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The present study evaluated three green extraction methods, accelerated solvent extraction (ASE), ultrasound-assisted extraction (UAE), and laser irradiation extraction (LE), for the polyphenolic compounds and vitamin C extraction of Cornus mas L. and Crataegus monogyna fruit extracts. The polyphenols and vitamin C of extracts were quantified using HPLC-DAD, and the total phenolic content, flavonoid content, antioxidant activity (DPPH and reducing power), and antidiabetic activity were also studied. The antidiabetic activity was examined by the inhibition of alpha-amylase and alpha-glucosidase, and in vitro on a beta TC cell line (beta-TC-6). The results showed significant differentiation in the extraction yield between the methods used, with the ASE and LE presenting the highest values. The C. mas fruit extract obtained by ASE exhibited the best antioxidant activity, reaching an IC50 value of 31.82 +/- 0.10 mu g/mL in the DPPH assay and 33.95 +/- 0.20 mu g/mL in the reducing power assay. The C. mas fruit extracts obtained by ASE and LE also have the highest inhibitory activity on enzymes associated with metabolic disorders: alpha-amylase (IC50 = 0.44 +/- 0.02 mu g/mL for the extract obtained by ASE, and 0.11 +/- 0.01 mu g/mL for the extract obtained by LE at combined wavelengths of 1270 + 1550 nm) and alpha-glucosidase (IC50 of 77.1 +/- 3.1 mu g/mL for the extract obtained by ASE, and 98.2 +/- 4.7 mu g/mL for the extract obtained by LE at combined wavelengths of 1270 + 1550 nm). The evaluation of in vitro antidiabetic activity demonstrated that the treatment with C. mas and C. monogyna fruit extracts obtained using ASE stimulated the insulin secretion of beta-TC-6 cells, both under normal conditions and hyperglycemic conditions, as well. All results suggest that C. mas and C. monogyna fruit extracts are good sources of bioactive molecules with antioxidant and antidiabetic activity.

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In recent years, various studies have been carried out to increase the concentration of antioxidant active principles in red wines as a consequence of the effects of winemaking techniques on the polyphenols content. In this study, in order to obtain the most optimal wine in terms of content and efficiency of antioxidant activity, various winemaking technologies (punching-down and pumping-over maceration) were tried with diverse gradations (Feteasca Neagra and Cabernet Sauvignon wines) and the addition of different concentrations of melatonin in must. Suitable HPLC and spectrophotometric methods were used to follow the evolution of the antioxidant compounds from wines during aging (for 12 months). After comparing the acquired results, an increase was observed in the antioxidant compound concentrations, particularly in resveratrol (85%), peonidin-3-glucoside (100%) or cyanidin-3-glucoside (100%), and antioxidant activity (10-40%). The most enriched wine was obtained in the case of Feteasca Neagra by the addition of 0.5 mg of melatonin per 1 kg of must using the punch-down technology and, in the case of Cabernet Sauvignon, by the addition of 0.05 mg of melatonin per 1 kg of must using the pumping-over technique. This study can provide winemakers with an approach to enhance red wines with antioxidant compounds.

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The present study evaluated the antioxidant and antidiabetic properties of Medicago sativa and Solidago virgaurea extracts enriched in polyphenolic compounds. The extracts were obtained by accelerated solvent extraction (ASE) and laser irradiation. Then, microfiltration was used for purification, followed by nanofiltration used to concentrate the two extracts. The obtained extracts were analyzed to determine their antioxidant activity using DPPH radical scavenging and reducing power methods. The antidiabetic properties have been investigated in vitro on a murine insulinoma cell line (beta-TC-6) by the inhibition of alpha-amylase and alpha-glucosidase. M. sativa obtained by laser irradiation and concentrated by nanofiltration showed the highest DPPH center dot scavenging (EC50 = 105.2 +/- 1.1 mu g/mL) and reducing power activities (EC50 = 40.98 +/- 0.2 mu g/mL). M. sativa extracts had higher inhibition on alpha-amylase (IC50 = 23.9 +/- 1.2 mu g/mL for concentrated extract obtained after ASE, and 26.8 +/- 1.1), while S. virgaurea had the highest alpha-glucosidase inhibition (9.3 +/- 0.9 mu g/mL for concentrated extract obtained after ASE, and 8.6 +/- 0.7 mu g/mL for concentrated extract obtained after laser extraction). The obtained results after evaluating in vitro the antidiabetic activity showed that the treatment with M. sativa and S. virgaurea polyphenolic-rich extracts stimulated the insulin secretion of beta-TC-6 cells, both under normal conditions and under hyperglycemic conditions as well. This paper argues that M. sativa and S. virgaurea polyphenolic-rich extracts could be excellent natural sources with promising antidiabetic potential.

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Until recently, the main antioxidant role among wine constituents was attributed to polyphenolic compounds, but once the presence of melatonin in wines was confirmed, an interesting new field of research opened up due to its possible synergistic effects with other antioxidants in the winemaking process, which may lead to a change in the profile of polyphenolic compounds and antioxidant activity. In order to investigate the evolution of active principles from the phenylpropanoid metabolism associated with the synergistic effects of melatonin, for the first time, a melatonin treatment was performed in the pre-stage of the different winemaking processes of Feteasca Neagra and Cabernet Sauvignon wines with different melatonin concentrations. After comparing the acquired results for the evolution of the polyphenolic compound profile and antioxidant activity of treated wines, we ascertained an increase in the antioxidant compound concentrations, especially in resveratrol, quercetin, and cyanidin-3-glucoside, directly proportional to the used melatonin concentration; an intensification in activity of PAL and C4H enzymes; and the modification in the expression of specific anthocyanin biosynthesis genes, especially UDP-D-glucose-flavonoid-3-O-glycosyltransferase. It was also shown that the application of melatonin in the pre-stage of the winemaking process can be successfully used to obtain red wines with increased antioxidant activity (almost 14%).

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The electrochemical behaviour of the flavonoid naringenin (NGN) was investigated for the first time by cyclic voltammetry (CV), using a disposable electroactivated pencil graphite electrode (PGE*). In this electrochemical sensor, NGN is irreversibly oxidized, giving rise to two pH-dependent peaks due to mixed (diffusion- and adsorption-controlled) electrode processes involving the same number of electrons and protons, namely two and one, respectively. Exploiting these peaks, differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at PGE* in 0.05 mol L-1 potassium hydrogen phthalate were applied for quantitative determination of NGN. The new proposed methods presented linear ranges covering more than three orders of magnitude (7.86 x 10(-8) to 1.82 x 10(-4) mol L-1 NGN for DPV and 7.50 x 10(-8) to 1.00 x 10(-4) mol L-1 NGN for SWV) and low limits of detection (LoD) and quantification (LoQ) (LoD = 3.06 x 10(-8) mol L-1, LoQ = 1.02 x 10(-7) mol L-1 NGN for DPV and LoD = 4.40 x 10(-8) mol L-1, LoQ = 1.11 x 10(-7) mol L-1 NGN for SWV), similar to or better than those reported in the literature. The developed voltammetric methods were applied with good results to determine the intermediate antioxidant power polyphenolics content expressed as mg naringenin equivalent per L grapefruit juice.

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The electrochemical behaviour of the flavonoid naringenin (NGN) was investigated for the first time by cyclic voltammetry (CV), using a disposable electroactivated pencil graphite electrode (PGE∗). In this electrochemical sensor, NGN is irreversibly oxidized, giving rise to two pH-dependent peaks due to mixed (diffusion- and adsorption-controlled) electrode processes involving the same number of electrons and protons, namely two and one, respectively. Exploiting these peaks, differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at PGE∗ in 0.05 mol L -1 potassium hydrogen phthalate were applied for quantitative determination of NGN. The new proposed methods presented linear ranges covering more than three orders of magnitude (7.86 × 10 -8 to 1.82 × 10 -4 mol L -1 NGN for DPV and 7.50 × 10 -8 to 1.00 × 10 -4 mol L -1 NGN for SWV) and low limits of detection (LoD) and quantification (LoQ) (LoD = 3.06 × 10 -8 mol L -1 , LoQ = 1.02 × 10 -7 mol L -1 NGN for DPV and LoD = 4.40 × 10 -8 mol L -1 , LoQ = 1.11 × 10 -7 mol L -1 NGN for SWV), similar to or better than those reported in the literature. The developed voltammetric methods were applied with good results to determine the intermediate antioxidant power polyphenolics content expressed as mg naringenin equivalent per L grapefruit juice. © 2018 The Royal Society of Chemistry.

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Prussian blue modified with copper was electrodeposited on a platinum microelectrode for the amperometric determination of hydrogen peroxide at -50 mV. The Prussian blue-copper layer was stable for 2 h at pH 7.4 and a storage period of 2 months. The Prussian blue-copper modified microelectrodes were used to develop oxidase based microbiosensors for ethanol and lactate. Lactate and alcohol oxidases were immobilized by cross-linking with glutaraldehyde. No interferences were observed from possible interfering compounds up to a concentration of 0.5 mM. The calibration plot of the lactate microbiosensor was linear between 0.005 and 0.2 mM with a limit of detection of 0.0035 mM lactate. The linear dynamic range of the alcohol microbiosensor was between 0.05 and 2 mM and the limit of detection was 0.02 mM ethanol. The developed microbiosensors were used for the analysis of pickled cucumber juice, yogurt, and wine.

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The quality of red wines is given by phenolic compounds and anthocyanins and is associated with colour, taste and therapeutic effects on human health. This work aims to provide a detailed profile of phenolic compounds and anthocyanins that are found in five red wine samples from Dealu Mare-Valea Calugareasca region. The phenolic and anthocyanin profiles of the red wine samples were determined by high-performance liquid chromatography-photodiode array-mass spectrometry and matrix-assisted laser desorption/ionisation-time of flight, respectively. The results obtained showed that Feteasca Neagra had the highest content of phenolic compounds followed by Pinot Noir while the preponderant compound was gallic acid. Amongst anthocyanins, malvidin was found to be the major compound and the highest anthocyanin content was found also for Feteasca Neagra wine. A simple high-performance liquid chromatography-photodiode array-mass spectrometry method was developed, optimised and applied for the quantification of phenolic compounds in red wine samples from Dealu Mare-Valea Calugareasca region. In the same time, a rapid matrix-assisted laser desorption/ionisation-time of flight method that does not need sample preparation was applied for the identification of anthocyanins. Moreover, the phenolic and anthocyanin composition of red wines from Dealu Mare-Valea Calugareasca region is reported for the first time. The phenolic and anthocyanin profile determination will be beneficial for the Romanian winemakers to produce high-quality red wines.

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Experimentally developed ceramic pots, with two different sizes of grain, were half-filled with wine and subjected to thermal alteration at constant elevated temperature ((60 +/- 2)A degrees C) in darkness for 12 weeks. This work sought to characterise the samples thereby obtained from chemical and mineralogical perspectives using scanning electron microscopy and an energy-dispersive X-ray microanalysis system (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and capillary electrophoresis (CE) with UV detection as an alternative to chromatographic methods, due to its good resolution, automation, simplicity, high speed, low consumption of chemicals and short time required for sample preparation. The capillary electrophoresis method was used for the detection of five wine biomarkers: succinic acid, malic acid, tartaric acid, citric acid and lactic acid. In general, it was noted that the fine-grained ceramic assortment retained the organic material better than the coarser-grained ceramics. An interesting observation derived from this study was that not only could tartaric acid be considered as a biomarker for wine residues in archaeological pottery, but malic acid could also act similarly for white wine and lactic acid for red wine.

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They were characterized by Fourier transform infrared spectroscopy (FTIR). The efficiency of EA entrapment revealed values >= 50%. The released ellagic acid quantities were spectrophotometrically determined at various time intervals: 1, 2, 3, 7 days, and various pH: 3.0, 7.5, 8.0, 9.0. The best cumulative release of ellagic acid from membranes was obtained at lowest pH, pH=3. The antioxidant capacity of EA released from membranes was evaluated by inhibition percent of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The best result was found also at pH=3.0, 20% DPPH inhibition (at 48h). The properties of such membranes recommend them as biomaterial with controlled antioxidant biological activity.

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They were characterized by Fourier transform infrared spectroscopy (FTIR). The efficiency of EA entrapment revealed values ≥ 50%. The released ellagic acid quantities were spectrophotometrically determined at various time intervals: 1, 2, 3, 7 days, and various pH: 3.0, 7.5, 8.0, 9.0. The best cumulative release of ellagic acid from membranes was obtained at lowest pH, pH=3. The antioxidant capacity of EA released from membranes was evaluated by inhibition percent of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The best result was found also at pH=3.0, 20% DPPH inhibition (at 48h). The properties of such membranes recommend them as biomaterial with controlled antioxidant biological activity.