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1.
Sci Rep ; 11(1): 2043, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479401

RESUMO

The recent outbreak of the coronavirus (SARS-CoV2) is an unprecedented threat to human health and society across the globe. In this context, development of suitable interventions is the need of the hour. The viral spike protein (S Protein) and the cognate host cell receptor ACE2 can be considered as effective and appropriate targets for interventions. It is evident from the present computational study, that catechin and curcumin, not only exhibit strong binding affinity to viral S Protein and host receptor ACE2 but also to their complex (receptor-binding domain (RBD) of the spike protein of SARS-CoV2 and ACE2; RBD/ACE2-complex). The binding affinity values of catechin and curcumin for the S protein, ACE2 and RBD/ACE2-complex are - 10.5 and - 7.9 kcal/mol; - 8.9 and - 7.8 kcal/mol; and - 9.1 and - 7.6 kcal/mol, respectively. Curcumin directly binds to the receptor binding domain (RBD) of viral S Protein. Molecular simulation study over a period of 100 ns further substantiates that such interaction within RBD site of S Protein occurs during 40-100 ns out of 100 ns simulation trajectory. Contrary to this, catechin binds with amino acid residues present near the RBD site of S Protein and causes fluctuation in the amino acid residues of the RBD and its near proximity. Both catechin and curcumin bind the interface of 'RBD/ACE2-complex' and intervene in causing fluctuation of the alpha helices and beta-strands of the protein complex. Protein-protein interaction studies in presence of curcumin or catechin also corroborate the above findings suggesting the efficacy of these two polyphenols in hindering the formation of S Protein-ACE2 complex. In conclusion, this computational study for the first time predicts the possibility of above two polyphenols for therapeutic strategy against SARS-CoV2.


Assuntos
/metabolismo , Catequina/metabolismo , Curcumina/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , /metabolismo , Catequina/química , Catequina/farmacologia , Membrana Celular/metabolismo , Biologia Computacional/métodos , Curcumina/química , Curcumina/farmacologia , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química
2.
Food Chem ; 338: 128048, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950869

RESUMO

In this study, theaflavins were used to interact with bovine lactoferrin (bLF) to observe the effects of theaflavins on the structure and functionality of bLF. Spectral experiments verified that theaflavins were able to interact with bLF by a static quenching method. The circular dichroism experiment further showed that the combination of theaflavins would lead a certain change in the structure of bLF. By comparing the calculated data of the spectral experiment and the degree of structural change after bLF binding to theaflavins, the theaflavin-3, 3'-digallate (TFDG), which had the strongest effect on the structure of bLF, was selected to explore its influence on effects of bLF functionality. Conclusions were drawn from iron binding, enzyme-linked immunosorbent and in vitro simulated digestion experiments-the addition of TFDG had a certain effect on the functionality of bLF.


Assuntos
Biflavonoides/química , Catequina/química , Lactoferrina/química , Sequência de Aminoácidos , Animais , Antioxidantes/química , Biflavonoides/metabolismo , Sítios de Ligação , Catequina/metabolismo , Bovinos , Dicroísmo Circular , Imunoglobulina E/química , Imunoglobulina E/metabolismo , Ferro/química , Ferro/metabolismo , Lactoferrina/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica
3.
Food Chem ; 339: 128145, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33152895

RESUMO

The solution turbidity and intrinsic fluorescence quenching increased after procyanidin was mixed with lactoferrin. The addition of procyanidin also caused a reduction in the surface hydrophobicity of the lactoferrin, suggesting procyanidin bound to non-polar patches on lactoferrin's surfaces. Moreover, the binding interaction caused an appreciable alteration in the structure of both the polyphenol and protein. Thermodynamic analysis indicated the interaction was spontaneous and mainly driven by entropy changes, suggesting that hydrophobic interactions dominated. A computational docking simulation provided insights into the location of the most-likely binding sites on the protein, as well as the nature of the interaction forces involved. In particular, both hydrophobic and hydrogen bonding were found to be important. The binding of the procyanidin to the lactoferrin enhanced its foaming properties. These results may lead to the development of a new class of natural functional ingredients that can be used in food products to improve their quality attributes.


Assuntos
Biflavonoides/química , Catequina/química , Lactoferrina/química , Proantocianidinas/química , Animais , Biflavonoides/metabolismo , Sítios de Ligação , Catequina/metabolismo , Bovinos , Fluorescência , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Lactoferrina/metabolismo , Simulação de Acoplamento Molecular , Proantocianidinas/metabolismo , Espectrometria de Fluorescência , Termodinâmica
4.
PLoS One ; 15(8): e0237017, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32756588

RESUMO

Procyandin A2 (PCA2) is a polyphenolic compound which is isolated from grape seeds. It has been reported that PCA2 exhibits antioxidative and anti-inflammatory effects, but its molecular mechanism is still poorly understood. This study tests the hypothesis that PCA2 suppresses lipopolysaccharide (LPS)-induced inflammation and oxidative stress through targeting the nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and NF-E2-related factor 2 (Nrf2) pathways in RAW264.7 cells. PCA2 (20, 40, 80 µM) exhibited no significant cytotoxicity in RAW264.7 cells and showed an inhibitory effect on an LPS-induced nitrite level. Pro-inflammatory cytokines like tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE2), nitric oxide (NO), and reactive oxygen species (ROS) were suppressed by PCA2 with a concentration range of 0-80 µM. The mRNA levels of TNF-α and IL-6 were inhibited by PCA2 (80 µM). The hallmark-protein expression of the NF-κB (p-IKKα/ß, p-IκBα, and p-p65) and MAPK (p-p38, p-JNK, and p-ERK) pathways were decreased by PCA2 in LPS-stimulated RAW264.7 cells. In addition, immunofluorescence results indicated that PCA2 (80 µM) promoted the translocation of NF-κB/p65 from the cytoplasm into the nucleus. PCA2 upregulated the expressions of Nrf2 and HO-1 and downregulated the expression of Keap-1. Simultaneously, PCA2 (80 µM) reversed LPS-induced Nrf2 translocation from the nucleus into the cytoplasm. Collectively, PCA2 protect cells against the damage from inflammation and oxidative injury, which suggest a potential therapeutic strategy for inflammatory and oxidative stress through targeting NF-κB, MAPK, and Nrf2 pathways in RAW264.7 cells.


Assuntos
Catequina/metabolismo , Catequina/farmacologia , Inflamação/tratamento farmacológico , Proantocianidinas/metabolismo , Proantocianidinas/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Citocinas/metabolismo , Dinoprostona/metabolismo , Heme Oxigenase-1/metabolismo , Lipopolissacarídeos/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/efeitos dos fármacos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fator 2 Relacionado a NF-E2/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Inibidor de NF-kappaB alfa/metabolismo , NF-kappa B/efeitos dos fármacos , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos
5.
Life Sci ; 259: 118260, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32795541

RESUMO

Cigarette smoke (CS), the major risk factor of chronic obstructive pulmonary disease (COPD), contains numerous free radicals that can cause oxidative stress and exaggerated inflammatory responses in the respiratory system. Lipid peroxidation which is oxidative degradation of polyunsaturated fatty acids and results in cell damage has also been associated with COPD pathogenesis. Increased levels of lipid peroxidation as well as its end product 4-hydroxynonenal have indeed been detected in COPD patients. Additionally, reactive oxygen species such as those contained in CS can activate nuclear factor-κB signaling pathway, initiating cascades of proinflammatory mediator expression. As emerging evidence attests to the antioxidative and anti-inflammatory properties of tea catechins, we sought to determine whether epigallocatechin gallate, the most abundant tea catechin, can provide protection against oxidative stress, lipid peroxidation, and inflammatory responses caused by CS. We found that EGCG treatment blocked cigarette smoke extract (CSE)-induced oxidative stress as indicated by decreased production and accumulation of reactive oxygen species in airway epithelial cells (AECs). Likewise, lipid peroxidation in CSE-stimulated AECs was suppressed by EGCG. Our findings further suggest that EGCG sequestered 4-hydroxynonenal and interfered with its protein adduct formation. Lastly, we show that EGCG inhibited nuclear factor-κB activation and the downstream expression of proinflammatory mediators. In summary, our study describing the antioxidative and anti-inflammatory effects of EGCG in CSE-exposed AECs provide valuable information about the therapeutic potential of this tea catechin for COPD.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Catequina/análogos & derivados , Fumar Cigarros/tratamento farmacológico , Aldeídos/farmacologia , Células Epiteliais Alveolares/metabolismo , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Brônquios/metabolismo , Catequina/metabolismo , Catequina/farmacologia , Linhagem Celular , Fumar Cigarros/efeitos adversos , Fumar Cigarros/fisiopatologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Inflamação/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , NF-kappa B/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Espécies Reativas de Oxigênio , Transdução de Sinais/efeitos dos fármacos , Fumaça/efeitos adversos , Fumar/efeitos adversos
6.
Nat Commun ; 11(1): 3719, 2020 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709943

RESUMO

Wild teas are valuable genetic resources for studying domestication and breeding. Here we report the assembly of a high-quality chromosome-scale reference genome for an ancient tea tree. The further RNA sequencing of 217 diverse tea accessions clarifies the pedigree of tea cultivars and reveals key contributors in the breeding of Chinese tea. Candidate genes associated with flavonoid biosynthesis are identified by genome-wide association study. Specifically, diverse allelic function of CsANR, CsF3'5'H and CsMYB5 is verified by transient overexpression and enzymatic assays, providing comprehensive insights into the biosynthesis of catechins, the most important bioactive compounds in tea plants. The inconspicuous differentiation between ancient trees and cultivars at both genetic and metabolic levels implies that tea may not have undergone long-term artificial directional selection in terms of flavor-related metabolites. These genomic resources provide evolutionary insight into tea plants and lay the foundation for better understanding the biosynthesis of beneficial natural compounds.


Assuntos
Variação Genética , Genoma de Planta , Melaleuca/genética , Linhagem , Árvores/genética , Alelos , Vias Biossintéticas/genética , Camellia sinensis/genética , Catequina/metabolismo , China , Domesticação , Evolução Molecular , Ácido Gálico/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Estudo de Associação Genômica Ampla , Genômica , Análise de Sequência de RNA , Óleo de Melaleuca
7.
Food Chem ; 333: 127432, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32659661

RESUMO

The sensory qualities and shelf life of tea beverage strongly affected by tea cream that forms by the interaction of polyphenols and protein. The study aimed to investigate the effects of the interactions between tea polyphenols (TPs) and bovine serum albumin (BSA) on tea cream formation at different concentrations. The tea cream formation increased with TPs and BSA concentration increased. The optimal concentration (TPs: 800 mg/L, BSA: 40 mg/L), for high clarities and contents of phytochemicals, was selected by the technique for order preference by similarity to ideal solution (C = 0.7572). The interaction mechanism of TPs-BSA was investigated by fluorescence spectroscopy, UV-visible absorption spectroscopy, synchronous fluorescence spectroscopy, and molecular docking. TPs interacted with BSA via static quenching process, affecting tryptophan and tyrosine residue microenvironment of BSA. Ester catechins had more binding affinity than non-ester catechins. Hydrogen bonds were the main interaction forces of TPs-BSA.


Assuntos
Polifenóis/química , Polifenóis/metabolismo , Soroalbumina Bovina/química , Chá/química , Animais , Sítios de Ligação , Catequina/química , Catequina/metabolismo , Precipitação Química , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Tamanho da Partícula , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Chá/metabolismo , Termodinâmica
8.
Food Chem ; 331: 127355, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32593042

RESUMO

Ara h1 is a major allergen from peanut. We investigated the effect of covalent conjugation of Ara h1 and dietary polyphenols on allergenicity and functional properties of Ara h1. Enzyme-linked immunosorbent assay revealed that the covalent conjugation of dietary polyphenols significantly reduced the IgE binding capacity of Ara h1. Covalent binding of dietary polyphenols with Ara h1 reduced histamine release by 40% in basophils. The decreased IgE binding capacity of Ara h1 could be ascribed to changes in protein conformation. The IgE epitope of Ara h1 might be blocked by polyphenols at the binding site. Analysis of pepsin digestion of Ara h1-polyphenol conjugates indicated that the covalent binding increased pepsin digestibility and reduced IgE binding capacity. Furthermore, covalent conjugation of Ara h1 with polyphenols decreased denaturation temperature and increased antioxidant activity. Ara h1 conjugated with polyphenols may be a promising approach for reducing the allergenicity of Ara h1.


Assuntos
Antígenos de Plantas/química , Antígenos de Plantas/imunologia , Catequina/análogos & derivados , Ácido Clorogênico/química , Proteínas de Membrana/química , Proteínas de Membrana/imunologia , Hipersensibilidade a Amendoim/imunologia , Proteínas de Plantas/química , Proteínas de Plantas/imunologia , Antígenos de Plantas/farmacologia , Antioxidantes/química , Arachis/química , Basófilos/efeitos dos fármacos , Basófilos/imunologia , Basófilos/metabolismo , Catequina/química , Catequina/imunologia , Catequina/metabolismo , Epitopos/metabolismo , Histamina/metabolismo , Humanos , Imunoglobulina E/metabolismo , Proteínas de Membrana/farmacologia , Proteínas de Plantas/farmacologia , Conformação Proteica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectroscopia de Infravermelho com Transformada de Fourier
9.
PLoS One ; 15(4): e0224853, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298262

RESUMO

Diets rich in flavonoids have been related with low obesity rates, which could be related with their potential to inhibit pancreatic lipase, the main enzyme of fat assimilation. Some flavonoids can aggregate in aqueous medium suggesting that the inhibition mechanism could occur on both molecular and colloidal levels. This study investigates the interaction of two flavonoid aggregates, quercetin and epigallocatechin gallate (EGCG), with pancreatic lipase under simplified intestinal conditions. The stability and the morphology of these flavonoid aggregates were studied in four different solutions: Control (water), salt, low lipase concentration and high lipase concentration. Particles were found by optical microscopy in almost all the solutions tested, except EGCG-control. The results show that the precipitation rate decreases for quercetin and increases for EGCG in salt solution and that lipase stabilize quercetin aggregates. In addition, both flavonoids were shown to precipitate together with pancreatic lipase resulting in a sequestering of the enzyme.


Assuntos
Antioxidantes/farmacologia , Catequina/análogos & derivados , Mucosa Intestinal/metabolismo , Lipase/metabolismo , Quercetina/farmacologia , Animais , Antioxidantes/metabolismo , Catequina/metabolismo , Catequina/farmacologia , Dimerização , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/enzimologia , Lipase/antagonistas & inibidores , Quercetina/metabolismo , Suínos
10.
J Appl Microbiol ; 129(3): 601-611, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32281733

RESUMO

AIMS: To study the mechanism of the antibacterial action of tea polyphenols such as catechins and theaflavins against Bacillus coagulans, and the interaction of epigallocatechin gallate (EGCg) or theaflavin 3,3'-di-O-gallate (TFDG) with the surface of B. coagulans cells was investigated. METHODS AND RESULTS: The antibacterial activities of EGCg and TFDG against B. coagulans cells were measured by counting of the viable cells after the mixing with each polyphenol. Bactericidal effect of TFDG was shown at the concentration of greater than or equal to 62·5 mg l-1 ; however, at the same concentration, EGCg did not. According to the results of two dimensional (2D)-electrophoresis analysis, TFDG seemed to interact with cytoplasmic membrane proteins. The activity of the glucose transporters of the cells decreased 40% following the treatment with TFDG of 62·5 mg l-1 ; however, this decrease was only slight in case of EGCg. This result was in accordance with the strength of their bactericidal activities. CONCLUSION: Our results suggest that the direct interaction between membrane proteins and TFDG is an important factor in the antibacterial activity of polymerized catechins, affecting their functions and leading to cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: Tea polyphenols can effectively use the prevention of product spoilage in the food and beverage industry.


Assuntos
Antibacterianos/farmacologia , Bacillus coagulans/efeitos dos fármacos , Biflavonoides/farmacologia , Catequina/análogos & derivados , Bacillus coagulans/metabolismo , Biflavonoides/metabolismo , Catequina/metabolismo , Catequina/farmacologia , Membrana Celular/efeitos dos fármacos , Glucose/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Polifenóis/química , Polifenóis/farmacologia , Chá/química
11.
BMC Plant Biol ; 20(1): 129, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32220242

RESUMO

BACKGROUND: Pear is one of the most important fruit crops worldwide. Anthocyanins and procyanidins (PAs) are important secondary metabolites that affect the appearance and nutritive quality of pear. However, few studies have focused on the molecular mechanism underlying anthocyanin and PA accumulation in pear. RESULTS: We conducted metabolome and transcriptome analyses to identify candidate genes involved in anthocyanin and PA accumulation in young fruits of the pear cultivar 'Clapp Favorite' (CF) and its red mutation cultivar 'Red Clapp Favorite' (RCF). Gene-metabolite correlation analyses revealed a 'core set' of 20 genes that were strongly correlated with 10 anthocyanin and seven PA metabolites. Of these, PcGSTF12 was confirmed to be involved in anthocyanin and PA accumulation by complementation of the tt19-7 Arabidopsis mutant. Interestingly, PcGSTF12 was found to be responsible for the accumulation of procyanidin A3, but not petunidin 3, 5-diglucoside, opposite to the function of AtGSTs in Arabidopsis. Transformation with PcGSTF12 greatly promoted or repressed genes involved in anthocyanin and PA biosynthesis, regulation, and transport. Electrophoretic mobility shift and luciferase reporter assays confirmed positive regulation of PcGSTF12 by PcMYB114. CONCLUSION: These findings identify a core set of genes for anthocyanin and PA accumulation in pear. Of these, PcGSTF12, was confirmed to be involved in anthocyanin and PA accumulation. Our results also identified an important anthocyanin and PA regulation node comprising two core genes, PcGSTF12 and PcMYB114. These results provide novel insights into anthocyanin and PA accumulation in pear and represent a valuable data set to guide future functional studies and pear breeding.


Assuntos
Antocianinas/metabolismo , Biflavonoides/metabolismo , Catequina/metabolismo , Metaboloma , Proantocianidinas/metabolismo , Pyrus/genética , Transcriptoma , Frutas/metabolismo , Pyrus/metabolismo
12.
Carbohydr Polym ; 236: 116044, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32172858

RESUMO

In this study, water and chelator-soluble pectic polysaccharide fractions were obtained from white grape skins, aiming to study their impact on the interaction between low polymerized grape seed procyanidins and salivary proteins. Water and chelator-soluble polysaccharide fractions were composed by uronic acids and neutral sugars, mainly arabinose and galactose, with water polysaccharide fraction showing a higher amount of branched pectic polysaccharides. Both polysaccharide fractions were able to mitigate salivary protein-procyanidin interactions, by a competition mechanism, resulting in a decrease of the amount of precipitated protein. Water polysaccharide fraction was the most effective in inhibiting salivary protein precipitation, especially for acidic proline-rich proteins, due to the higher affinity to interact with procyanidins (KA = 22222 M-1 and KA = 365 M-1 for water and chelator polysaccharides, respectively). The interaction between polysaccharides and procyanidins showed to be mainly governed by hydrophobic effect.


Assuntos
Biflavonoides/metabolismo , Catequina/metabolismo , Pectinas/química , Proantocianidinas/metabolismo , Proteínas e Peptídeos Salivares/metabolismo , Vitis/química , Biflavonoides/análise , Biflavonoides/isolamento & purificação , Catequina/análise , Catequina/isolamento & purificação , Frutas/química , Humanos , Pectinas/análise , Pectinas/isolamento & purificação , Proantocianidinas/análise , Proantocianidinas/isolamento & purificação , Ligação Proteica/efeitos dos fármacos
13.
Biochemistry ; 59(10): 1093-1103, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32100530

RESUMO

Epigallocatechin-3-gallate (EGCG) is a catechin found in green tea that can inhibit the amyloid formation of a wide variety of proteins. EGCG's ability to prevent or redirect the amyloid formation of so many proteins may reflect a common mechanism of action, and thus, greater molecular-level insight into how it exerts its effect could have broad implications. Here, we investigate the molecular details of EGCG's inhibition of the protein ß-2-microglobulin (ß2m), which forms amyloids in patients undergoing long-term dialysis treatment. Using size-exclusion chromatography and a collection of mass spectrometry-based techniques, we find that EGCG prevents Cu(II)-induced ß2m amyloid formation by diverting the normal progression of preamyloid oligomers toward the formation of spherical, redissolvable aggregates. EGCG exerts its effect by binding with a micromolar affinity (Kd ≈ 5 µM) to the ß2m monomer on the edge of two ß-sheets near the N-terminus. This interaction destabilizes the preamyloid dimer and prevents the formation of a tetramer species previously shown to be essential for Cu(II)-induced ß2m amyloid formation. EGCG's binding at the edge of the ß-sheets in ß2m is consistent with a previous hypothesis that EGCG generally prevents amyloid formation by binding cross-ß-sheet aggregation intermediates.


Assuntos
Amiloide/química , Catequina/análogos & derivados , Microglobulina beta-2/química , Amiloide/metabolismo , Proteínas Amiloidogênicas/química , Amiloidose/metabolismo , Catequina/metabolismo , Catequina/farmacologia , Catequina/fisiologia , Cromatografia em Gel/métodos , Cobre/metabolismo , Humanos , Espectrometria de Massas/métodos , Modelos Moleculares , Conformação Proteica em Folha beta/fisiologia , Multimerização Proteica/efeitos dos fármacos , Microglobulina beta-2/antagonistas & inibidores , Microglobulina beta-2/metabolismo
14.
Ecotoxicol Environ Saf ; 192: 110315, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32058162

RESUMO

Tea (Camellia sinensis), widely planted in the south of China, and often exposed to acid rain. However, research concerning the impacts of acid rain on physiology and biochemistry of tea plants is still scarce. In this study, we investigated the influence of simulated acid rain (SAR) on plant height, root length, photosynthetic pigment, Fv/Fm, proline, malondialdehyde, antioxidant enzyme activity, total nitrogen, caffeine, catechins, and free amino acids. Our results showed that SAR at pH 4.5 did not hinder plant development because growth characteristics, photosynthesis, and ascorbate peroxidase and catalase activities did not decrease at this pH compared to those at the other investigated pH values. However, at pH 3.5 and pH 2.5, the activities of antioxidase and concentrations of malondialdehyde and proline increased significantly in response to the decrease of photosynthetic pigments and Fv/Fm. In addition, the increase in acidity increased total nitrogen, certain amino acid content (theanine, cysteine), and decreased catechin and caffeine contents, resulting in an imbalance of the carbon and nitrogen metabolisms. Our results indicated that SAR at pH 3.5 and pH 2.5 could restrict photosynthesis and the antioxidant defense system, causing metabolic disorders and ultimately affecting plant development and growth, but SAR at pH 4.5 had no toxic effects on tea seedlings when no other stress factors are involved.


Assuntos
Chuva Ácida/toxicidade , Camellia sinensis/efeitos dos fármacos , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Cafeína/análise , Camellia sinensis/química , Camellia sinensis/crescimento & desenvolvimento , Camellia sinensis/metabolismo , Catalase/metabolismo , Catequina/metabolismo , Malondialdeído/metabolismo , Nitrogênio/análise , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Folhas de Planta/metabolismo , Plântula/química , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
15.
Ann Palliat Med ; 9(2): 331-338, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32008337

RESUMO

BACKGROUND: This study investigates the effect of epigallocatechin gallate (EGCG) from tea leaves on hyperuricemia and explores the underlying mechanisms in vitro and in vivo. METHODS: The effects of EGCG on proliferation of BRL 3A rat liver cells were evaluated by CCK8 and after stimulation by xanthine the uric acid and xanthine oxidase (XOD) levels were evaluated by a kit; In an in vivo experiment, rats were treated with oxonic acid potassium salt combined with ethylamine pyrimidine to induce high uric acid hematic disease (7 days), The serum uric acid levels and XOD levels were evaluated by a kit, The expressions of OTA1 and GLUT9 were detected by RT-qPCR and Immunohistochemical. RESULTS: EGCG had no effect on proliferation, and significantly reduced serum uric acid levels and inhibited XOD activity (P<0.05). The rat model exhibited a significant rise in blood uric acid levels (54.59 mg/dL), and EGCG significantly reduced the high level of serum uric acid and inhibited XOD activity in the serum and liver tissues (P<0.05). RT-PCR showed that EGCG significantly increased mOAT1 expression in the kidney tissues and reduced mGLUT9 expression (P<0.05). Immunohistochemical results showed that EGCG significantly increased OAT1 expression in the kidney tissues and decreased GLUT9 expression (P<0.05). CONCLUSIONS: These results demonstrate that EGCG has obvious anti-hyperuricemia effects in vitro and in vivo via the inhibition of XOD activity and GLUT9 expression and the promotion of OAT1 expression.


Assuntos
Antioxidantes/farmacologia , Catequina/análogos & derivados , Polifenóis/farmacologia , Ácido Úrico/metabolismo , Xantina Oxidase/metabolismo , Animais , Catequina/metabolismo , Fígado/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Ratos , Ratos Sprague-Dawley , Chá , Ácido Úrico/sangue
16.
Molecules ; 25(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906397

RESUMO

Chinese bayberry leaf proanthocyanidins (BLPs) are Epigallocatechin gallate (EGCG) oligomers or polymers, which have a lot of health-promoting activity. The activity is closely related to their behavior during in vitro digestion, which remains unknown and hinders further investigations. To clarify the changes of BLPs during gastrointestinal digestion, further research is required. For in vitro digestion, including gastric-intestinal digestion, colon fermentation was applied. Caco-2 monolayer transportation was also applied to investigate the behavior of different BLPs with different degrees of polymerization. The trimers and the tetramers were significantly decreased during in vitro gastric-intestinal digestion resulting in a significant increase in the content of dimers. The dimers and trimers were the main compounds utilized by gut microbiota and they were assumed not to degrade through cleavage of the inflavan bond. The monomers and dimers were able to transport through the Caco-2 monolayer at a rate of 10.45% and 6.4%, respectively.


Assuntos
Biopolímeros/metabolismo , Ácido Gálico/análise , Myrica/química , Proantocianidinas/metabolismo , Disponibilidade Biológica , Biopolímeros/análise , Biopolímeros/química , Células CACO-2 , Catequina/análogos & derivados , Catequina/análise , Catequina/química , Catequina/metabolismo , Digestão , Fermentação , Ácido Gálico/química , Ácido Gálico/metabolismo , Mucosa Gástrica/enzimologia , Microbioma Gastrointestinal , Humanos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Intestinos/enzimologia , Folhas de Planta/química , Polimerização , Proantocianidinas/análise , Proantocianidinas/química , Saliva/enzimologia
17.
Molecules ; 25(3)2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31979082

RESUMO

Epigallocatechin gallate (EGCG) is the main bioactive component of catechins predominantly present in svarious types of teas. EGCG is well known for a wide spectrum of biological activity as an anti-oxidative, anti-inflammatory, and anti-tumor agent. The effect of EGCG on cell death mechanisms via the induction of apoptosis, necrosis, and autophagy has been documented. Moreover, its anti-proliferative and chemopreventive action has been demonstrated in many cancer cell lines. It was also involved in the modulation of cyclooxygenase-2, in oxidative stress and inflammation of different cell processes. EGCG has been reported as a promising target for plasma membrane proteins, such as epidermal growth factor receptor (EGFR). In addition, it has been demonstrated a mechanism of action relying on the inhibition of ERK1/2, p38 MAPK, NF-κB, and vascular endothelial growth factor (VEGF). EGCG and its derivatives were used in proteasome inhibition and they were involved in epigenetic mechanisms. In summary, EGCG is the most predominant and bioactive constituent of teas and it has a pivotal role in cancer prevention. Its preclinical pharmacological activities are associated with complex molecular mechanisms that involve numerous signaling pathways.


Assuntos
Catequina/análogos & derivados , Animais , Catequina/metabolismo , Linhagem Celular Tumoral , Receptores ErbB/metabolismo , Humanos , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia , Chá/química , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
18.
Analyst ; 145(2): 588-595, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31776529

RESUMO

Epigallocatechin-gallate (EGCG) is the main polyphenol ingredient of green tea. This compound is a strong antioxidant and oxidizes easily. Numerous studies demonstrated its beneficial effects on the human health, for example its anticancer and anti-inflammatory activity. In the body, EGCG is transported by serum albumin. EGCG easily oxidizes and the interactions of the oxidized form presumably present significant differences. However, the presence of oxidized EGCG is usually neglected in the literature and its effects have not been investigated in detail. Here, we applied the label-free grating coupled interferometry method that performs dual-channel measurements. The measured kinetic signal can be compensated with a signal of a reference channel at each measurement time. By testing both hydrophilic and hydrophobic platforms, we found that EGCG can bind to a wide range of surfaces. Exploiting the dual-channel referencing ability as well as the unique sensitivity and throughput of the employed label-free technique, the experiments revealed the specific interactions between bovine serum albumin (BSA) and EGCG and determined the characteristic dissociation constant (Kd) of the binding equilibrium. The obtained binding constants were compared to literature values, showing reasonable agreement with NMR data. Besides the native EGCG, the oxidized form of EGCG was also examined, whose binding behaviors to serum albumins have never been studied. Overstoichiometric binding obtained; BSA has stronger and weaker binding sites, which could be characterized by two separate Kd values. Furthermore, EGCG oxidization increased the bound amount.


Assuntos
Técnicas Biossensoriais/métodos , Catequina/análogos & derivados , Interferometria/métodos , Soroalbumina Bovina/metabolismo , Albumina Sérica/metabolismo , Animais , Sítios de Ligação , Catequina/química , Catequina/metabolismo , Bovinos , Humanos , Interferometria/instrumentação , Cinética , Oxirredução , Ligação Proteica , Albumina Sérica/química , Soroalbumina Bovina/química
19.
Food Funct ; 11(1): 534-543, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31845690

RESUMO

It has been shown that supplementation of layers' diets with epigallocatechin-3-gallate (EGCG) can improve egg albumen quality, but the underlying mechanisms behind this response are unclear. In this study, we investigate the effect of EGCG on egg antioxidative activity, free amino acid and fatty acid profiles, and the underlying relationship between the EGCG and oxidant-sensitive mitogen-activated protein kinase (MAPK) signaling pathway in laying hens. 288 hens (35-weeks-old) were fed 0 and 165 mg kg-1 of EGCG diets over 8 weeks. EGCG led to an increase in the albumen height, Haugh unit, and activity of glutathione S-transferase (GST) and a reduction in MDA content in plasma (P < 0.05). Egg white tryptophan and yolk carotenoid content was also increased by EGCG (P < 0.05). Eggs from EGCG fed layers had higher total antioxidant capacity (T-AOC), reducing power (RP), and oxygen radical absorbance capacity (ORAC), and lower albumen and yolk MDA content (P < 0.05). Also, liver gene and protein expression of P-38MAPK, nuclear factor erythroid 2-related 2 (Nrf2) and hemeoxygenase 1 (HO-1) was up-regulated by EGCG. Our findings suggest that dietary EGCG increased the antioxidant activity of eggs and regulated the MAPK/Nrf2 signaling pathway.


Assuntos
Antioxidantes/análise , Catequina/análogos & derivados , Galinhas/metabolismo , Ovos/análise , Polifenóis/metabolismo , Ração Animal/análise , Animais , Antioxidantes/metabolismo , Catequina/metabolismo , Galinhas/genética , Suplementos Nutricionais/análise , Feminino , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo
20.
Prep Biochem Biotechnol ; 50(2): 123-132, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31702433

RESUMO

The chemo-profiling of ethanolic extract of faba beans seeds was performed and explored as an α-glucosidase inhibitor. The inhibition of α-glucosidase is one of the alternatives approach to control postprandial hyperglycemia by, resulting in the delay of the carbohydrate digestion of absorbable monosaccharides. Ethanolic seed extract showed phenolic compounds, flavonoid such as gallic acid (m/z [M- H] = 169.0124,C7H6O5) ellagic acid derivatives epigallocatechin (m/z [M- H = 305.0644,C15H14O7),catechin (m/z [M- H] = 289.0656,C15H14O6), epigallocatechin gallate (m/z [M- H] = 457.0578,C22H18O11) and epicatechin monogallate (m/z [M- H] = 441.081, C22H18O10). The extract was found to exert inhibitory activity (88.28 ± 2.67%) (IC50 value of 2.30 ± 0.032 mg/mL) with a mixed mode of inhibition (Km, apparent = 0.54 ± 0.020 mM and Vmax, apparent 0.136 ± 0.04 mM/min). Molecular docking studies of gallic acid and catechin on α-glucosidase proposed productive binding modes having binding energy (-6.58 kcal/mol and -7.25 kcal/mol) with an effective number of hydrogen bonds and binding energy. Tyr63, Arg197, Asp198, Glu 233, Asn324, Asp 326 of α-glucosidase participated in binding events with gallic acid and catechin. Molecular dynamics simulation studies were performed for both complexes i.e. gal:α-glucosidase and cat:α-glucosidase along with apo state of α-glucosidase, which revealed stable systems during the simulation. These findings of the present study may give an insight into the further development of the novel antidiabetic drug from the seeds of faba beans.


Assuntos
Catequina/metabolismo , Ácido Gálico/metabolismo , Extratos Vegetais/farmacologia , Polifenóis/metabolismo , Vicia faba/metabolismo , alfa-Glucosidases/metabolismo , Cromatografia Líquida de Alta Pressão , Inibidores de Glicosídeo Hidrolases/farmacologia , Simulação de Acoplamento Molecular , Sementes/química , Espectrometria de Massas por Ionização por Electrospray , Vicia faba/embriologia
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