg/kg DM and 4.63.10-2 mg/kg DM in the seeds and there was hardly any trans-resveratrol presence in the must. The results were evaluated statistically by Statgraphic and Anova programmes. Statistically significant differences in total polyphenols were found between analysed vintages, varieties and contents in seeds and grape skins. Regarding the trans-resveratrol content, statistically significant differences between vintages were found.

A microfluidic system of capillary electrophoresis with electrochemical detection is developed. The process of manufacturing a chip based on polydimethylsiloxane and glass for the determination of electroactive compounds is described. We studied the possibilities of the treatment of the chip channel surface in a gas discharge with sodium dodecyl sulfate, sodium deoxycholate, and an ionic liquid of 1-dodecyl-3-trimethylimidazolium chloride, used as additives to the background electrolyte. It was found that the developed microfluidic system can be used for the determination of polyphenolic antioxidants in green tea and red wine. [ABSTRACT FROM AUTHOR]

Different chemiluminescence systems based on luminol, permanganate, manganese(IV) and cerium(IV) reagents were compared regarding their sensitivity and selectivity to determine plant polyphenols. Among the seventeen systems tested, Mn(IV)-formaldehyde-hexametaphosphate was considered to be the most suitable for polyphenols detection. The developed flow injection method (FI-CL) based on enhancing effect of polyphenols on Mn(IV) chemiluminescence is characterised by low detection limit of gallic acid (0.02 μg L −1 ) and high precision (RSD = 1.7%). The calibration graph was linear from 0.1 to 100 μg L −1 . The selectivity studies revealed that the FI-CL method ensures accurate determination of the total polyphenols content in food samples. The method was successfully applied to analysis of a variety of plant-derived foods (wine, tea, cereal coffee, fruit and vegetable juices, herbs and spices). The proposed method is superior to conventional spectrophotometric assays due to its higher sample throughput (195 samples h −1 ), simplicity, sensitivity and, above all, higher selectivity. [ABSTRACT FROM AUTHOR]

Curcumin, a polyphenolic antioxidant derived from the turmeric root has undergone extensive preclinical development, showing remarkable efficacy in wound repair, cancer and inflammatory disorders. This review addresses the rationale for its use in neurodegenerative disease, particularly Alzheimer's disease. Curcumin is a pleiotropic molecule, which not only directly binds to and limits aggregation of the β-sheet conformations of amyloid characteristic of many neurodegenerative diseases but also restores homeostasis of the inflammatory system, boosts the heat shock system to enhance clearance of toxic aggregates, scavenges free radicals, chelates iron and induces anti-oxidant response elements. Although curcumin corrects dysregulation of multiple pathways, it may exert many effects via a few molecular targets. Pharmaceutical development of natural compounds like curcumin and synthetic derivatives have strong scientific rationale, but will require overcoming various hurdles including; high cost of trials, concern about profitability and misconceptions about drug specificity, stability, and bioavailability. [ABSTRACT FROM AUTHOR]

With the increasing interest in functional products, liqueurs have become an interesting area of research, trying to confirm the correlation between their chemical composition and beneficial health effects. Chocolate, as a good source of polyphenols, and ethanol, an effective solvent for their extraction, is a good starting point for production of chocolate liqueurs as potentially functional products. The aim of this research was to determine changes in the content of polyphenols and antioxidant capacity of chocolate liqueurs produced from chocolates with cocoa solids content of 30% and 72% in combination with two concentrations of ethanol (20% and 30%) during 3 months of storage. Contents of total phenols, flavonoids, flavan-3-ols and proanthocyanidins were determined spectrophotometrically as well as the antioxidant capacity, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Initially determined values of the above mentioned parameters were the highest in chocolate liqueur made from chocolate containing 72% of cocoa solids combined with 30% ethanol. Storage did not have marked impact on total phenol content of evaluated liqueurs, although the individual phenolic subgroups exhibited notable changes, both decrease (flavonoids and flavan-3-ols) and increase (proanthocyanidins) in their respective contents. [ABSTRACT FROM AUTHOR]

Electrogenerated hexacyanoferrate(III) ions have been used as coulometric titrant for the determination of total free polyphenols in beverages. Stoichiometric coefficients of natural flavonoids (rutin, quercetin, and taxifolin) in their reaction with [Fe(CN)] ions were established. The number of electrons involved in the oxidation corresponds to number of phenolic OH groups in the molecule of polyphenols. Proteins (casein and bovine serum albumin) bind polyphenols in the complexes that leads to significant decrease of free polyphenols portion (in the range of 5-76%). Ferric reducing power (FRP) of eight tea and 17 coffee samples was determined. The absolute FRP values ranged from 224 to 405 and from 241 to 488 C cup for tea and coffee, respectively. Effect of milk proteins on total free polyphenols of tea and coffee and appropriate alteration of beverages FRP were evaluated. Milk addition decreases FRP of drinks in the range of 10-70% reflecting high content of inactive polyphenols. [ABSTRACT FROM AUTHOR]

The present study explored the use of chitosan films functionalized with antioxidants extracted from Larix decidua Mill. bark for active packaging. The pristine chitosan and extract-incorporated chitosan films were evaluated for their structural, physico-mechanical, thermal, viscoelastic and antioxidant properties using advanced characterization techniques. The infrared spectroscopy revealed hydrogen bonding between the extract polyphenolic antioxidants and chitosan, whereas the surface microscopy studies indicated good compatibility between them. The addition of bark extract caused a significant increase in color parameters and solubility with reduction in swelling and elongation at break of the films. The thermal analysis indicated a drop in thermal stability of chitosan films modified with the extract. The dynamic mechanical analysis confirmed the extract-polymer interactions and the viscoelastic nature of the films. The incorporation of bark extract caused remarkable enhancement in the antioxidant activity of chitosan films. Overall, larch bark extract-functionalized chitosan films demonstrated promising potential for food packaging. • Active packaging films developed with larch bark extractives and chitosan • Extract altered the physico-mechanical properties and microstructure of the films. • Non-covalent interactions observed between bark extractives and chitosan • Huge increase in antioxidant activity of extract-functionalized chitosan films • Good compatibility found between bark extract and chitosan matrix [ABSTRACT FROM AUTHOR]

Abstract: A gas chromatographic–mass spectrometric (GC–MS) method is proposed for the detection and quantification of lathosterol in rabbit brain. This compound is one of the most important precursors of the cholesterol synthesis. The interest in brain cholesterol metabolism is growing nowadays since it was described to play an important role in some neurodegerative disorders such as Alzheimer''s disease and Multiple Sclerosis. The analytical methodology proposed involves a liquid–liquid extraction procedure (LLE) followed by a silylation step previous to the GC–MS analysis. The chromatographic separation was performed by using a low bleed HP5-MS fused silica capillary column. A clean up is not necessary when using single-ion monitoring (SIM) mode. The molecular ion appears at 458 m/z; being as well the base peak. α-Naphtol was used as an internal standard. The detection limit obtained was 0.09μgmL−1. The method was applied to the determination of brain lathosterol levels in rabbits fed with different types of diets (control and atherogenic, supplemented or not with natural polyphenolic antioxidants). The quantification of the compound in samples showed a reduction, after 1 month, of this precursor of cholesterol synthesis in groups fed with antioxidant supplemented diets. [Copyright &y& Elsevier]

Abstract: Solid-state optical sensor membranes based on immobilised chromogenic radicals for the assessment of antioxidant activity have been studied. Two stable lipophilic chromogenic radicals, DPPHhenyl-1-picrylhydrazyl radical) and galvinoxyl radical, GV-tert-butyl-α-(3,5-di-tert-butyl-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy radical), were immobilised in plasticised PVC films and screened for suitability as indicators of antioxidative activity. The spectrophotometric characterisation of the polymer films containing immobilised free radicals was performed, and the response of the immobilised free radicals toward standard antioxidants was studied. It has been demonstrated that the immobilised radicals retain their reactivity towards antioxidants and the results suggest that the reactivity of immobilised radicals is comparable to standard solution-based DPPH assays. Polymer films containing immobilised DPPHrespond to standard antioxidants in aqueous solutions by changing colour irreversibly from purple (absorption maximum at 520nm) to yellow. The initial slopes of the response curves to the phenolic antioxidant gallic acid, obtained in the 1–50mM concentration range, gave a linear calibration plot in a 1min exposure cuvette test. The polymer films were used to screen antioxidative activity of beverage and food samples known to contain antioxidants, such as black and green tea, coffee, red wine, fruit juice, olive oil and sunflower oil. It has been demonstrated that a rapid and simple qualitative screening test of untreated samples is possible using a test strip based on immobilised DPPH [Copyright &y& Elsevier]

To better understand the biochemical consequences when polymeric polyphenols serve as biological antioxidants, we studied how reaction pH (pH 2.1-7.4) and protein affected the oxidation of pentagalloyl glucose (PGG) by NaIO 4 in aqueous solution. PGG oxidation produced an o -semiquinone radical intermediate, which tended to form polymeric products at pH values below 5, and o -quinones at higher pH. The model protein bovine serum albumin promoted the formation of quinone even at low pH. Two other polyphenols, procyanidin (epicatechin 16 -(4→8)-catechin) and epigallocatechin gallate, had similar pH-dependent oxidation patterns. [ABSTRACT FROM AUTHOR]

• HPLC analysis of litchi leaf revealed the presence of polyphenolic antioxidants. • Litchi leaf markedly reduced the level of several oxidative stress in 2K1C rats. • Litchi leaf improved the level of endogenous antioxidant enzymes in 2K1C rats. • It improved the kidney and heart function reducing uric acid, creatinine and CK-MB. The study aimed to investigate the nephroprotective and cardioprotective effects of ethanol extract of litchi leaf (LI) in two-kidney-one-clip (2K1C) rat model. HPLC analysis revealed the presence of several polyphenolic antioxidants in LI. Correspondingly, LI at 50–200 mg/kg reduced the level of oxidative stress markers (MDA, APOP, NO) and improved level of endogenous antioxidant enzymes (CAT, SOD) in 2K1C rats. Besides, LI caused significant improvements in kidney and heart functions in 2K1C rats by reducing the plasma level of uric acid and creatinine as well as CK-MB. Consistent with the biochemical findings, histopathological data further confirmed that LI is effective in decreasing heart and kidney injuries, oxidative stress and inflammation which ensued in 2K1C rats. Collectively, the outcomes suggest that the LI enriched in polyphenolic antioxidants may provide the protection against excessive oxidative stress, inflammation and tissue injury, thereby improving the kidney and heart function in 2K1C rats. [ABSTRACT FROM AUTHOR]