Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.260
Filtrar
1.
Chem Pharm Bull (Tokyo) ; 68(2): 140-149, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32009081

RESUMO

Previously, we reported that the c-Met inhibitory effect of Ephedra Herb extract (EHE) is derived from ingredients besides ephedrine alkaloids. Moreover, analgesic and anti-influenza activities of EHE and ephedrine alkaloids-free Ephedra Herb extract (EFE) have been reported recently. In this study, we examined the fractions containing c-Met kinase inhibitory activity from EHE and the fractions with analgesic and anti-influenza activities from EFE, and elucidated the structural characteristics of the active fractions. Significant c-Met kinase activity was observed in 30, 40, and 50% methanol (MeOH) eluate fractions obtained from water extract of EHE using Diaion HP-20 column chromatography. Similarly, 20 and 40% MeOH, and MeOH eluate fractions obtained from water extract of EFE were found to display analgesic and anti-influenza activities. Reversed phase-HPLC analysis of the active fractions commonly showed broad peaks characteristic of high-molecular mass condensed tannin. The active fractions were analyzed using 13C-NMR and decomposition reactions; the deduced structures of active components were high-molecular mass condensed tannins, which were mainly procyanidin B-type and partly procyanidin A-type, including pyrogallol- and catechol-type flavan 3-ols as extension and terminal units. HPLC and gel permeation chromatography (GPC) analyses estimated that the ratio of pyrogallol- and catechol-type was approximately 9 : 2, and the weight-average molecular weight based on the polystyrene standard was >45000. Furthermore, GPC-based analysis was proposed as the quality evaluation method for high-molecular mass condensed tannin in EHE and EFE.


Assuntos
Ephedra/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Alcaloides/química , Alcaloides/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Antivirais/química , Antivirais/farmacologia , Biflavonoides/química , Biflavonoides/farmacologia , Catequina/química , Catequina/farmacologia , Linhagem Celular Tumoral , Cães , Efedrina/química , Efedrina/farmacologia , Humanos , Células Madin Darby de Rim Canino , Masculino , Camundongos , Proantocianidinas/química , Proantocianidinas/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores
2.
J Agric Food Chem ; 68(10): 3033-3049, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32052629

RESUMO

The high levels of secondary metabolites in rapeseed play important roles in determining the oil quality and feeding value. Here, we characterized the metabolic profiles in seeds of various yellow- and black-seeded rapeseed accessions. Two hundred and forty-eight features were characterized, including 31 phenolic acids, 54 flavonoids, 24 glucosinolates, 65 lipid compounds, and 74 other polar compounds. The most abundant phenolic acids and various flavonoids (epicatechin, isorhamnetin, kaempferol, quercetin, and their derivatives) were widely detected and showed significant differences in distribution between the yellow- and black-seeded rapeseed. Furthermore, the related genes (e.g., BnTT3, BnTT18, BnTT10, BnTT12, and BnBAN) involved in the proanthocyanidin pathway had lower expression levels in yellow-seeded rapeseed, strongly suggesting that the seed coat color could be mainly determined by the levels of epicatechin and their derivatives. These results improve our understanding of the primary constituents of rapeseed and lay the foundation for breeding novel varieties with a high nutritional value.


Assuntos
Brassica napus/química , Extratos Vegetais/química , Brassica napus/classificação , Brassica napus/genética , Brassica napus/metabolismo , Catequina/química , Cromatografia Líquida de Alta Pressão , Cor , Flavonoides/química , Hidroxibenzoatos/química , Metaboloma , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/química , Espectrometria de Massas em Tandem
3.
J Agric Food Chem ; 68(10): 3238-3249, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32059106

RESUMO

Enrichment of multiple bioactive components with different characters into one food substrate simultaneously is a challenge. In this study, the hydrophilic epigallocatechin gallate (EGCG) and the hydrophobic quercetin were simultaneously enriched in the cavity of phytoferritin from red bean seed deprived of iron (apoRBF), a cagelike protein. The interactions of apoRBF with EGCG and quercetin were evaluated by UV/visible absorption, fluorescence, and circular dichroism technologies. By combination of the reversible assembly and urea induced approaches, both EGCG and quercetin were successfully coencapsulated in apoRBF to fabricate four kinds of apoRBF-EGCG-quercetin nanocomplexes FEQ (FEQ1, FEQ2, FEQ3, and FEQ4) with good solubility in aqueous solution. All FEQ samples maintained the typically spherical morphology of ferritin cage with a diameter around 12 nm. Among the four FEQ samples, the FEQ1 prepared by involving a pH 2.0/6.7 transition scheme was more effective in encapsulating EGCG and quercetin molecules than that by the urea induced method. Furthermore, all FEQs facilitated the stability of EGCG and quercetin molecules relative to free ones, and simultaneous coencapsulation of EGCG and quercetin could significantly improve the quercetin stability as compared with that of the free one and quercetin-loaded ferritin (p < 0.05), respectively. This work provides a new scheme to design and fabricate the ferritin based carrier for encapsulation of multiple bioactive components, and it is beneficial for the intensification of multifunction in one food substrate.


Assuntos
Catequina/análogos & derivados , Ferritinas/química , Proteínas de Plantas/química , Catequina/química , Portadores de Fármacos/química , Composição de Medicamentos , Estabilidade de Medicamentos , Fabaceae/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Sementes/química
4.
J Agric Food Chem ; 68(10): 3163-3170, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32069043

RESUMO

The purpose of this work was to develop a facile strategy based on self-crosslinking between the core and wall materials in the coacervation system for effective procyanidins (PCs) encapsulation. The coacervates were constructed through the interaction of bioactive PCs, gelatin, and sodium alginate, followed by forming cationic bridge of sodium alginate-calcium ions to improve the stability of PCs. When the concentration of PCs and calcium ions were 6.25 and 0.24 mg/mL, respectively, the PC-loaded coacervates showed spherical shape with a size about 150 nm, and the microcapsulation efficiency and yield was 81.19 ± 1.47 and 87.86 ± 2.67%, respectively. The photothermal stability of PCs was effectively improved by embedding them in coacervates. The decrease of mitochondrial membrane potential in PC-12 cells induced by H2O2 was significantly inhibited by PC coacervates, demonstrating an improved protection effect of PCs after being encapsulated in coacervates.


Assuntos
Biflavonoides/química , Quelantes de Cálcio/química , Cálcio/química , Catequina/química , Extratos Vegetais/química , Proantocianidinas/química , Animais , Reagentes para Ligações Cruzadas/química , Estabilidade de Medicamentos , Íons/química , Células PC12 , Ratos , Sementes/química , Vitis
5.
J Photochem Photobiol B ; 203: 111774, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31931386

RESUMO

Zeolitic imidazole framework (ZIF) is an emerging class of metal organic frameworks exhibiting unique features such as crystalline nature with tunable pore size, large surface area and biocompatible nature. Exceptional thermal and chemical stabilities of ZIF-L make it a suitable candidate for biomedical applications. The present study has focused on the single step fabrication of catechin encapsulated ZIF-L and evaluation of its antibiofilm efficiency, larvicidal activity and dye degradation ability. The as- prepared CA@ZIF-L nanocomposite was characterized by spectroscopic and microscopic techniques. The results revealed that the CA@ZIF-L showed significant toxicity against mosquito larvae in a dose dependent manner with the IC50 63.43±1.25 µg/mL. CA@ZIF-L showed dose dependent reduction of biofilm formation in both ATCC and clinical MRSA strains. In addition, CA@ZIF-L exhibited excellent photocatalytic activity with around 92% degradation of methylene blue under direct sunlight. Overall, the present work highlights the possibility of employing the multifunctional CA@ZIF-L nanocomposite as a suitable material for biomedical and photocatalytic applications.


Assuntos
Biofilmes/efeitos dos fármacos , Catequina/química , Estruturas Metalorgânicas/química , Nanocompostos/toxicidade , Zeolitas/química , Animais , Catálise , Culicidae/efeitos dos fármacos , Culicidae/crescimento & desenvolvimento , Imidazóis/química , Larva/efeitos dos fármacos , Luz , Staphylococcus aureus Resistente à Meticilina/fisiologia , Azul de Metileno/química , Nanocompostos/química , Tamanho da Partícula , Fotólise/efeitos da radiação
6.
Phys Chem Chem Phys ; 22(4): 2212-2228, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31913367

RESUMO

In this work, the interaction of a bioactive tea polyphenol (-)-epigallocatechin gallate (EGCG) with bovine hemoglobin (BHb) along with its anti-oxidative behavior and the anti-glycation property have been explored using multi-spectroscopic and computational techniques. The binding affinity for EGCG towards BHb was observed to be moderate in nature with an order of 104 M-1, and the fluorescence quenching mechanism was characterized by an unusual static quenching mechanism. The binding constant (Kb) showed a continuous enhancement with temperature from 3.468 ± 0.380 × 104 M-1 at 288 K to 6.017 ± 0.601 × 104 M-1 at 310 K. The fluorescence emission measurements along with molecular docking studies indicated that EGCG binds near the most dominant fluorophore of BHb (ß2-Trp37, at the interface of α1 and ß2 chains) within the pocket formed by the α1, α2 and ß2 chains. The sign and magnitude of the thermodynamic parameters, changes in enthalpy (ΔH = +17.004 ± 1.007 kJ mol-1) and in entropy (ΔS = +146.213 ± 2.390 J K-1 mol-1), indicate that hydrophobic forces play a major role in stabilizing the BHb-EGCG complex. The micro-environment around the EGCG binding site showed an increase in hydrophobicity upon ligand binding. The binding of EGCG with BHb leads to a decrease in the α-helical content, whereas that of the ß-sheet increased. FTIR studies also indicated that the secondary structure of BHb changed upon binding with EGCG, along with providing further support for the presence of hydrophobic forces in the complexation process. Molecular docking studies indicated that EGCG binds within the cavity of α1, α2, and ß2 chains surrounded by residues such as α1- Lys99, α1-Thr134, α1-Thr137, α1-Tyr140, α2-Lys127 and ß2-Trp37. Molecular dynamics simulation studies indicated that EGCG conferred additional stability to BHb. Furthermore, moving away from the binding studies, EGCG was found to prevent the glyoxal (GO)-mediated glycation process of BHb, and it was also found to act as a potent antioxidant against the photo-oxidative damage of BHb.


Assuntos
Catequina/análogos & derivados , Hemoglobinas/química , Hemoglobinas/metabolismo , Polifenóis/metabolismo , Animais , Catequina/química , Bovinos , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Polifenóis/química , Ligação Proteica , Análise Espectral
7.
J Agric Food Chem ; 68(7): 2016-2023, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986021

RESUMO

The protein precipitation (PP) of bovine serum albumin (BSA), lysozyme (LYS), and alfalfa leaf protein (ALF) by four procyanidin-rich condensed tannin (CT) samples in both 2-[N-morpholino]ethanesulfonic acid (MES) and a modified Goering-Van Soest (GVS) buffer is described. Purified CT samples examined included Vitis vinifera seed (mean degree of polymerization [mDP] 4.1, 16.5% galloylated), Tilia sp. flowers (B-type linkages, mDP 5.9), Vaccinium macrocarpon berries (mDP 8.7, 31.7% A-type linkages). and Trifolium pratense flowers (B-type linkages, mDP 12.3) and were characterized by 2D NMR (>90% purity). In general, CTs precipitated ALF > LYS ≥ BSA. PP in GVS buffer was 1 to 2.25 times greater than that in MES buffer (25 °C). The GVS buffer system better reflects the results/conclusions from the literature on the impacts mDP, galloylation, and A-type linkages have on PP. Determinations of PP using the MES buffer at 37 °C indicated that some of these differences may be attributed to the temperature at which GVS buffer determinations are conducted. In vitro PP studies using the GVS buffer may offer better guidance when selecting CT-containing forages and amendments for ruminant feeding studies.


Assuntos
Biflavonoides/química , Catequina/química , Extratos Vegetais/química , Proteínas de Plantas/química , Proantocianidinas/química , Soroalbumina Bovina/química , Ração Animal/análise , Tampões (Química) , Precipitação Química , Medicago sativa/química , Muramidase/química , Tilia/química , Vaccinium macrocarpon/química , Vitis/química
8.
J Agric Food Chem ; 68(6): 1714-1724, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31957424

RESUMO

(-)-Epigallocatechin gallate (EGCG) had a significant effect on Maillard reaction intermediate formation in the xylose/alanine model system. A trapping effect of EGCG on the reactive deoxyosones was observed to change the reaction pathways. The rate constant of Amadori rearrangement product (ARP) conversion to deoxyosones was decreased with EGCG addition, indicating an inhibition of ARP degradation. Dehydration improved the ARP formation during the thermal reaction and synergistically improved the yield of ARP with the EGCG trapping effect on the deoxyosones. Additionally, EGCG decreased the activation energy for the conversion of xylose/alanine to ARP (from 77.8 to 62.8 kJ/mol) and in turn accelerated the ARP formation. The effect of EGCG was further facilitated at the optimal conditions of 90 °C, at pH 7.5, and a molar ratio of xylose to alanine of 2:1, which improved the yield of ARP (N-(1-deoxy-d-xylulos-1-yl)alanine) from 2 to 95%.


Assuntos
Alanina/análogos & derivados , Catequina/análogos & derivados , Catequina/química , Produtos Finais de Glicação Avançada/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Reação de Maillard , Xilose/química , Xilulose/química
9.
J Photochem Photobiol B ; 202: 111704, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31743829

RESUMO

Ultraviolet B (UVB) induces inflammation and causes skin aging. The signs of skin aging, such as wrinkles, discolored spots, loss of skin moisture, and disruption of the skin barrier, are mostly caused by inflammatory signaling among various skin layers. The cells on the outermost surface of the skin are keratinocytes; these cells protect the skin against environmental stress and play an important role in immunomodulation by secreting cytokines in response to environmental stress. In the present study, we found that UVB activates STAT1 to mediate inflammatory signaling, yet STAT1 (S272) and STAT (Y702) shows different responses against UVB exposure. Anhua drak tea is a post-fermented dark tea produced in Anhua and Xinhua country in Hunan province of China. Treatment with 2S,3R-6-methoxycarbonylgallocatechin (MCGE), an epigallocatechin gallate derivative isolated from black tea (Anhua dark tea), effectively suppresses STAT1 activation and inflammatory cytokines, and activates Nrf2 pathway to protect cells from reactive oxygen species production in UVB exposed keratinocyte cells (HaCaT). Interestingly, the effects of MCGE were independent on MAPK signaling pathway. Moreover, MCGE regulates inflammatory cytokines in monocyte-keratinocyte (THP-1, HaCaT) co-culture and macrophage differentiation models. These results suggest that MCGE potentially can be used as a photoprotective agent against UVB-induced inflammatory responses.


Assuntos
Catequina/farmacologia , Protetores contra Radiação/farmacologia , Transdução de Sinais/efeitos dos fármacos , Chá/química , Raios Ultravioleta , Sítios de Ligação , Catequina/análogos & derivados , Catequina/química , Catequina/isolamento & purificação , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/efeitos da radiação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Técnicas de Cocultura , Citocinas/metabolismo , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/efeitos da radiação , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Estrutura Terciária de Proteína , Protetores contra Radiação/química , Protetores contra Radiação/isolamento & purificação , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição STAT1/química , Fator de Transcrição STAT1/metabolismo , Transdução de Sinais/efeitos da radiação , Chá/metabolismo
10.
Cell Prolif ; 53(1): e12730, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31746040

RESUMO

OBJECTIVES: In peripheral neuropathy, the underlying mechanisms of nerve and muscle degeneration include chronic inflammation and oxidative stress in fibrotic tissues. (-)-Epigallocatechin gallate (EGCG) is a major, active component in green tea and may scavenge free radical oxygen and attenuate inflammation. Conservative treatments such as steroid injection only deal with early, asymptomatic, peripheral neuropathy. In contrast, neurolysis and nerve conduit implantation work effectively for treating advanced stages. MATERIALS AND METHODS: An EGCG-loaded polycaprolactone (PCL) porous scaffold was fabricated using an integrated moulding method. We evaluated proliferative, oxidative and inflammatory activity of rat Schwann cells (RSCs) and rat skeletal muscle cells (RSMCs) cultured on different scaffolds in vitro. In a rat radiation injury model, we assessed the morphological, electrophysiological and functional performance of regenerated sciatic nerves and gastrocnemius muscles, as well as oxidative stress and inflammation state. RESULTS: RSCs and RSMCs exhibited higher proliferative, anti-oxidant and anti-inflammatory states in an EGCG/PCL scaffold. In vivo studies showed improved nerve and muscle recovery in the EGCG/PCL group, with increased nerve myelination and muscle fibre proliferation and reduced macrophage infiltration, lipid peroxidation, inflammation and oxidative stress indicators. CONCLUSIONS: The EGCG-modified PCL porous nerve scaffold alleviates cellular oxidative stress and repairs peripheral nerve and muscle structure in rats. It attenuates oxidative stress and inflammation in vivo and may provide further insights into peripheral nerve repair in the future.


Assuntos
Catequina/análogos & derivados , Regeneração Nervosa/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Estresse Oxidativo , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Poliésteres , Lesões Experimentais por Radiação/tratamento farmacológico , Células de Schwann/metabolismo , Nervo Isquiático/fisiologia , Tecidos Suporte/química , Animais , Catequina/química , Catequina/farmacologia , Linhagem Celular , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Doenças do Sistema Nervoso Periférico/metabolismo , Doenças do Sistema Nervoso Periférico/patologia , Poliésteres/química , Poliésteres/farmacologia , Porosidade , Lesões Experimentais por Radiação/metabolismo , Lesões Experimentais por Radiação/patologia , Ratos , Células de Schwann/patologia , Nervo Isquiático/lesões , Nervo Isquiático/patologia
11.
Food Chem ; 309: 125769, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31734007

RESUMO

Phenolic compounds are known to bind non-covalently with starch, but the impact of this interaction on the stability of the phenolic compounds through processing and digestion has received little attention. In this study, we examined the recovery of intact phenolic compounds (gallic acid-GA, catechin-CAT and epigallocatechin gallate-EGCG) from processed and digested porridges with different formulations (starch or starch/protein). We observed that phenolics were less degraded in presence of starch only than in presence of starch + proteins. This protection seemed to be linked to the ability of the phenolic compounds to form V-type inclusion complexes with starch, with GA, CAT and EGCG in decreasing order of protection. This work could influence formulation of functional cereal-based foods containing phenolic compounds in order to maximize their retention.


Assuntos
Manipulação de Alimentos/métodos , Fenóis/química , Proteínas/química , Amido/química , Catequina/análogos & derivados , Catequina/química , Catequina/metabolismo , Ácido Gálico/química , Ácido Gálico/metabolismo , Gelatina/química , Gelatina/metabolismo , Fenóis/metabolismo , Proteínas/metabolismo , Amido/metabolismo
12.
Food Chem ; 303: 125380, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31445175

RESUMO

Soybean Bowman-Birk trypsin inhibitor (BBTI), an antinutritional factor of soy products, could strongly inhibit the protein digestion. The inactivation effect and mechanism of BBTI induced by tea polyphenols (TPs) and its major components (EGCG and EGC), were investigated in this study using fluorescence, FTIR, CD spectroscopy, isothermal titration calorimetry (ITC) and molecular docking. EGCG and EGC interacted with BBTI via static quenching process and hydrophobic interaction, with binding constant (Ka) of 2.19 × 103 M-1 and 0.25 × 103 M-1 at 298 K, respectively. TPs, EGCG and EGC induced a transition of BBTI conformation from disorder to order. ITC analysis and molecular docking revealed the interaction of EGCG-BBTI and EGC-BBTI were spontaneous, and hydrophobic interactions and hydrogen bonds were the predominant forces. Overall, this study clearly suggested that EGCG could be a promising inactivating agent for BBTI, which could also improve the safety and nutritional value of soy products.


Assuntos
Catequina/análogos & derivados , Simulação de Acoplamento Molecular , Inibidor da Tripsina de Soja de Bowman-Birk/química , Catequina/química , Catequina/farmacologia , Fluorescência , Ligações de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Conformação Proteica , Termodinâmica , Inibidor da Tripsina de Soja de Bowman-Birk/efeitos dos fármacos , Inibidor da Tripsina de Soja de Bowman-Birk/metabolismo
13.
Food Chem ; 303: 125407, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466032

RESUMO

Theaflavin (TF), which is the key pigment in black tea, is a health-promoting food component with beneficial effects on humans. However, the interactions by which these effects are transferred and exerted into protein-rich foods are unclear. Here, egg ovalbumin (OVA) was selected as a representative dietary protein to ascertain their binding mechanism. Steady-state, time-resolved fluorescence and isothermal titration calorimetric results showed that TF can interact well with OVA with an affinity magnitude of 104. The noncovalent binding was mainly driven by hydrophobic interaction and hydrogen bonds. Structural analysis displayed that the TF binding pocket significantly overlapped with one of the surrounding specific IgE-binding epitopes, thereby causing a subtle structural adjustment on the secondary conformation of OVA. The biological complexation model that was delineated here will help understand how black tea dyes egg white in tea egg products and for the development of protein-rich carriers in functional foods.


Assuntos
Biflavonoides/química , Camellia sinensis/química , Catequina/química , Clara de Ovo/química , Ovalbumina/química , Pigmentos Biológicos/química , Extratos Vegetais/química , Animais , Galinhas , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Ligação Proteica , Chá/química
14.
Food Chem ; 305: 125454, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505413

RESUMO

The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.


Assuntos
Materiais Biomiméticos/química , Catequina/análogos & derivados , Armazenamento de Alimentos/métodos , Gelatina/química , Alimentos Marinhos/análise , Aeromonas/efeitos dos fármacos , Animais , Aminas Biogênicas/análise , Materiais Biomiméticos/farmacologia , Catequina/química , Peroxidação de Lipídeos/efeitos dos fármacos , Desnaturação Proteica/efeitos dos fármacos , Proteínas/química , Pseudomonas/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Paladar/efeitos dos fármacos , Temperatura Ambiente
15.
Biophys Chem ; 256: 106282, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31756664

RESUMO

Structural investigations, based on density functional theory (DFT) calculations, are performed on tea catechins, including 4-aminobutyric acid (GABA), L-theanine (Thea), caffeine (CAF), theobromine (TB), theophylline (TP), catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (CG), epicatechin gallate (ECG), gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG). With an identified lowest energy conformer of investigated molecules, FTIR and FT-Raman spectra have been assigned according to DFT calculations in the way of B3LYP/6-31 + G (d, p). Normal spectra of these catechin powders are also measured by Raman spectrometers. There is a kind of everlasting correlation between experimental results and theoretical data. And our research has also obtained a clear evidence for reliable assignments of vibrational bands, bringing great feasibility to the rapid tea catechin detection.


Assuntos
Catequina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Chá/química , Catequina/análogos & derivados , Chá/metabolismo
16.
Food Chem ; 309: 125609, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31678671

RESUMO

Epigallocatechin (EGC) was acylated with selected fatty acids, namely propionic acid [C3:0], caprylic acid [C8:0], lauric acid [C12:0], stearic acid [C18:0]) and docosahexaenoic acid (DHA)[C22:6n-3] in order to increase its lipophilicity. Monoesters were identified as the predominant products (~40%) followed by diesters (~33%), triesters (~9%) and trace amounts of tetra- and pentaesters. 1H NMR, 13C NMR and HPLC-DAD-MS were used to elucidate the acylation sites and structures of new EGC esters. According to the HPLC-MS analysis of the caprylate esters, EGC-4'-O-caprylate (27%), EGC-3'-O-caprylate or EGC-5'-O-caprylate (12%) and EGC-3',5'-O-dicaprylate (16%) were the major compounds generated upon the acylation reaction of EGC. The acylation significantly increased the lipophilicity of EGC. In addition, EGC and its esters showed radical scavenging activities against DPPH radical and ABTS radical cation. Therefore, EGC esters could serve as potential sources of antioxidants for application in both hydrophilic and lipophilic media.


Assuntos
Antioxidantes/química , Catequina/análogos & derivados , Ácidos Graxos/química , Antioxidantes/farmacologia , Catequina/química , Cromatografia Líquida de Alta Pressão , Ésteres/química , Depuradores de Radicais Livres/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Relação Estrutura-Atividade
17.
Food Chem ; 309: 125718, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31753688

RESUMO

The present study was aimed to investigate the effects of non-covalent and covalent interactions between soy protein isolate (SPI) and different concentrations (1, 2 and 5 mM) of (-)-epigallocatechin gallate (EGCG) regarding the structural and functional properties of the complex. The combination with EGCG caused changes in the secondary structure of SPI. The covalent complexes formed at low concentrations of EGCG tended to form a network structure. Compared with the SPI-EGCG non-covalent complexes, the covalent complexes exhibited higher thermal stability and oxidation resistance and a polyphenol-protective effect. In addition, the corresponding anti-digestive ability of the covalent complexes was strong and would therefore be more stable in the intestinal tract. The findings of this study provide a theoretical reference and research basis for the use of different SPI-polyphenol complexes as functional food ingredients or as bioactive materials.


Assuntos
Catequina/análogos & derivados , Proteínas de Soja/química , Antioxidantes/química , Catequina/química , Catequina/metabolismo , Oxirredução , Tamanho da Partícula , Polifenóis/análise , Estabilidade Proteica , Estrutura Secundária de Proteína , Proteínas de Soja/metabolismo , Temperatura Ambiente
18.
Talanta ; 207: 120349, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594572

RESUMO

In this work, for the first time, the direct usability of natural products, catechins (CT) and cocoa powder (CO), as electrochemical mediators able to modify a carbon black modified screen-printed electrode (SPE-CB) is proved, and, as proof of applicability, free (GSH) and total glutathione (GSH + GSSG) in blood samples is successfully determined. Noteworthy, the cocoa powder (naturally rich in catechins), dissolved in DMSO, was able to give rise to a useful highly redox-active catechol-quinone surface-confined system onto a carbon black nanoparticles modified screen-printed electrode (SPE-CB-CO - Cocoatrode), giving rise to a similar behaviour obtained with pure catechins (SPE-CB-CT). The electrodeposition process has been carefully studied, the resulting immobilized natural mediator (obtained using both CT and CO) features investigated, and the performance of the resulting sensors (SPE-CB-CT and Cocoatrode) tested and compared. Both modified electrodes (SPE-CB-CT and Cocoatrode) have a good inter-electrodes precision (RSD ip,a ≤ 4.2%, n = 3) and intra-electrodes repeatability (RSD ip,a ≤ 3.9%, n = 20), indicating a robust and stable 'fabrication' strategy. Finally, SPE-CB-CT and Cocoatrode have been employed for the detection of free (GSH) and total (GSH+GSSG) glutathione in blood samples, using differential pulse voltammetry decrease in the mediator's reduction peak (Δi %), as analytical signal. Analytical curves (R2 ≥ 0.998), for the GSH detection, have been determined both with SPE-CB-CT and Cocoatrode in the 2.5 × 10-8-6.0 × 10-5 M and 5.0 × 10-8-1.0 × 10-4 M concentration ranges, respectively. Limits of detections (LODs) were ≤2.6 × 10-8 M. GSH (free and total) determined in blood samples, by the proposed CT and CO sensors, showed a good intra-electrode repeatability (RSD ip,a ≤ 9.0%, n = 3), with good recoveries (from 88.3% to 117.7%). The values obtained were in agreement with a classical spectrophotometric method (GSH and GSSG concentration relative error between -4.7 and +9.8%). The SPE-CB-CT and the Cocoatrode platforms demonstrated high potentiality in sensing and biosensing scenario, opening new gates to the natural/food products employment as unconventional, eco-friendly and economically affordable analytical active tools.


Assuntos
Análise Química do Sangue/instrumentação , Catequina/química , Chocolate , Glutationa/sangue , Impressão , Fuligem/química , Eletroquímica , Eletrodos , Glutationa/química
19.
Food Chem ; 302: 125347, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430631

RESUMO

This work aims to prolong the storage stability of polyphenols, obtained from grape pomace, using a spray drying-based microencapsulation technique. The microcapsules obtained under optimal conditions were stored at two different relative humidities (33% and 52%) during 75 days. The analyses of total phenolic content, antioxidant activity, and individual phenolic compounds were carried out every 15 days, and the most stable microcapsules were achieved with maltodextrin DE4-7 prepared by adding gum Arabic to the wall material at a ratio of 8:2. The phenolic content loss rate was found to be in a range of 0.93-5.42 % depending on phenolic compound. The decrease in the content of rutin, chlorogenic acid, epicatechin, caffeic acid, gallic acid, caftaric acid and catechin was only 0.93, 2.09, 2.13, 2.27, 2.41, 3.40 and 5.42%, respectively. These results indicate more efficient storage conditions than those of previously reported studies.


Assuntos
Cápsulas/química , Armazenamento de Alimentos , Polifenóis/química , Vitis/química , Antioxidantes/análise , Antioxidantes/química , Catequina/análise , Catequina/química , Ácido Clorogênico/análise , Ácido Clorogênico/química , Composição de Medicamentos/métodos , Goma Arábica/química , Umidade , Fenóis/análise , Fenóis/química , Extratos Vegetais/química , Polifenóis/análise , Polissacarídeos/química , Rutina/análise , Rutina/química
20.
Drug Deliv ; 26(1): 1058-1067, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31735064

RESUMO

Realgar and (-)-Epigallocatechin-3-gallate (EGCG) are natural medicines that inhibit cancer cell growth, resulting in inhibition of formation and development of tumors. The anticancer effects of realgar and EGCG were greatly improved following formulation as nanoparticles. EGCG has received increased attention as a drug carrier. The aim of this study was to prepare a new nanomedicine, (EGCG-RNPs), in which encapsulated nano-realgar. EGCG-RNPs were prepared by coprecipitation and characterized by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), particle size and zeta potential, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and in vitro release. Furthermore, we evaluated the antiproliferative effects of EGCG-RNPs on HL-60 cells in vitro, antitumor effect by intratumoral injection of EGCG-RNPs into solid tumors derived from APL HL-60 cells in vivo. Possible mechanisms were evaluated using uptake and efflux experiments in HL-60 cells. The results showed that the average particle size and zeta potentials of EGCG-RNPs was 200.3 ± 1.23 nm and -46.8 ± 1.31 mV. Controlled release of EGCG-RNPs was sustained and continued up to 72 h in vitro. Compared with nano-realgar and EGCG + RNPs (EGCG and nano-realgar physical mixing), EGCG-RNPs significantly inhibited growth of HL-60 cells. In a solid tumor model, EGCG-RNPs decreased tumor volumes, with an inhibitory rate of 60.18% at a dose of 70 mg · kg-1. The mechanisms of antitumor improvement may correlate with the increased uptake of realgar and prolonged the retention time of realgar in HL-60 cells due to EGCG as a carrier. EGCG-RNPs could enhance anticancer therapeutic efficacy for acute promyelocytic leukemia.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Catequina/análogos & derivados , Leucemia Promielocítica Aguda/tratamento farmacológico , Nanopartículas/química , Varredura Diferencial de Calorimetria/métodos , Catequina/química , Catequina/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Células HL-60 , Humanos , Nanomedicina/métodos , Tamanho da Partícula
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA