Metabolomics analysis based on UHPLC-QqQ-MS/MS to discriminate grapes and wines from different geographical origins and climatological characteristics

With the proliferation of the consumer's awareness of wine provenance, wines with unique origin characteristics are increasingly in demand. This study aimed to investigate the influence of geographical origins and climatological characteristics on grapes and wines. A total of 94 anthocyanins and 78 non-anthocyanin phenolic compounds in grapes and wines from five Chinese viticultural vineyards (CJ, WH, QTX, WW, and XY) were identified by UHPLC-QqQ-MS/MS. Chemometric methods PCA and OPLS-DA were established to select candidate differential metabolites, including flavonols, stilbenes, hydroxycinnamic acids, peonidin derivatives, and malvidin derivatives. CCA showed that malvidin-3-O-glucoside had a positive correlation with mean temperature, and quercetin-3-O-glucoside had a negative correlation with precipitation. In addition, enrichment analysis elucidated that the metabolic diversity in different origins mainly occurred in flavonoid biosynthesis. This study would provide some new insights to understand the effect of geographical origins and climatological characteristics on phenolic compounds in grapes and wines.

The profiles of free, esterified and insoluble-bound phenolics in peach juice after high pressure homogenization and evaluation of their antioxidant capacities, cytoprotective effect, and inhibitory effects on α-glucosidase and dipeptidyl peptidase-Ⅳ

The phenolic profiles, antioxidant capacities, cytoprotective effect, and α-glucosidase and DPP-IV inhibitory capacity of free (FP), esterified (EP) and insoluble-bound (IBP) phenolic fractions in 'Lijiang snow' peach juice after high pressure homogenization (HPH) were investigated, and the molecular docking was used to explore the enzyme inhibition mechanism. HPH increased total phenolic and total flavonoid contents in three fractions without changing compositions. The IC50 of radicals scavenged by three fractions were all reduced by HPH. The best inhibition on intracellular ROS production were found for phenolic fractions after HPH at 300 MPa, with ROS levels ranged within 95.26-119.16 %. HPH at 300 MPa reduced the apoptosis rates of FP and EP by 16.52 % and 9.33 %, respectively. All phenolic fractions showed effective inhibition on α-glucosidase and DPP-IV by formation of hydrogen bonding and van der Waals forces. This study explored the feasibility of HPH to enhance the phenolics and bioactivity of peach juice.

The effect of in vitro digestion, food matrix, and hydrothermal treatment on the potential bioaccessibility of selected phenolic compounds

The effects of in vitro digestion, hydrothermal treatment, and food matrices (wheat flour, durum wheat flour, wholemeal wheat flour, corn flour, rice flour) on the bioaccessibility of phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, chlorogenic acid, catechin) were investigated. The influence of experimental factors and their combinations was estimated based on the "Dose Correction Index" (DCI) concept. Generally, the applied conditions had a negative effect on the bioaccessibility of polyphenols; however, the effect depended on the type of compound and food matrix, which was reflected in different DCI values. A less unfavorable effect on the bioaccessibility was exerted by the rice flour (the lowest DCI values), but the most negative impact was found in the case of the wholemeal wheat flour. The DCI concept provides basic knowledge of the magnitude of factors affecting the bioaccessibility of polyphenols, which can be useful for designing fortified products with desirable bioactivity.

Foliar-sprayed manganese sulfate improves flavonoid content in grape berry skin of Cabernet Sauvignon (Vitis vinifera L.) growing on alkaline soil and wine chromatic characteristics

Flavonoids are key determinants of grape quality and wine color. Grapevines growing in alkaline soil are prone to manganese deficiency, which can decrease the contents of secondary metabolites, including flavonoids. We determined the effects of a foliar Mn treatment (MnSO₄·H₂O) of Cabernet Sauvignon grapevines (V. vinifera L.) growing in alkaline soil on the flavonoid contents in grape skin, and the quality of wine. The Mn treatments were applied in 2017 and 2018, and tended to increase the grape sugars, berry weight, and the contents of phenolic compounds from veraison until harvest. The Mn treatments increased the amounts of acetylated, methylated, and total anthocyanins, as well as the total flavonol contents in grape berry skin at harvest. The wines prepared from these grapes had a higher color intensity than those prepared from grapes from control vines. Foliar-applied MnSO₄·H₂O can promote flavonoid biosynthesis in grape berries, and improve the color of wine.

Effects of UV-C treatment and ultrafine-grinding on the biotransformation of ergosterol to vitamin D2, physiochemical properties, and antioxidant properties of shiitake and Jew's ear

In the present study, the impact of ultraviolet (UV)-C treatment and ultrafine grinding on the conversion of ergosterol to vitamin D₂, physiochemical properties, and antioxidant properties of shiitake and Jew's ear was assessed. After exposure to UV-C, vitamin D₂ contents of both the mushroom samples has increased significantly (p < 0.05). Whereas, ultrafine grinding along with UV-C treatment has a synergistic effect on bioconversion of ergosterol to vitamin D₂ and this effect is more prominent in low dose UV-C irradiation groups (2 kJ/m²). Ultrafine grinding significantly (p < 0.05) improved the water holding capacity (WHC), water solubility index (WSI) and polysaccharide dissolution rate (PDR). However, UV-C treatment led to insignificant changes in the physiochemical properties of mushroom samples. A significant improvement was also observed in the antioxidant profiles especially tannin contents of mushrooms followed by the ultrafine grinding and UV-C treatment.

Recovery of phenolic antioxidants from Syrah grape pomace through the optimization of an enzymatic extraction process

Phenolic compounds are highly valuable products that remain trapped in grape pomace, an abundant winery by-product. Therefore, efficient extraction procedures of these compounds represent a route for grape pomace valorisation. Here we performed a screening of the factors affecting the aqueous enzymatic extraction of phenolic compounds from Syrah grape pomace, including the following independent variables: temperature, pH, pectinase, cellulase and tannase; and a subsequent optimization through response surface methodology. At the optimal region, the enzymatic treatment enhanced the extraction yield of phenolics by up to 66% and its antioxidant capacity by up to 80%, reducing the incubation time and enzyme doses in respect to previous studies. We found that tannase raises the antioxidant capacity of the extract by the liberation of gallic acid, while cellulose favours the liberation of p-coumaric acid and malvidin-3-O-glucoside. We also tested the procedure in different grape pomace varieties, verifying its wide applicability.

Flavanol plasma bioavailability is affected by metabolic syndrome in rats

Flavanols, which exert several health benefits, are metabolized after ingestion. Factors such as the host physiological condition could affect the metabolism and bioavailability of flavanols, influencing their bioactivities. This study aimed to qualitatively evaluate whether a pathological state influenced flavanol plasma bioavailability. Standard and cafeteria (CAF) diet fed rats, a robust model of metabolic syndrome (MeS), were administered 1000mg/kg of flavanol enriched grape seed polyphenol extract (GSPE). Flavanols and their metabolites were quantified by HPLC-MS/MS in plasma before and at 2, 4, 7, 24, and 48h after GSPE ingestion. Results showed that in CAF administered rats the maximum time of plasma flavanol concentration was delayed and these animals presented higher levels of plasma phase-II metabolites as well as altered microbial metabolites. In conclusion, this study demonstrated that MeS pathological state modified flavanol bioavailability, supporting the hypothesis that flavanol metabolism, and therefore flavanol functionality, depend on the organism's state of health.

Phenolics, antioxidant capacity and bioaccessibility of chicory varieties (Cichorium spp.) grown in Turkey

In this study, the changes in phenolics, anthocyanin, antioxidant capacity, and bioaccessibility of chicory varieties (Cichorium spp.) in Turkey were investigated. A total of 19 phenolic standards were screened in the chicory varieties studied and the most abundant compounds in the samples, extracted with methanol, were phenolic acids, syringic (2.54mg/kg) and trans-ferulic acid (1.85mg/kg), whilst (+)-catechin was the major flavanol. The highest flavanol content using either methanol or ethanol was determined in the green chicory samples (0.62mg/kg). The red chicory variety had higher anthocyanin (12.80mg/kg), and contained more phenolics, extractable (8855.50mg GAE/100g) and hydrolysable (7005.51mg GAE/100g), than the other varieties. Also, the antioxidant capacities in this variety, as measured using the CUPRAC assay (570.54 and 425.14μmol Trolox/g dw, respectively), had a wider range of difference than was found in the other assays used. Total phenolics were more bioaccessible from the white chicory variety (61.48%). However, the bioaccessibility of antioxidants was higher in the green chicory variety.

Quinones as Strecker degradation reagents in wine oxidation processes

The Strecker aldehydes formed during the reaction between α-amino acids (phenylalanine or methionine) and either gallic acid, caffeic acid or (+)-catechin ortho-quinones were evaluated in wine-model systems. It was demonstrated that phenylacetaldehyde was formed by quinone intermediates at wine pH. The highest amounts of phenylacetaldehyde during the 10days of experiment (69±5µg/L/day; 7x>Control) were obtained from (+) catechin, followed by gallic acid (61±4µg/L/day; 6x>Control) and caffeic acid (41±4µg/L/day; 4x>Control). The intermediate structures delivered from the reaction of ortho-quinones with α-amino acids were demonstrated by MSⁿ.

Effect of harvest time on some in vitro functional properties of hop polyphenols

Health benefits of hop polyphenols are well studied. In the present investigation, we examined the antioxidant activity, anti-nitric oxide (NO) production, and anti-adipocyte differentiation of polyphenols extracted from hops (HPP), harvested at different times for over 4years. Saaz hop variety from the Czech Republic was used in the in vitro assays. Twenty-three polyphenols were quantitatively analyzed using Orbitrap liquid chromatography-mass spectrometry (LC-MS), and their health promoting effects were assayed individually. Strong effects of low concentrations of HPP were observed in the above three assays. A significant increase in anti-adipocyte differentiation activity per unit weight of HPP was obtained in the early harvested samples. A significant difference in anti-NO production activity per unit weight of HPP was observed among the different harvest years. HPP significantly increased in early harvested samples. Our results suggest that some in vitro functional properties of hops vary with harvest time and year and are dependent on different polyphenols.

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.

Anti-inflammatory and antinociceptive activities of Croton urucurana Baillon bark

ETHNOPHARMACOLOGICAL RELEVANCE

Croton urucurana (Euphorbiaceae) is popularly used in Brazil to treat inflammatory processes, pain, and gastric ulcers.

AIM OF STUDY

To evaluate the anti-inflammatory and antinociceptive properties of the methanol extract from the bark of C. urucurana (MECu) in mice and identify its chemical constituents.

MATERIALS AND METHODS

The extract was characterized by UHPLC-DAD-ESI-Q-TOF-MS/MS. Extract doses of 25, 100, and 400mg/kg were employed in the biological assays. Evaluation of anti-inflammatory activity was based on paw edema and leukocyte recruitment into the peritoneal cavity of mice, both induced by carrageenan. Abdominal writhing caused by acetic acid and duration of formalin-induced paw-licking were the models employed to evaluate antinociceptive activity.

RESULTS

Ten compounds were identified in the extract: (+)-gallocatechin (1), procyanidin B3 (2), (+)-catechin (3), (-)-epicatechin (4), tembetarine (5), magnoflorine (6), taspine (7), methyl-3-oxo-12-epi-barbascoate (8), methyl-12-epi-barbascoate (9), and hardwickiic acid (10). This is the first report of compounds 2, 4, 6, 7, and 10 in C. urucurana and compound 5 in the genus Croton. In addition to inhibiting paw edema and leukocyte recruitment (particularly of polymorphonuclear cells) into the peritoneal cavity of mice, MECu reduced the number of abdominal writhings induced by acetic acid and the duration of formalin-induced paw licking.

CONCLUSIONS

The methanol extract of C. urucurana bark exhibited anti-inflammatory and antinociceptive properties, corroborating its use in folk medicine. These effects may be related to the presence of diterpenes, alkaloids, and flavonoids.

Phytochemical distribution in hull and cotyledon of adzuki bean (Vigna angularis L.) and mung bean (Vigna radiate L.), and their contribution to antioxidant, anti-inflammatory and anti-diabetic activities

Total saponin content, total phenolics content, total flavonoids content, condensed tannin content in hull, cotyledon and whole grain of both adzuki bean and mung bean were determined by colorimetric methods. Vitexin and isovitexin contents in mung bean were determined by HPLC. Antioxidant effects were evaluated with DPPH scavenging activity and ferric reducing antioxidant power assay. In vitro anti-inflammatory and anti-diabetic effects of beans were evaluated by protease and aldose reductase inhibitory assays, respectively. The results indicated that the bean hulls were the most abundant in phytochemicals and largely contributed antioxidant activities, anti-inflammatory effects and anti-diabetic effects of whole grains. The result showed that mung bean hull was the most abundant with vitexin at 37.43 mg/g and isovitexin at 47.18 mg/g, respectively. Most of the phytochemicals and bioactivities were most predominantly contributed by the bean hulls with exception for condensed tannin of mung bean; which was more abundant in the cotyledon than its hull.

Bioassay-guided isolation of proanthocyanidins with antioxidant activity from peanut (Arachis hypogaea) skin by combination of chromatography techniques

Purification and bioassay-guided fractionation were employed to isolate proanthocyanidins with antioxidant activity from peanut skin (Arachis hypogaea Runner 886). The crude extract was prepared with acetone (60% v/v) and purified using chromatographic methods, including a semipreparative HPLC technique. As a result, two proanthocyanidins were isolated and identified using NMR, epicatechin-(2 β → O → 7, 4 β → 8)-catechin (proanthocyanidin A1) and epicatechin-(β → 2 O → 7, 4 β → 8)-epicatechin (proanthocyanidin A2). Despite the structural similarity, differences were observed in their antioxidant activity. Proanthocyanidin A1 proved to be more active, with EC50 value for DPPH radical scavenging of 18.25 μg/mL and reduction of Fe(3+)-TPTZ complex of 7.59 mmol/g, higher than that of synthetic antioxidant BHT. This compound evaluated by ABTS(+) was similar to that of natural quercetin. Therefore, peanut skin is an important source of bioactive compounds that may be used as a mild antioxidant for food preservation.

Influence of the temperature and oxygen exposure in red Port wine: A kinetic approach

Although phenolics are recognized to be related with health benefits by limiting lipid oxidation, in wine, they are the primary substrates for oxidation resulting in the quinone by-products with the participation of transition metal ions. Nevertheless, high quality Port wines require a period of aging in either bottle or barrels. During this time, a modification of sensory properties of wines such as the decrease of astringency or the stabilization of color is recognized to phenolic compounds, mainly attributed to anthocyanins and derived pigments. The present work aims to illustrate the oxidation of red Port wine based on its phenolic composition by the effect of both thermal and oxygen exposures. A kinetic approach toanthocyanins degradation was also achieved. For this purpose a forced red Port wine aging protocol was performed at four different storage temperatures, respectively, 20, 30, 35 and 40°C, and two adjusted oxygen saturation levels, no oxygen addition (treatment I), and oxygen addition (treatment II). Three hydroxycinnamic esters, three hydroxycinnamic acids, three hydroxybenzoic acids, two flavan-3-ols, and six anthocyanins were quantitated weekly during 63days, along with oxygen consumption. The most relevant phenolic oxidation markers were anthocyanins and catechin-type flavonoids, which had the highest decreases during the thermal and oxidative red Port wine process. Both temperature and oxygen treatments affected the rate of phenolic degradation. In addition, temperature seems to influence mostly the phenolics kinetic degradation.

Effects of defoliation on quality attributes of Nero di Troia (Vitis vinifera L.) grape and wine

Field studies were conducted in Puglia (Italy) to evaluate the influence of defoliation around cluster zones on grape and wine quality. Nero di Troia grapes were subjected to four different treatments: N: no leaf removal; E: leaf removal in the area of the clusters along the east side (at complete veraison); E/W: leaf removal in the area of the clusters along the east and west side (at complete veraison); and F: almost complete leaf removal along the west side (at complete veraison) and at pre-harvest also along the east side. Grapes of defoliated vines generally showed higher sugar content, lower titratable acidity, total flavonoids, flavonoids different from anthocyanins, and total phenolic content than grapes from non-defoliated vines while their total anthocyanin concentration was not affected by defoliation at a significant level. Concerning wines, alcohol content, residual soluble solids, different forms of anthocyanins but also volatile acidity were generally higher in samples from defoliated vines. Differences were also highlighted among the defoliation treatments: the best results in terms of dry matter, sugar and alcohol content were observed in the samples submitted to the more severe defoliation as a consequence of the higher light availability and berry temperature. Concerning the concentration of the individual phenolics, significant differences were highlighted for: caffeic and caftaric acids, peonidin- and malvidin-3-p-coumaroylglucoside, which were higher in the E wines; quercetin-3-glucoside, galactoside, and rhamnoside, and procyanidins, which were higher in F wines.

Characterization of total antioxidant capacity and (poly)phenolic compounds of differently pigmented rice varieties and their changes during domestic cooking

In the recent years, the pigmented rice varieties are becoming more popular due to their antioxidant properties and phenolic content. In this study, we characterized the antioxidant capacity (TAC) and the phenolic profile in white, red and black rice varieties, and evaluated the effect of two cooking methods (i.e. "risotto" and boiling) on these compounds. Before the cooking, all the varieties contained several phenolic acids, whereas anthocyanins and flavonols were peculiar of black rice and flavan-3-ols of red rice. Among the rice varieties, the black had the highest TAC value. The content of (poly)phenolic compounds and TAC decreased after cooking in all three varieties, but to a lesser extent after the risotto method. As a consequence, the risotto cooking, which allows a complete absorption of water, would be a good cooking method to retain (poly)phenolic compounds and TAC in pigmented and non-pigmented whole-meal rice.

Maceration with stems contact fermentation: effect on proanthocyanidins compounds and color in Primitivo red wines

Three Primitivo (Vitis vinifera, cv.) red wines were microvinified by means of different winemaking technologies: no stem-contact fermentation destemming 100% of grapes (D100); stem-contact fermentation destemming 75%, 50% of grapes (D75-D50) respectively. The objectives of this work were to improve proanthocyanidins content in wine, to monitor the relationships between anthocyanins/tannins and to detect the effects on the polymerization state of polyphenols after 12 months storage of wines. D100 showed higher anthocyanins content but lower color intensity and phenolic compounds content with respect to the theses D75 and D50, the last two showing lower anthocyanins content due their partial adsorption by grape stems during the fermentation. D75 gave the best results in terms of anthocyanins/color intensity balance and showed a better wine tannin component with respect to D50. Moreover after 12 months storage D50 reached a more advanced and stable polymerization state of colored pigments than the other wines.

Inhibitory effects of polyphenols from grape pomace extract on collagenase and elastase activity

Breakdown and disorganization of extracellular matrix proteins like collagen, fibronectin and elastin are main characteristics of skin aging due to the enhanced activation of proteolytic enzymes such as collagenases and elastases. Inhibition of their enzymatic activities by natural plant compounds might be a promising approach to prevent extrinsic skin aging. Especially polyphenols are supposed to interact with those enzymes due to their molecular nature. In our investigation, extracts of pomace from Riesling grapes were analyzed for their inhibitory properties on collagenase as well as elastase. Crude grape pomace extract showed a dose-dependent inhibitory activity against both enzymes with IC50-values of 20.3μg/ml and 14.7μg/ml for collagenase and elastase activity, respectively. The extracts were fractionated into four fractions containing phenolic compounds differing in chemical structure and polarity. Except for the stilbene containing fraction, all other fractions showed inhibitory effects on both enzyme activities. The most pronounced impact was found for the hydrophilic low molecular weight polyphenols containing the free phenolic acids. In particular, gallic acid showed considerable inhibition values. EGCG was used as a positive control and showed a dose-dependent inhibition of collagenase activity (IC50=0.9mM).

Pectin plays an important role on the kinetics properties of polyphenol oxidase from honeydew peach

Polyphenol oxidase (PPO) was purified from peach pulp by a three-step column chromatographic procedure. The kinetics properties of the PPO fractions obtained from different purification steps were compared. All the fractions showed high affinities for (+)-catechin and (-)-epicatechin. The optimum pHs and optimum temperatures for all the fractions were the same. However, the fraction that contained pectin was more sensitive to the change of pH, and it had a lower affinity for the substrates and a higher thermostability than the fractions without pectin. In addition, the protein impurities in PPO fractions might have no effect on the properties of PPO. l-Cysteine and glutathione were effective for the inhibition of all the PPO fractions, while NaF inhibited moderately. However, the pectin could reduce the inhibition effects of those inhibitors.