Antioxidant activity of wine pigments derived from anthocyanins: hydrogen transfer reactions to the dpph radical and inhibition of the heme-induced peroxidation of linoleic acid

Effects of Phenolic Evolution on Color Characteristics of Single-Cultivar Vitis vinifera L. Marselan and Merlot Wines during Vinification and Aging

The loss of red hue in dry red wine has been a persistent issue for wine enterprises in western China. We investigated the changes in anthocyanins and non-anthocyanin phenols during the industrial-scale fermentation and one-year bottle aging of Vitis vinifera L. Merlot and Vitis vinifera L. Marselan, respectively, using the grapes in the Ningxia region. We also examined their correlation with color characterization. The study found that both anthocyanins and non-anthocyanin phenolics were rapidly extracted from grapes during alcohol fermentation. However, their concentrations decreased rapidly during malolactic fermentation. On the other hand, Vitisin A and Vitisin B were formed during alcoholic fermentation and decreased slowly from malolactic fermentation to storage period. Directly polymerized pigments (F-A and A-F), bridged polymerized pigments (A-e-F), and flavanyl-pyranoanthocyanins (A-v-F) from the reactions of anthocyanins (A) and flavan-3-ols (F), as well as pinotins were generated during the later stages of alcoholic fermentation, and remained at a high level throughout malolactic fermentation and bottle storage. Partial least squares regression and Pearson correlation analyses revealed that the red hue (a* value) of 'Merlot' and 'Marselan' wines was closely associated with monomeric anthocyanins and F-A type pigments. Furthermore, four pinotin components were positively correlated with the red hue (a* value) of 'Merlot' wine. These primary red components of the two varieties had a positive correlation with the level of flavan-3-ols. The data suggest that elevating the flavan-3-ol concentration during fermentation aids in improving the color stability of red wine.

Enhanced Preservation of Climacteric Fruit with a Cellulose Nanofiber-Based Film Coating

Bananas are a typical climacteric fruit with high respiration and ethylene production rates after harvest, and they show rapid ripening-senescence phenotypes. Here, we demonstrate that carboxymethylcellulose nanofibers (CM-CNFs) and red cabbage extracts (RCE) can be used as a unique film coating formulation for enhancement of the shelf-life of fruit. A CM-CNF suspension solution is created through a process involving chemical modification, followed by mechanical grinding. It has a high aspect ratio that allows for the creation of a thin and transparent film on the surface of bananas. The cross-linked CM-CNF hydrogel forms a dense film layer on the banana surface during dehydration and prevents respiration and weight loss. RCE contains polyphenols acting as antioxidants, which prevent the appearance of black dots on the banana peels. It serves to mitigate the browning of banana skins and also hinders the respiration process, consequently slowing the aging of bananas.

Ti3C2 nanosheets with broad-spectrum antioxidant activity for cytoprotection against oxidative stress

Redox regulation in biological systems represents a fascinating method for treatment and prevention of oxidative stress induced diseases. The key and difficult point is to find ideal materials with excellent antioxidant capability and good biocompatibility. To this end, ultra-thin two-dimensional MXene (Ti3C2) nanosheets (NSs) were investigated for their antioxidant capability. It is found that Ti3C2 NSs can scavenge efficiently reactive oxygen and nitrogen species (˙OH, H2O2, and ˙NO), ABTS+˙ and DPPH˙ free radicals in a concentration dependent manner, showing broad-spectrum antioxidant activities. Ti3C2 NSs exhibit higher antioxidant activity and broader antioxidant capability than natural antioxidant molecules. The significant role of PEG modified Ti3C2 with good stability in preventing cell damage against oxidative stress was demonstrated. Upon treatment of H2O2 induced oxidative stress with Ti3C2, the intracellular ROS level decreases and the cell survival rate increases significantly. An antioxidant mechanism based on gradient oxidation was proposed to account for the superior antioxidant activity of Ti3C2. Our result proves that ultra-thin MXenes as antioxidants have great potential in preventing oxidative stress caused biological damage.

Oxidative Transformation of Dihydroflavonols and Flavan-3-ols by Anthocyanidin Synthase from Vitis vinifera

Twelve polyphenols from three distinct families (dihydroflavonols, flavan-3-ols, and flavanones) were studied as potential substrates of anthocyanidin synthase from Vitis vinifera (VvANS). Only flavan-3-ols of (2R,3S) configuration having either a catechol or gallol group on ring B are accepted as substrates. Only dihydroflavonols of (2R,3R) configuration are accepted as substrates, but a catechol or gallol group is not mandatory. Flavanones are not substrates of VvANS. HPLC and MS/MS analyses of the enzymatic products showed that the VvANS-catalyzed oxidative transformation of (+)-dihydroflavonols, such as dihydroquercetin, dihydrokaempferol and dihydromyricetin, leads only to the corresponding flavonols. Among the flavan-3-ols recognized as substrates, (+)-gallocatechin was only transformed into delphinidin by VvANS, whereas (+)-catechin was transformed into three products, including two major products that were an ascorbate-cyanidin adduct and a dimer of oxidized catechin, and a minor product that was cyanidin. Data from real-time MS monitoring of the enzymatic transformation of (+)-catechin suggest that its products are all derived from the initial C₃-hydroxylation intermediate, i.e., a 3,3-gem-diol, and their most likely formation mechanism is discussed.

Ultrahigh Pressure Facilitates the Acylation of Malvidin and Chlorogenic Acid to Increase the Stability and Protective Effect of Malvidin Derivatives on H2O2-Induced ARPE-19 Cells

We explored the effects of ultrahigh-pressure technology and chlorogenic acid on the color stability and structure-activity relationship of malvidin (MV). Experimental conditions were optimized through single-factor experiments and response surface analysis at a pressure of 300 MPa, mass ratio of MV to chlorogenic acid of 1:3.64 (w/w), and time of 5 min. Compared with MV, MV derivatives showed higher stability and in vitro antioxidant activity. X-ray diffraction analysis, UV-vis spectroscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography, and mass spectrometry were conducted to determine the structures of MV derivatives for the first time. Ultrahigh pressure facilitated acylation of chlorogenic acid and MV and produced four new MV derivatives. Analysis of the effect of malvidin-3-O-6-(acrylic acid-(2-hydroxy, 4-carboxy-cyclohexanol) ester)-guaiacol (Mv3ACEC) on ARPE-19 cells exposed to H₂O₂ by RNA transcriptome sequencing showed that Mv3ACEC simultaneously inhibited various inflammatory and apoptotic signal transduction pathways, exerted a synergistic effect, and partly inhibited cell apoptosis through the MAPK signaling pathway. Therefore, the results show that ultrahigh pressure will cause acylation of chlorogenic acid and MV to produce four new MV derivatives, and MV derivatives protect ARPE-19 cells from H₂O₂-induced oxidative stress.

Malvidin and its derivatives exhibit antioxidant properties by inhibiting MAPK signaling pathways to reduce endoplasmic reticulum stress in ARPE-19 cells

Malvidin (MV) and its derivatives, such as malvidin-3-O-guaiacol (Mv3C) and malvidin-3-O-6-(acrylic acid-(2-hydroxy,4-carboxy-cyclohexanol)ester)-guaiacol (Mv3ACEC), are natural compounds with antioxidant properties. However, the basic mechanisms underlying their functional activities are unclear. In this study, we show that MV, Mv3C, and Mv3ACEC inhibit reactive oxygen species production and malondialdehyde content, promote glutathione peroxidase activity, and increase superoxide dismutase levels in ARPE-19 cells treated with H₂O₂. Western blotting and immunofluorescence analysis revealed that MV, Mv3C, and Mv3ACEC regulate mitogen-activated protein kinase signal transduction pathways related to endoplasmic reticulum stress. Interestingly, Mv3C and Mv3ACEC showed greater beneficial properties than MV. Our results show that MV and its derivatives have potential as therapeutic compounds for ocular diseases associated with oxidative stress, such as age-related macular degeneration.

Advanced characterization of polyphenols from Myrciaria jaboticaba peel and lipid protection in in vitro gastrointestinal digestion

Ultrasound-assisted and solvent extractions resulted in similar levels of hydrolyzable tannins (10.3-6.0 mg/g), anthocyanins (7.8-10.2 mg/g) and flavonols (0.24-0.32 mg/g) for dried Myrciaria jaboticaba peel (DJP). Ultrasound was efficient for the extraction of poorly soluble hydrolyzable tannins but affected the stability of anthocyanins and flavonols. UPLC-DAD-MSⁿ allowed the identification of 44 hydrolyzable tannins as single and mixed hexosides bearing galloyl, HHDP and tergalloyl units. Twelve mixed HHDP-galloylgluconic acids and tergalloylated hexosides were newly discovered in this work. Acid hydrolysis of both ultrasonic extract and DJP yielded five major compounds, i.e. gallic acid, ellagic acid, gallic acid-C-hexoside, valoneic acid dilactone and sanguisorbic acid dilactone and pointed to higher contents in hydrolyzable tannins than by summing individual polyphenols after UPLC. Last, cyanidin-3-O-glucoside and hydrolyzable tannins from the ultrasonic extract inhibited lipid peroxidation of a Western type meal in in vitro digestion, suggesting a health benefit for these jabuticaba polyphenols.

State of the Art of Anthocyanins: Antioxidant Activity, Sources, Bioavailability, and Therapeutic Effect in Human Health

The antioxidant activity of anthocyanins in food is well known. Numerous antioxidant assays have been proposed to measure the capacity of anthocyanins to prevent the oxidation process that naturally occurs. Different solvents, temperatures, and pH levels are applied in each assay, and these factors should be taken into account in order to obtain useful and reproducible results. The concentration and the structure of these compounds are directly related to their antioxidant capacity and their environment. However, the effectiveness of the anthocyanin ingestion against diseases is also influenced by its bioavailability. Novel methodologies that simulate the digestion process have been developed in order to facilitate the current knowledge of anthocyanins bioavailability. Studies highlight the potential synergy effect between parent compounds and their derivatives (metabolites, conjugated products, and microbe-generated metabolites). The aim of this review is to provide an overview of advantages and disadvantages of the most common methods to determine the antioxidant activity of anthocyanins, chemical structure, and concentration of these compounds in different edible fruits, vegetables, and plants; their bioavailability after intake; as well as the main therapeutic effect described in the scientific literature.

Comparative Study on the Stability and Antioxidant Activity of Six Pyranoanthocyanins Based on Malvidin-3-glucoside

Pyranoanthocyanins are the important color and functional compounds in red wine. Six common kinds of pyranoanthocyanins were synthesized through the reaction of malvidin-3-O-glucoside (Mv-3-gluc) with acetone, pyruvic acid, p-cumaric acid, caffeic acid, ferulic acid, and sinapid acid, respectively, and their pH (1.0-11.0), SO₂ (0-250 ppm), and thermo (50-98 °C) stabilities and antioxidant activities were comparatively studied. Results showed that the six pyranoanthocyanins all exhibited higher pH and SO₂ color stability than Mv-3-gluc, especially vitisin-A with a carboxy group on the D ring. The six pyranoanthocyanins also showed much more thermostability than Mv-3-gluc, especially methylpyranomv-3-gluc. The degradation kinetics of Mv-3-gluc and its derivatives all fitted to a first-order reaction. Moreover, pinotin-A with the o-dihydroxyl group on the E ring presented the strongest antioxidant capability, as evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric ion reducing power (FRAP) assays. Additionally, the increase in the number of rings is beneficial to the improvement of the DPPH radical scavenging ability of anthocyanins.

Phenolic Antioxidants in Aerial Parts of Wild Vaccinium Species: Towards Pharmaceutical and Biological Properties

Phenolic compounds are a widespread group of secondary metabolites found in all plants, representing the most desirable antioxidants due to their potential to be used as additives in the food industry (inhibition of lipid oxidation), and in cosmetology and medicine (protection against oxidative stress). In recent years, demand for the identification of edible sources rich in phenolic antioxidants, as well as the development of new natural plant products to be used as dietary supplements or pharmaceuticals, has been a great preoccupation. At present, from the "circular economy" perspective, there is an increased interest to use agricultural waste resources to produce high-value compounds. Vaccinium leaves and stems are considered essentially an agro-waste of the berry industry. Scientific studies have shown that phenolic compounds were found in a markedly higher content in the leaves and stems of Vaccinium plants than in the fruits, in agreement with the strongest biological and antioxidant activities displayed by these aerial parts compared to fruits. This paper aims to review the current state of the art regarding the phenolic antioxidants from leaves and stems of two wild Vaccinium species, bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.), as promising natural resources with pharmaceutical and biological activity.

Oxidative Transformation of Leucocyanidin by Anthocyanidin Synthase from Vitis vinifera Leads Only to Quercetin

Anthocyanidin synthase from Vitis vinifera ( VvANS) catalyzes the in vitro transformation of the natural isomer of leucocyanidin, 2 R,3 S,4 S- cis-leucocyanidin, into 2 R,4 S-flavan-3,3,4-triol ([M + H]⁺, m/ z 323) and quercetin. The C₃-hydroxylation product 2 R,4 S-flavan-3,3,4-triol is first produced and its C₃,C₄-dehydration product is in tautomeric equilibrium with (+)-dihydroquercetin. The latter undergoes a second VvANS-catalyzed C₃-hydroxylation leading to a 4-keto-2 R-flavan-3,3-gem-diol which upon dehydration gives quercetin. The unnatural isomer of leucocyanidin, 2 R,3 S,4 R- trans-leucocyanidin, is similarly transformed into quercetin upon C₃,C₄-dehydration, but unlike 3,4- cis-leucocyanidin, it also undergoes some C₂,C₃-dehydration followed by an acid-catalyzed hydroxyl group extrusion at C₄ to give traces of cyanidin. Overall, the C₃,C₄- trans isomer of leucocyanidin is transformed into 2 R,4 R-flavan-3,3,4-triol (M + 1, m/ z 323), (+)-DHQ, (-)-epiDHQ, quercetin, and traces of cyanidin. Our data bring the first direct observation of 3,4- cis-leucocyanidin- and 3,4- trans-leucocyanidin-derived 3,3-gem-diols, supporting the idea that the generic function of ANS is to catalyze the C₃-hydroxylation of its substrates. No cyanidin is produced with the natural cis isomer of leucocyanidin, and only traces with the unnatural trans isomer, which suggests that anthocyanidin synthase requires other substrate(s) for the in vivo formation of anthocyanidins.

The Chemical Reactivity of Anthocyanins and Its Consequences in Food Science and Nutrition

Owing to their specific pyrylium nucleus (C-ring), anthocyanins express a much richer chemical reactivity than the other flavonoid classes. For instance, anthocyanins are weak diacids, hard and soft electrophiles, nucleophiles, prone to developing π-stacking interactions, and bind hard metal ions. They also display the usual chemical properties of polyphenols, such as electron donation and affinity for proteins. In this review, these properties are revisited through a variety of examples and discussed in relation to their consequences in food and in nutrition with an emphasis on the transformations occurring upon storage or thermal treatment and on the catabolism of anthocyanins in humans, which is of critical importance for interpreting their effects on health.

Red Wine and Pomegranate Extracts Suppress Cured Meat Promotion of Colonic Mucin-Depleted Foci in Carcinogen-Induced Rats

Processed meat intake is carcinogenic to humans. We have shown that intake of a workshop-made cured meat with erythorbate promotes colon carcinogenesis in rats. We speculated that polyphenols could inhibit this effect by limitation of endogenous lipid peroxidation and nitrosation. Polyphenol-rich plant extracts were added to the workshop-made cured meat and given for 14 days to rats and 100 days to azoxymethane-induced rats to evaluate the inhibition of preneoplastic lesions. Colons of 100-d study were scored for precancerous lesions (mucin-depleted foci, MDF), and biochemical end points of peroxidation and nitrosation were measured in urinary and fecal samples. In comparison with cured meat-fed rats, dried red wine, pomegranate extract, α-tocopherol added at one dose to cured meat and withdrawal of erythorbate significantly decreased the number of MDF per colon (but white grape and rosemary extracts did not). This protection was associated with the full suppression of fecal excretion of nitrosyl iron, suggesting that this nitroso compound might be a promoter of carcinogenesis. At optimized concentrations, the incorporation of these plant extracts in cured meat might reduce the risk of colorectal cancer associated with processed meat consumption.

Theoretical and Kinetic Tools for Selecting Effective Antioxidants: Application to the Protection of Omega-3 Oils with Natural and Synthetic Phenols

Radical-scavenging antioxidants play crucial roles in the protection of unsaturated oils against autoxidation and, especially, edible oils rich in omega-3 because of their high sensitivity to oxygen. Two complementary tools are employed to select, among a large set of natural and synthetic phenols, the most promising antioxidants. On the one hand, density functional theory (DFT) calculations provide bond dissociation enthalpies (BDEs) of 70 natural (i.e., tocopherols, hydroxybenzoic and cinnamic acids, flavonoids, stilbenes, lignans, and coumarins) and synthetic (i.e., 2,6-di-tert-butyl-4-methylphenol (BHT), 3-tert-butyl-4-hydroxyanisol (BHA), and tert-butylhydroquinone (TBHQ)) phenols. These BDEs are discussed on the basis of structure-activity relationships with regard to their potential antioxidant activities. On the other hand, the kinetic rate constants and number of hydrogen atoms released per phenol molecule are measured by monitoring the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) radical. The comparison of the results obtained with these two complementary methods allows highlighting the most promising antioxidants. Finally, the antioxidant effectiveness of the best candidates is assessed by following the absorption of oxygen by methyl esters of linseed oil containing 0.5 mmol L(-1) of antioxidant and warmed at 90 °C under oxygen atmosphere. Under these conditions, some natural phenols namely epigallocatechin gallate, myricetin, rosmarinic and carnosic acids were found to be more effective antioxidants than α-tocopherol.

Chemically synthesized glycosides of hydroxylated flavylium ions as suitable models of anthocyanins: binding to iron ions and human serum albumin, antioxidant activity in model gastric conditions

Polyhydroxylated flavylium ions, such as 3',4',7-trihydroxyflavylium chloride (P1) and its more water-soluble 7-O-β-d-glucopyranoside (P2), are readily accessible by chemical synthesis and suitable models of natural anthocyanins in terms of color and species distribution in aqueous solution. Owing to their catechol B-ring, they rapidly bind FeIII, weakly interact with FeII and promote its autoxidation to FeIII. Both pigments inhibit heme-induced lipid peroxidation in mildly acidic conditions (a model of postprandial oxidative stress in the stomach), the colorless (chalcone) forms being more potent than the colored forms. Finally, P1 and P2 are moderate ligands of human serum albumin (HSA), their likely carrier in the blood circulation, with chalcones having a higher affinity for HSA than the corresponding colored forms.

Antioxidant features of red wine pyranoanthocyanins: experimental and theoretical approaches

This work is focused on the study of the antioxidant properties of red wine anthocyanin derivatives (carboxypyranoanthocyanins, methylpyranoanthocyanins, oxovitisins, and pyranoanthocyanin-phenolics) derived from malvidin-3-glucoside. Some antioxidant features were determined using the DPPH assay and the ability to delay lipid peroxidation in a liposome membrane system by monitoring oxygen consumption. The pyranoanthocyanin-phenolics have higher antioxidant potential than that of malvidin-3-glucoside, suggesting that the addition of a catechol or flavanol moiety increases the antioxidant capacity. The only derivatives that showed lower antioxidant features than malvidin-3-glucoside were oxovitisins and methylpyranomalvidin-3-glucoside. Also, the radical scavenging capacity of these pyranoanthocyanins was computationally explored using DFT methods. All pyranoanthocyanins were suggested as good candidates as antioxidant compounds because they easily donate an H atom to the free radicals, originating stable species. Altogether, these results support the fact that the antioxidant potential arising from anthocyanins is not impaired by some of their transformations during red wine aging.

Dietary anthocyanin-rich Haskap phytochemicals inhibit postprandial hyperlipidemia and hyperglycemia in rats

Haskap (Lonicera caerulea L.) fruit contains some bioactive phenolic phytochemicals, mainly cyanidin-3-glucoside (cy3-glc) and chlorogenic acid. The purpose of this study was to investigate the effects of anthocyanin-rich phenolic phytochemical (containing 13.2% anthocyanin) purified from a Haskap fruit (named Haskap phytochemical) on postprandial serum triglyceride and blood glucose levels. The Haskap phytochemical (containing cy 3-glc at 300 mg/kg of body weight) was administered orally to rats fasted for 24 h and 30 min later, a corn oil emulsion was administered to these rats. After the administration, serum triglyceride concentration was measured. An increase in serum triglyceride concentration and the AUC significantly lowered in the Haskap phytochemical-administered group than in the saline-administered group. To evaluate the effect of serum glucose levels, the Haskap phytochemical was orally administered to rats fasted for 24 h and sucrose solution (2 g/kg of body weight) was administered to these rats after 30 min. After the administration, blood glucose level was measured. The Haskap phytochemical significantly reduced the increase in blood glucose levels and AUC in the Haskap phytochemical-administered group than in the saline-administered group. Furthermore, to investigate the long-term effects of Haskap phytochemical intake, high-fat diet (HF diet) with 1.5% or 3.0% Haskap phytochemical was administered to rats for four weeks. The investigation of chronological changes in the serum components of the rats fed HF diets in addition to the administration of Haskap phytochemical showed that the increase in serum triglyceride concentrations, total cholesterol concentrations and blood glucose were significantly suppressed compared to the HF diet-fed control (HF-control). These results suggest that the decrease in postprandial blood lipids and blood glucose by short or long-term Haskap phytochemical ingestion is due to anthocyanin and other polyphenols contained in the Haskap phytochemical.

Grape polyphenols increase the activity of HDL enzymes in old and obese rats

HDL particles are protein-rich particles that act as a vehicle for reverse cholesterol transport from tissues to the liver. The purpose of this study was to investigate age-dependent changes in the functional activity of HDL and the effect of high-energy diet on this index, as well as to correct it under the influence of grape polyphenols from “Enoant” obtained from Vitis vinifera grapes. We observed the age-dependent composition changes in HDL particle. It was shown that total lipids and triacylglycerol (TG) levels were higher in 24-month-old animals. In obese rats, HDL total lipids and TG levels were higher in 24-month-old than in the 3-month-old and 12-month-old groups but did not differ from 24-month-old group. The plasma HDL paraoxonase (PON) and lecithin:cholesterol acyltransferase (LCAT) activity levels were decreased in old-aged rats, and cholesteryl ester transfer protein (CETP) activity was higher in old rats. Keeping 12-month-old animals on high-fructose diet completely leveled the age differences in the data that have been measured between 12-month-old and 24-month-old rats. After “Enoant” administration, an increase of HDL PON and LCAT activity levels and a reduction of CETP activity were found in 24-month-old and obese rats.

Antioxidant and Antimicrobial activity of Pedicularis sibthorpii Boiss. And Pedicularis wilhelmsiana Fisch ex

PURPOSE

This research paper presents antioxidant and antimicrobial activities of Pedicularis sibthorpii and Pedicularis wilhelmsiana which grow in Azerbaijan/Iran with claimed a lot of therapeutic effects.

METHODS

DPPH assay and agar well diffusion method were carried out to determine antioxidant and antimicrobial activities respectively.

RESULTS

Methanolic extract showed better antioxidant activity compared to other crude extracts (n-hexane and dichloromethane). Methanolic extracts of both Pedicularis sibthorpii and Pedicularis wilhelmsiana were found to have antibacterial activity especially against gram positive strains of S. ureus, S.epidermidis. No antifungal activity was observed in the tested extracts.

CONCLUSION

Existence of some phenolic compounds in methanolic extracts, such as phenylethanoids and flavonoids (found in other species of Pedicularis), which cause both antioxidant and antibacterial activities, is probable. Antimicrobial and antioxidant activity of the methanolic extracts supports further studies related to phytochemical investigation and bioassay of different fractions to isolate pure compounds of plants.

Comparative study on antioxidant activity of lycopene (Z)-isomers in different assays

Several studies have implicated the potent antioxidant properties of lycopene. However, most of the studies used only the (all-E)-isomer. (Z)-Isomers of lycopene were found in substantial amounts in processed foods and in human tissues. In the present study, we investigated in vitro the antioxidant activity of (5Z)-, (9Z)-, and (13Z)-lycopene compared to the (all-E)-isomer. Additionally, prolycopene, the (7Z,9Z,7'Z,9'Z)-isomer found in tangerine tomatoes, was analyzed. No significant differences were found between the isomers in ferric reducing antioxidant power assay and in bleaching the radical cation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), both based on ET mechanisms. In contrast, scavenging activity against peroxyl radicals generated by thermal degradation of 2,2'-azobis(2-amidinopropane) (AAPH) was higher in the (Z)-isomers. (5Z)-Lycopene was most antioxidant in scavenging lipid peroxyl radicals, evaluated by analyzing the inhibition of MbFe(III) lipid peroxidation of linoleic acid in mildly acidic conditions (pH 5.8) in a micellar environment, modeling a possible antioxidant action in the gastric compartment.

Optimization of ultrasound-assisted extraction of anthocyanins from mulberry, using response surface methodology

Mulberry is one of the most widely used traditional Chinese medicines. Anthocyanins are the main bioactive components of mulberry, and possess important biological activities, such as antimicrobial, anti-inflammatory and antioxidant activities. This study investigated the ultrasound-assisted extraction (UAE) of anthocyanins from mulberry by using response surface methodology (RSM). The extraction conditions associated with anthocyanin yield, including extraction solvent, liquid-to-solid rate, temperature and extraction time, are discussed. The optimal conditions obtained by RSM for UAE from mulberry include 63.8% methanol contains 1% (v/v) trifluoroacetic acid (TFA), 43.2 °C temperature, 23.8 (v/w) liquid-to-solid ratio, and 40 min time for the maximum yield (64.70 ± 0.45 mg/g). The results indicated that the UAE can be an effective method for the extraction of some active components from plant materials.

Cyanidin-3-O-β-glucoside with the aid of its metabolite protocatechuic acid, reduces monocyte infiltration in apolipoprotein E-deficient mice

Polyphenols, including anthocyanins, from various plant foods are effective in reducing the severity of atherosclerosis in animal and human studies. Due to the poor understanding of the bioavailability of anthocyanins, the potential antiatherogenic mechanisms underlying the action remain largely unknown. Herein, we found that oral gavage of cyanidin-3-O-β-glucoside (Cy-3-G) could be transformed into protocatechuic acid (PCA), and the plasma maximal levels of Cy-3-G were 3.7-fold lower than that of PCA in the apolipoprotein E (ApoE)-deficient mice. Subsequently, we observed that PCA treatment has a higher capacity than Cy-3-G treatment in decreasing CC chemokine receptor 2 (CCR2) expression in the mouse peripheral blood monocytes (PBMs), along with reducing the mouse PBMs chemokine toward CC ligand-2 (CCL2) in a Boyden chamber. Interesting, in the ApoE-deficient mouse model, orally gavaged with Cy-3-G has a higher ability than gavaged with PCA to reduce CCR2 expression in PBMs. PBMs deprived from the Cy-3-G-treated ApoE-deficient mice have a lower ability than those from PCA-treated animals to migrate toward CCL2. Furthermore, as compared with the PCA group, Cy-3-G treatment more efficiently reduced thioglycollate-induced macrophage infiltration into the abdominal cavity. Thus, we suggest that Cy-3-G may reduce the monocyte infiltration in mice via down-regulation of CCR2 expression in monocytes, at least in part, with the aid of its metabolite PCA. These above data imply that the anti-monocyte/macrophage infiltration property of Cy-3-G and its metabolite PCA may be an important antiatherogenic mechanism for anthocyanins.

Plant polyphenols: chemical properties, biological activities, and synthesis

Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.