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1.
J Mol Graph Model ; 100: 107690, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32745925

RESUMO

Coronavirus epidemic 2019 (COVID-19), caused by novel coronavirus (2019-nCoV), is newly increasing worldwide and elevating global health concerns. Similar to SARS-CoV and MERS-CoV, the viral key 3-chymotrypsin-like cysteine protease enzyme (3CLPro), which controls 2019-nCoV duplications and manages its life cycle, could be pointed as a drug discovery target. Herein, we theoretically studied the binding ability of 10 structurally different anthocyanins with the catalytic dyad residues of 3CLpro of 2019-nCoV using molecular docking modelling. The results revealed that the polyacylated anthocyanins, including phacelianin, gentiodelphin, cyanodelphin, and tecophilin, were found to authentically bind with the receptor binding site and catalytic dyad (Cys145 and His41) of 2019-nCoV-3CLpro. Our analyses revealed that the top four hits might serve as potential anti-2019-nCoV leading molecules for further optimization and drug development process to combat COVID-19. This study unleashed that anthocyanins with specific structure could be used as effective anti-COVID-19 natural components.


Assuntos
Antocianinas/química , Antivirais/química , Benzopiranos/química , Betacoronavirus/química , Cisteína Endopeptidases/química , Glucosídeos/química , Inibidores de Proteases/química , Proteínas não Estruturais Virais/química , Sequência de Aminoácidos , Betacoronavirus/enzimologia , Sítios de Ligação , Simulação de Acoplamento Molecular , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Alinhamento de Sequência , Relação Estrutura-Atividade , Termodinâmica , Proteínas não Estruturais Virais/antagonistas & inibidores
2.
Food Chem ; 330: 127239, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32540522

RESUMO

Crabapple (Malus prunifolia Willd. Borkh) is a kind of wild apples with many health benefits. However, the utilization of crabapple fruit remains scarce, due to the poor stability of C3G. In this study, C3G loaded nanoparticles were established by chitosan (CS), chitosan oligosaccharides (CSO), and carboxymethyl chitosan (CMC) united with ionic crosslinking agent γ-Polyglutamic acid (PGA) or calcium chloride (CaCl2) to improve the stability of C3G. Results showed that C3G-loaded nanoparticles were exhibited nearly spherical with homogeneous morphology. Particularly, C3G-CMC-CaCl2 nanoparticles exhibited the highest encapsulation efficiency (53.88%) and loading efficiency (5.11%) with preferable particle size (180 nm), good stability (-19 mV) and blood compatibility. C3G-CMC-CaCl2 nanoparticles also revealed the highest releasing ratio (~75%) at pH 5.3 with stability. Present study established the chemical and cell biological basis for further application of C3G-loaded nanoparticles in nutraceutical and functional food fields, extending the application of crabapple in food processing with bioactive enhancement.


Assuntos
Antocianinas/química , Glucosídeos/química , Nanopartículas/química , Quitosana/análogos & derivados , Quitosana/química , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Tamanho da Partícula
3.
Food Chem ; 329: 127157, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32504918

RESUMO

The processing and digestive stability of ethanolic extracts from four Thai rice bran varieties, namely Khao Dawk Mali 105, Hom Nil, Kiaw Ngu, and Leum Pua, were assessed by applying different thermal and pH conditions, as well as in vitro gastrointestinal digestion models. High-performance liquid chromatography, Folin-Ciocalteu analysis, as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) assays were used to determine the chemical composition, total phenolic content (TPC), and antioxidant activity. Thermal treatment at 100 °C for 15 min induced the degradation of phenolic components and TPC, whereas the antioxidant activities measured by DPPH and FRAP assays remained stable after the heat treatment. Higher phenolic content and antioxidant activity values were observed in the extracts incubated at acidic pH levels of 3 and 5. After simulated digestion, all extracts exhibited the decrease of phenolic compounds and anthocyanin contents, as well as antioxidant activities.


Assuntos
Antocianinas/química , Antocianinas/farmacocinética , Oryza/química , Fenóis/química , Fenóis/farmacocinética , Antocianinas/análise , Antioxidantes/análise , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Digestão , Etanol/química , Calefação , Concentração de Íons de Hidrogênio , Fenóis/análise , Extratos Vegetais/química , Tailândia
4.
Food Chem ; 331: 127203, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32574943

RESUMO

Effects of high hydrostatic pressure (HHP) (50, 100, 150, 200 and 250 MPa) pretreatment on water mobility and distribution, drying duration, microstructure, color, cell wall fraction and tissue structure of strawberry slices were investigated. HHP significantly increased water mobility of the strawberry slices, resulting in the reduction of drying duration by 9-24%. As the pretreatment pressure was increased, redness value and anthocyanin content continuously increased, soluble pectin (SBP) content increased and then decreased, while the contents of protopectin (PTP) and cellulose decreased. After the HHP pretreatment, chromoplasts and moisture was distributed more uniformly in the strawberry slices. Microscopy images showed the formation of microscopic holes or channels in the matrix and the breakdown of tissue structure by HHP. Results suggested HHP pretreatment disrupted the integrity of the fresh strawberry which enhanced the drying efficiency and migration of the chromoplasts during the vacuum-freeze drying process.


Assuntos
Fragaria/química , Liofilização , Antocianinas/química , Antocianinas/metabolismo , Celulose/química , Cor , Fragaria/metabolismo , Pressão Hidrostática , Espectroscopia de Ressonância Magnética , Pectinas/química , Pectinas/metabolismo , Água/química
5.
J Food Sci ; 85(6): 1717-1724, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32406950

RESUMO

This study evaluated the influence of different fluidized-bed drying temperatures (20, 60, and 100 °C) on the cooking properties, in vitro starch digestibility, and phenolic bioaccessibility of black rice. The results indicated that the formation of fissures in the grains dried at or above 60 °C reduced the physical integrity of the grains after cooking, increasing the starch digestion and the rehydration ratio, and reduced the cooking time, the hardness and adhesiveness. Due to the higher digestibility of grains dried at higher temperatures, an increase in the bioaccessibility of ferulic acid, which was previously associated with the polysaccharides, was observed. Caffeic acid was the only phenolic compound whose levels decreased when the drying temperature increased. At high temperatures and in the gastric phase, cyanidin chalcones were formed due to the deglycosylation of cyanidin-3-O-glucoside. PRACTICAL APPLICATION: The results of this study provide information to the food industry about the effects of different fluidized-bed drying temperatures on the rice structure after cooking and that, consequently, affect the availability of bioactive compounds after digestion and the glycemic index of black rice.


Assuntos
Dessecação/métodos , Oryza/química , Fenóis/química , Amido/química , Antocianinas/química , Antocianinas/metabolismo , Culinária , Digestão , Manipulação de Alimentos , Glucosídeos/química , Glucosídeos/metabolismo , Índice Glicêmico , Humanos , Modelos Biológicos , Oryza/metabolismo , Fenóis/metabolismo , Amido/metabolismo , Temperatura
6.
Food Chem ; 326: 126904, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413765

RESUMO

In this paper, the interaction of silkworm pupae protein (SPP) with cyanidin-3-O-glucoside (C3G) was studied the protective anthocyanins stability. Characterization experiments suggested that C3G-SPP complexes mainly through hydrophobic interactions, with a decrease in the α-helix content and increases in the ß-sheet and ß-turn contents. Fluorescence results revealed that C3G quenched the intrinsic fluorescence of SPP by static quenching. The highest quenching constant, Kq, was recorded to be1.26 × 1012 M-1s-1 for the SPP preheated at 80 °C. Following the C3G-SPP complexes, the degradation rate constant decreased, and the half-life of C3G was prolonged from 64.81 ± 1.07 to 261.99 ± 13.32 min at 80 °C (p < 0.05). The SPP preheated at 80 °C exhibited the highest binding affinity towards C3G and also effectively increased the thermal and oxidative stability of the C3G. The obtained results suggest that the novel protein proposed in this study could expand the application of anthocyanins as stable, functional food ingredients.


Assuntos
Antocianinas/química , Bombyx/química , Glucosídeos/química , Pupa/química , Animais , Interações Hidrofóbicas e Hidrofílicas , Espectrometria de Fluorescência
7.
Food Chem ; 326: 126977, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32447161

RESUMO

Changes in sensorial, chemical and microbiological qualities of kefirs fortified with black carrot (KBCJ), black mulberry (KBMJ), pomegranate (KPJ), and strawberry (KSJ) juices at different concentrations (10, 25 and 50%, w/w) were monitored throughout storage at 4 °C for 12 weeks. The most preferred kefirs by the sensorial panel were KSJ and KPJ, followed by KBMJ and KBCJ. KBMJ was associated with the highest anthocyanin stability, followed by KPJ, KSJ, and KBCJ. Lactic acid [r = (-0.688)-(-0.970)], glucose [r = (-0.563)-(-0.793)] and microorganisms [r = (-0.633)-(-0.961)] in kefirs had significant effect on anthocyanin stability and colour (p < 0.05). Copigmentation between lactic acid and anthocyanins were observed. Fortification with 25% juices led to an increase (1.8-4.8 times) in antioxidant activity (AA). Shelf-lives of samples, except for KPJ, ended after 12 weeks of storage, due to low sensorial scores. Additions of SJ, PJ and BMJ at 25% concentration are recommended for the production of more palatable kefir with high AA.


Assuntos
Antocianinas/química , Armazenamento de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Kefir/análise , Antocianinas/metabolismo , Antioxidantes/química , Temperatura Baixa , Cor , Concentração de Íons de Hidrogênio , Cinética , Ácido Láctico/química
8.
Food Chem ; 326: 126960, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413752

RESUMO

In this study, intermolecular copigmentation between five primary wine monoglucosidic anthocyanins (cyanidin-3-O-glucoside, peonidin-3-O-glucoside, delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and malvidin-3-O-glucoside) and three common wine phenolics (gallic acid, (-)-epicatechin, and quercetin-3-O-glucoside) were investigated through experimental and theoretical methods, and the influence of substituent pattern of anthocyanin B ring was studied emphatically. Chromatic and thermodynamic analysis showed there were great differences among these different pigment-copigment systems. Spatial conformations of the 15 copigmentation complexes were obtained through theoretical calculation, and diverse π-π stacking modes were observed. These results indicated that the substituent pattern of anthocyanin B ring had significant impact on its affinity to copigments, and more, the structures of pigments and copigments determined the color expression and stability of copigmentation together.


Assuntos
Antocianinas/química , Fenóis/química , Vinho/análise , Antocianinas/análise , Cor , Glucosídeos/análise , Estrutura Molecular , Quercetina/análogos & derivados , Quercetina/análise
9.
Food Chem ; 322: 126767, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32330787

RESUMO

Due to the lack of innovative valorization strategies, berry pomaces are a poorly utilized as a cheap source of valuable nutrients and phytochemicals. An effective biorefining scheme was developed to recover functional components from lingonberry pomace by consecutive supercritical CO2 (SFE-CO2), pressurized liquid (PLE) and enzyme assisted (EAE) extractions. SFE-CO2 at optimized parameters yielded 11.8 g/100 g of lipophilic fraction, containing 43.3 and 37.4% of α-linolenic and linoleic fatty acids, respectively. The combined PLE with ethanol and water additionally recovered 61.8 g/100 g of polar constituents and reduced the antioxidant capacity of starting material by up to 94%. The major portion of the antioxidants (89-94% in different assays), anthocyanins (231 mg/100 g pomace) and proanthocyanidins (15.9 g/100 g pomace) was present in PLE-EtOH extract. Cyanidin-3-galactoside was the major anthocyanin (146.9 mg/100 g). High-pressure fractionation was more efficient for obtaining bioactive pomace constituents as compared with conventional and enzyme-assisted extractions.


Assuntos
Fracionamento Químico/métodos , Solventes/química , Vaccinium vitis-Idaea , Gerenciamento de Resíduos/métodos , Antocianinas/análise , Antocianinas/química , Antioxidantes/análise , Antioxidantes/química , Dióxido de Carbono/química , Etanol/química , Frutas/química , Galactosídeos/análise , Galactosídeos/química , Química Verde , Resíduos Industriais , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Pressão , Proantocianidinas/análise , Proantocianidinas/química , Água
10.
Food Chem ; 320: 126655, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32224423

RESUMO

The effects of ß-cyclodextrin (ß-CD), whey protein (WP), and soy protein (SP) on the color loss and degradation of anthocyanins in purple-fleshed sweet potato anthocyanin extracts (PFSPAEs) during thermal treatment and shelf-life storage in model beverage systems by performing chromaticity, degradation kinetics, and principal component analysis. Results showed that WP and SP improved the thermal stability of the PFSPAE, but WP accelerated the color loss of the extract. However, the addition of 25 mg/L SP improved the color and thermal stability of the anthocyanins when heated at 100 °C for 30 min. With regard to the shelf-life storage, the addition of SP and WP showed non-significant effect on the storage stability of the PFSPAE. However, the addition of 2500 mg/L ß-CD significantly improved the storage stability of the PFSPAE. In summary, our findings provide useful information on improving the thermal and storage stability of PFSPAEs in beverage systems using food biopolymers.


Assuntos
Antocianinas/química , Ipomoea batatas/química , Proteínas de Soja/química , Proteínas do Soro do Leite/química , beta-Ciclodextrinas/química , Antocianinas/análise , Bebidas , Armazenamento de Alimentos , Temperatura Alta
11.
Food Chem ; 320: 126633, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32240924

RESUMO

In winemaking, exogenous tannins are added before maceration to improve future wine color characteristics derived from extracted grape anthocyanins. The study aimed to investigate the relation between different grape varieties, selected according to their anthocyanin profile, and the effect of five exogenous tannin formulations differing in origin and chemical features. Anthocyanin content, polymeric pigments, and color traits were assessed during a 72-hour skin simulated maceration. Grape skin-derived tannins increased color intensity (up to one unit) and polymeric pigments formation (up to 6.5%) in malvidin-prevalent Merlot and Cabernet sauvignon, with different extent depending on the anthocyanin richness. Grape seed-derived and ellagic formulations favored the pigment polymerization, the first in Nebbiolo and Sangiovese (up to 8.2%), which are characterized by high ratios of disubstituted anthocyanins, and the latter in malvidin-rich Syrah and Aglianico (up to 5%). A positive effect of quebracho regarded the defense of anthocyanin forms, particularly in Sangiovese and Nebbiolo.


Assuntos
Antocianinas/química , Taninos/química , Vitis/química , Cor , Frutas/química , Polimerização
12.
Food Chem ; 318: 126449, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32146306

RESUMO

Mulberry and chokeberry are rich sources of anthocyanins. In this study, the effect of the anthocyanin composition on the anthocyanin profile changes during in vitro digestion (mimicking the physiological conditions) was investigated by UHPLC-(ESI)-qTOF and UHPLC-(ESI)-QqQ. The antioxidant activity before and after in vitro digestion was elucidated. Cyanidin-3-O-glucoside and cyanidin-3-O-galactoside were dominant in mulberry and chokeberry, respectively. Moreover, the loss of cyanidin-3-O-galactoside in the chokeberry extract after digestion was greater than that of cyanidin-3-O-glucoside in the mulberry extract. After digestion, phenolic acids including protocatechuic acid and various cyanidin conjugates were newly formed because of decomposition and changes in the cyanidin-glycosides. The phenolic acid and cyanidin conjugate levels varied depending on the cyanidin glycoside sources in the colonic fraction. Finally, antioxidant activity before and after digestion was higher in the chokeberry extract than in the mulberry extract. Moreover, this activity continuously decreased until intestinal digestion but increased in the colonic fraction.


Assuntos
Antocianinas/química , Morus/química , Photinia/química , Antocianinas/metabolismo , Antioxidantes/química , Cromatografia Líquida de Alta Pressão/métodos , Análise por Conglomerados , Digestão , Frutas/química , Frutas/metabolismo , Suco Gástrico/química , Suco Gástrico/metabolismo , Humanos , Espectrometria de Massas/métodos , Morus/metabolismo , Fenóis/análise , Photinia/metabolismo , Extratos Vegetais/química , Análise de Componente Principal
13.
Food Chem ; 318: 126508, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32146312

RESUMO

This work was aimed to obtain lactoferrin peptides, with anthocyanins-binding capabilities, by using eggplant peels extract as a source of anthocyanins. The chromatographic analysis of the extract evidenced the presence of five individual anthocyanins, with delfinidin-3-rutinoside being identified as the predominant. 20 small peptides were identified, from which four are containing Trp at C-terminal. By estimating the thermodynamic parameters, van der Waals and hydrogen bonding were found to have important roles in binding of anthocyanins to LF and LF-derived peptides. In order to complement the experimental results, the in silico methods were further employed to add single molecule level details on the potential interactions between different peptides and the main anthocyanins from eggplant peels. The docking tests indicated that the Trp containing peptides can bind, with different affinities either delphynidine-3-glycoside or delphynidine-3-rutinoside, therefore explaining the fluorescence quenching results. Our results have indicated a mechanism for the interactions between anthocyanins and LF and its small molecular weight peptides, whereas providing insights for formulating ingredients and foods with enhanced bioactives-binding properties.


Assuntos
Antocianinas/química , Lactoferrina/química , Peptídeos/química , Extratos Vegetais/química , Solanum melongena/química , Animais , Bovinos , Fluorescência , Ligação de Hidrogênio , Modelos Moleculares , Simulação de Acoplamento Molecular , Espectrometria de Fluorescência/métodos , Termodinâmica
14.
Food Chem ; 320: 126641, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32213424

RESUMO

The aim of this study was to use acidic electrolyzed water (AEW) to treat longan fruit and evaluate the effects of AEW treatment on storability, quality attributes and nutritive properties of longans during storage. The data indicated that, as compared to the control samples, AEW treatment could effectively reduce the respiration rate and pericarp cell membrane permeability, retard the occurrences of pericarp browning, pulp breakdown and fruit disease, keep a higher rate of commercially acceptable fruit. Additionally, AEW treatment could suppress the decrease of chromaticity values of L*, a* and b* of the fruit surface, keep higher amounts of pericarp carotenoid, chlorophyll, flavonoid and anthocyanin, maintain higher amounts of pulp total soluble solid (TSS), total soluble sugars, sucrose and vitamin C. These results demonstrated that AEW treatment at pH of 2.5, ACC of 80 mg/L could maintain higher quality attributes and nutritive properties, and display better storability of harvested longans.


Assuntos
Sapindaceae/química , Ácidos/química , Antocianinas/química , Eletrólitos , Frutas/química , Água/química
15.
Food Chem ; 320: 126616, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32203835

RESUMO

Egg ovalbumin (OVA) as a prevalent dietary protein and has the potential to serve as a carrier for unstable bioactive compounds, however, understanding their interaction mechanism is the preliminary step. In this work, the interactions between cyanidin-3-O-glucoside (C3G) and OVA in both acidic and neutral pH environment were investigated by spectroscopic methods and molecular docking analysis. The results revealed that fluorescence quenching mechanism of OVA-C3G was predominantly static. The main acting forces were hydrogen bonds and van der Waals forces under varying pH conditions. However, the binding affinity of C3G to OVA was higher in neutral environment than that in acidic condition. The binding of C3G slightly increased the diameter of the complex, resulting in increase of α-helix, decrease of ß-turn, random coil, and total main secondary structure. Moreover, the thermostability of C3G was significantly improved after OVA addition, suggesting its promising application in functional foods.


Assuntos
Antocianinas/química , Glucosídeos/química , Ovalbumina/química , Animais , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Simulação de Acoplamento Molecular , Estrutura Secundária de Proteína , Espectrometria de Fluorescência
16.
J Agric Food Chem ; 68(9): 2783-2794, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32017557

RESUMO

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.


Assuntos
Antocianinas/química , Antioxidantes/química , Glucosídeos/química , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular
17.
Food Chem ; 317: 126418, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32087512

RESUMO

The influence of encapsulation with caseins on the stability of cyanidin 3-O-glucoside (C3G) was investigated. The modified casein nanoparticles (MCs) prepared at pH 5.5 after heated at 80 °C for 30 min was applied to encapsulate C3G. The diameter of nanoparticle (MCs-C3G) was 110 ± 0.31 nm and zeta-potential was -8.83 ± 0.52 mV. The molecular weight of α-casein (32 kDa) and ß-casein (25 kDa) increased along with the encapsulation of C3G. The interactions of MCs with C3G were examined at pH 6.3 by fluorescence spectroscopy and IR spectroscopy. MCs encapsulated C3G mainly via the hydrophobic interaction. The secondary structures of caseins were changed along with the combination of C3G, with a decreasing in α-helix, turn random, and coil structure, as well as increased ß-sheet. In addition, the MCs-C3G interaction appeared to have a positive effect on the thermal, oxidation and photo stability of C3G.


Assuntos
Antocianinas/química , Caseínas/química , Glucosídeos/química , Nanopartículas/química , Estabilidade de Medicamentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Estrutura Secundária de Proteína
18.
J Photochem Photobiol B ; 204: 111800, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32028188

RESUMO

Herein, we have reported the synthesis, characterization and catalytic activity of highly stable gold nanoparticles (Au NPs) using red cabbage extract (RCE) under UV irradiation. The anthocyanin groups predominantly existing in RCE play an essential role for biosynthesis of stable Au NPs. The reasons for using anthocyanins: 1) they act as chelating agents for preferentially reacting with gold ions (Au3+) to form Au3+- anthocyanin complexes, 2) as light-active reductants for reduction of Au3+ to zero valent Au0 under UV irradiation and 3) as stabilizing agent for preventing Au NPs from aggregation in high salt concentration owing to their unique salt tolerance property. We also demonstrate that how reaction time, concentration of RCE, pH value of reaction solutions and using one more reducing agent affected formation of the Au NPs. The stability of RCE Au NPs was comparatively studied with commercial (citrate stabilized) Au NPs against 100 mM salt (NaCl) solution. The RCE-Au NP showed reduction ability for conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). UV-vis spectrometry, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (ZT) methods were utilized to characterize the Au NPs. We demonstrated that how whole RCE (anthocyanins molecules are major component) can be used as photo-active reducing and stabilizing agents to form Au NPs in a short time under UV irradiation and strong reducing agent without additional agents.


Assuntos
Brassica/química , Ouro/química , Nanopartículas Metálicas/química , Raios Ultravioleta , Antocianinas/química , Brassica/metabolismo , Catálise , Química Verde , Nitrofenóis/química , Oxirredução , Extratos Vegetais/química , Sais/química
19.
Artigo em Inglês | MEDLINE | ID: mdl-32066082

RESUMO

Anthocyanins contribute greatly to the organoleptic and biochemical properties of grapes and wines. Although there are broadly documented factors involved in grape anthocyanin synthesis, the present work focused on fungal endophytes and their possible role in grape coloration. Our results showed that exposure to endophytic fungi within a dual culture system differentially affected total anthocyanin concentrations and PAL activities in grape cells. Grape cells dual cultured with fungal strains XH-2, R2-21 and B2-17 showed significant differences of their anthocyanin concentrations were subjected to further analysis of their anthocyanidin compositions. Compared to the no-fungus controls, grape cells exposed to fungal strains XH-2 and R2-21 exhibited quantitative promotion of their total anthocyanidin concentrations by 74% and 28%, respectively, whereas treatment with the fungus B2-17 reduced the anthocyanidin content by 19%. A total of 14 species of anthocyanidins were detected from the grape cells in these experiments. Most interestingly, exposure to any of these fungal strains differentially modified the compositional patterns of grape cellular anthocyanidins. The obvious upregulation of the transcription of VvMYB in grape cells treated with fungal strains XH-2 and R2-21 implies that the increased anthocyanin levels in these grape cells may be due to the activated transcriptional factors. In addition, the exposure of grape cells to extracts of these fungi initiated similar responses of anthocyanin contents and PAL activities to exposure to the living fungi and appeared obvious dosage effects. The influence of fungal endophytes on the coloration of grape berries was also examined in this study.


Assuntos
Antocianinas , Fungos , Vitis , Antocianinas/química , Antocianinas/metabolismo , Frutas/química , Frutas/metabolismo , Frutas/microbiologia , Fungos/fisiologia , Vitis/química , Vitis/metabolismo , Vitis/microbiologia , Vinho
20.
Planta ; 251(3): 60, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32030477

RESUMO

MAIN CONCLUSION: The phosphorylation status of MYB75 at T-131 affects protein stability, flavonoid profiles, and patterns of gene expression. The Arabidopsis transcription factor Myeloblastosis protein 75 (MYB75, AT1G56650) is known to act as a positive transcriptional regulator of genes required for flavonoid and anthocyanin biosynthesis. MYB75 was also shown to negatively regulate lignin and other secondary cell wall biosynthetic genes (Bhargava et al. in Plant Physiol 154(3):1428-1438, 2010). While transcriptional regulation of MYB75 has been described in numerous publications, little is known about post-translational control of MYB75 protein function. In a recent publication, light-induced activation of a MAP kinase (MPK4, AT4G01370) in Arabidopsis was reported to lead to MYB75 phosphorylation at two canonical MPK target sites, threonines, T-126 and T-131. This double phosphorylation event positively influenced MYB75 protein stability (Li et al. in Plant Cell 28(11):2866-2883, 2016). We have examined this phenomenon through use of phosphomutant forms of MYB75 and found that MYB75 is phosphorylated primarily at T-131, and that the phosphorylation of MYB75 recombinant protein in vitro can be catalyzed by multiple MAP kinases, including MPK3 (AT3G45640), MPK6 (AT2G43790), MPK4 and MPK11 (AT1G01560). We also demonstrate that MYB75 can bind to a large number of Arabidopsis MPK's in vitro, suggesting it could be a target of multiple signalling pathways. The impact of MYB75 phosphorylation at T-131 on the function of this transcription factor, in terms of localization, stability, and protein-protein interactions with known binding partners was examined in transgenic lines expressing phosphomimic and phosphonull versions of MYB75, to capture the behaviour of permanently phosphorylated and unphosphorylated MYB75 protein, respectively. In addition, we describe how ectopic over-expression of different phosphovariant forms of MYB75 (MYB75WT, MYB75T131A, and MYB75T131E) affects flavonoid biochemical profiles and global changes of gene expression in the corresponding transgenic Arabidopsis plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição/metabolismo , Antocianinas/biossíntese , Antocianinas/química , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Vias Biossintéticas/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas , Luz , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos , Fosforilação/efeitos da radiação , Plantas Geneticamente Modificadas , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/efeitos da radiação , Estabilidade Proteica/efeitos dos fármacos , Transporte Proteico , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Plântula/efeitos da radiação , Sacarose/farmacologia , Fatores de Transcrição/genética
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