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1.
Food Chem ; 366: 130521, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34314931

RESUMO

Though the instability of polyphenols in cell culture experiment has been investigated previously, the underlying mechanism is not completely clear yet. Therefore, in this study, the stability of epigallocatechin gallate (EGCG) in cell culture medium DMEM was investigated at 4 °C and 37 °C via UPLC-MS-MS analysis followed by determination of the antioxidant capacity of EGCG. EGCG was instable in DMEM and formed various degradation products derived from its dimer with increasing incubation time with many isomers being formed at both temperatures. The dimer products were more stable at 4 °C than at 37 °C. The structure and formation mechanism of five products were analyzed with four unidentified. Ascorbic acid significantly improved the stability of EGCG by protecting EGCG from auto-oxidation in DMEM, particularly at 4 °C. The antioxidative activity of EGCG in DMEM was determined by DPPH, ABTS and FRAP assay. The antioxidative properties of EGCG continuously decreased over 8 h in DMEM, which was consistent with its course of degradation.


Assuntos
Antioxidantes , Espectrometria de Massas em Tandem , Catequina/análogos & derivados , Cromatografia Líquida , Oxirredução
2.
Food Chem ; 366: 130422, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34392082

RESUMO

Tea cream, produced by interactions among tea ingredients, is undesirable in tea beverage industry. The interaction between bovine serum albumin (BSA) and theaflavin-3,3'-digallate (TFDG, an important component in tea cream and functional substance of black tea) was investigated by fluorescence spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, synchronous fluorescence spectroscopy, fourier-transform infrared (FT-IR) spectroscopy, and molecular docking technique. Multi-spectroscopic experiments demonstrated that TFDG interacted with BSA via static quenching, and the microenvironment around BSA became more hydrophobicity. FT-IR showed that the α-helix of BSA was increased when binding with TFDG. Thermodynamic parameters and molecular docking demonstrated that hydrophobic interactions and hydrogen bonds dominated the interaction between TFDG and BSA. The mechanism proposed in this research could further develop some nanoparticles to excellent biochemical properties while reducing the formation of tea cream, and explore the potential of BSA as transport carrier for TFDG.


Assuntos
Soroalbumina Bovina , Biflavonoides , Sítios de Ligação , Catequina/análogos & derivados , Dicroísmo Circular , Simulação de Acoplamento Molecular , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
3.
Food Chem ; 368: 130865, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34428692

RESUMO

There are few studies on controlling the formation of heterocyclic amines (HAs) by adding polyphenols to roasted lamb. The aim of this study was to assess the inhibitory effect of 0.025, 0.125, and 0.625 mmol of chlorogenic acid, epicatechin, rutin, quercetin and quinic acid on the formation of HAs in charcoal roasted lamb, respectively, by UHPLC-MS/MS. The results indicated that Harman, Norharman, PhIP, IQx and 8-MeIQx were detected, but both chlorogenic acid and epicatechin greatly inhibited the formation of IQx, 8-MeIQx, Norharman, Harman and PhIP, and epicatechin had better inhibitory effect than chlorogenic acid. PLSR-VID analysis suggested the key precursors of HAs formation in roasted lamb were glucose, ribose, fructose, isoleucine, valine, and lysine. In addition, this work also implied that the potential mechanism of inhibition of HAs formation by chlorogenic acid and epicatechin in roasted lamb might attribute to competitive chemical reactions between polyphenols and key precursors of HAs.


Assuntos
Catequina , Compostos Heterocíclicos , Carne Vermelha , Aminas/análise , Animais , Carvão Vegetal , Ácido Clorogênico , Culinária , Compostos Heterocíclicos/análise , Carne/análise , Carne Vermelha/análise , Ovinos , Espectrometria de Massas em Tandem
4.
Food Chem ; 369: 130884, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34455317

RESUMO

This study aimed at investigating the effects of interactions between dietary dicarbonyl scavengers coexisting in human plasma on the overall methylglyoxal scavenging potential. Apart from being the most effective dicarbonyl scavengers, epicatechin or cysteine, which can be easily oxidized by other compounds, was reacted with methylglyoxal in the presence of certain other dicarbonyl scavengers under simulated physiological conditions (pH 7.4, 37 °C). Methylglyoxal was monitored kinetically in the presence of the individual scavengers or in their combinations with epicatechin or cysteine. The observed and estimated reaction rate constants were calculated for each combination. As the observed rate constant for the reaction between cysteine and epicatechin was found to be significantly greater (p < 0.05) than the estimated rate constant, the results suggest synergism occurred in this combination. Epicatechin was found to interact antagonistically with scavengers that stimulate its oxidation such as creatine, quercetin, and gallic acid during methylglyoxal scavenging.


Assuntos
Catequina , Aldeído Pirúvico , Cisteína , Ácido Gálico , Humanos , Quercetina
5.
Phys Chem Chem Phys ; 23(34): 18843-18854, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34612422

RESUMO

The aggregation of amyloid-ß protein (Aß) into fibrillary deposits is implicated in Alzheimer's disease (AD), and inhibiting Aß aggregation and clearing Aß fibrils are considered as promising strategies to treat AD. It has been reported that resveratrol (RSV) and epigallocatechin-3-gallate (EGCG), two of the most extensively studied natural polyphenols, are able to inhibit Aß fibrillization and remodel the preformed fibrillary aggregates into amorphous, non-toxic species. However, the mechanisms by which RSV inhibits Aß42 aggregation and disrupts Aß42 protofibril, as well as the inhibitory/disruptive mechanistic similarities and differences between RSV and EGCG, remain mostly elusive. Herein, we performed extensive all-atom molecular dynamics (MD) simulations on Aß42 dimers (the early aggregation state of Aß42) and protofibrils (the intermediate of Aß42 fibril formation and elongation) in the absence/presence of RSV or EGCG molecules. Our simulations show that both RSV and EGCG can bind with Aß42 monomers and inhibit the dimerization of Aß42. The binding of RSV with Aß42 peptide is mostly viaπ-π stacking interactions, while the binding of EGCG with Aß42 is mainly through hydrophobic, π-π stacking, and hydrogen-bonding interactions. Moreover, both RSV and EGCG disrupt the ß-sheet structure and K28-A42 salt bridges, leading to a disruption of Aß42 protofibril structure. RSV mainly binds with residues whose side-chains point inwards from the surface of the protofibril, while EGCG mostly binds with residues whose side-chains point outwards from the surface of the protofibril. Furthermore, RSV interacts with Aß42 protofibrils mostly viaπ-π stacking interactions, while EGCG interacts with Aß42 protofibrils mainly via hydrogen-bonding and hydrophobic interactions. For comparison, we also explore the effects of RSV/EGCG molecules on the aggregation inhibition and protofibril disruption of the Iowa mutant (D23N) Aß. Our findings may pave the way for the design of more effective drug candidates as well as the utilization of cocktail therapy using RSV and EGCG for the treatment of AD.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Catequina/análogos & derivados , Simulação de Dinâmica Molecular , Resveratrol/farmacologia , Peptídeos beta-Amiloides/metabolismo , Catequina/química , Catequina/farmacologia , Humanos , Ligação de Hidrogênio , Agregados Proteicos/efeitos dos fármacos , Resveratrol/química
6.
Molecules ; 26(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34641495

RESUMO

Data obtained from several intensive care units around the world have provided substantial evidence of the strong association between impairment of the renal function and in-hospital deaths of critically ill COVID-19 patients, especially those with comorbidities and requiring renal replacement therapy (RRT). Acute kidney injury (AKI) is a common renal disorder of various etiologies characterized by a sudden and sustained decrease of renal function. Studies have shown that 5-46% of COVID-19 patients develop AKI during hospital stay, and the mortality of those patients may reach up to 100% depending on various factors, such as organ failures and RRT requirement. Catechins are natural products that have multiple pharmacological activities, including anti-coronavirus and reno-protective activities against kidney injury induced by nephrotoxic agents, obstructive nephropathies and AKI accompanying metabolic and cardiovascular disorders. Therefore, in this review, we discuss the anti-SARS-CoV-2 and reno-protective effects of catechins from a mechanistic perspective. We believe that catechins may serve as promising therapeutics in COVID-19-associated AKI due to their well-recognized anti-SARS-CoV-2, and antioxidant and anti-inflammatory properties that mediate their reno-protective activities.


Assuntos
Injúria Renal Aguda/etiologia , Antivirais/farmacologia , COVID-19/complicações , Catequina/farmacologia , Substâncias Protetoras/farmacologia , Injúria Renal Aguda/tratamento farmacológico , Animais , Antivirais/química , Antivirais/uso terapêutico , COVID-19/tratamento farmacológico , Catequina/química , Catequina/uso terapêutico , Humanos , Substâncias Protetoras/química , Substâncias Protetoras/uso terapêutico , SARS-CoV-2/efeitos dos fármacos
7.
Phytomedicine ; 92: 153752, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34601223

RESUMO

BACKGROUND: Cyclophosphamide (CTX), which has been used to treat common female cancers for several years, often causes ovarian damage, early menopause and infertility. However, strategies for the effective prevention and treatment of CTX-induced ovarian damage are still lacking. Epigallocatechin gallate (EGCG) and theaflavins (TFs), key molecules derived from green tea or black tea, have been shown to exert preventive effects on many ageing-related diseases. PURPOSE: We aimed to explore the potential preventive and protective effects of EGCG and TFs on CTX-induced ovarian damage and compare the two compounds. STUDY DESIGN: Six-week-old female mice were administered a low or high dose of EGCG or TFs. The low dose was equivalent to the average daily amount of tea consumed by a drinker. METHODS: We determined the oestrous cycle and serum hormone levels to evaluate ovarian endocrine function, and we performed mating tests for reproductivity. We also assessed the follicle count and AMH level to evaluate ovarian reserve, and we performed Masson's trichrome and Sirius red staining to evaluate ovarian fibrosis. We conducted γ-H2AX and TUNEL analyses to evaluate DNA damage, and we also measured the relevant indicators of oxidative stress and follicular activation, including NRF2, HO-1, SOD2, AKT, mTOR and RPS6. RESULTS: EGCG and TFs treatment independently improved the ovarian endocrine function and reproductivity of mice that were administered CTX. EGCG and TFs also increased the ovarian reserve of these animals. Furthermore, EGCG and TFs alleviated oxidation-induced damage to ovarian DNA in mice by activating the NRF2/HO-1 and SOD2 pathways and reducing the apoptosis of growing follicles. At the same time, EGCG and TFs reduced the overactivation of primordial follicles by inhibiting the AKT/mTOR/RPS6 pathway. CONCLUSION: The present study showed that EGCG and TFs independently improved ovarian function in mice with CTX-induced ovarian damage, thereby providing useful information for designing a potential clinical strategy that will protect against chemotherapy-induced ovarian damage.


Assuntos
Catequina , Atresia Folicular , Animais , Biflavonoides , Catequina/análogos & derivados , Catequina/farmacologia , Ciclofosfamida/toxicidade , Feminino , Camundongos
8.
Phytomedicine ; 92: 153754, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34607205

RESUMO

BACKGROUND: Bisphenol A (BPA) is an artificial chemical widely used in the production of polycarbonate plastics and epoxy resins. Accumulating evidence indicates that BPA exposure is associated with metabolic disorders. The beneficial effects of green tea and epigallocatechin gallate (EGCG), major catechin present in green tea, on alleviating BPA-induced metabolic disorders have been shown in various studies. PURPOSE: Protective effects of green tea extract and EGCG on BPA-induced metabolic disorders and possible underlying mechanisms were investigated. METHODS: Rats were randomly divided into control, green tea extract (50 and 100 mg/kg, IP), EGCG (20 and 40 mg/kg, IP), BPA (10 mg/kg, gavage), BPA plus green tea extract (25, 50, and 100 mg/kg, IP), BPA plus EGCG (10, 20, and 40 mg/kg, IP), and BPA plus vitamin E (200 IU/kg, IP). After two months, body weight, blood pressure, biochemical blood tests, hepatic malondialdehyde (MDA), and glutathione (GSH) were assessed. By enzyme-linked immunosorbent assay, serum levels of insulin, leptin, adiponectin, TNFα, and IL-6, and by western blotting, hepatic insulin signaling (IRS-1, PI3K, Akt) were measured. RESULTS: BPA increased body weight, blood pressure, and MDA, decreased GSH, elevated serum levels of low-density lipoprotein cholesterol, total cholesterol, triglyceride, glucose, insulin, leptin, TNFα, IL-6, and liver enzymes including alanine aminotransferase and alkaline phosphatase, and lowered high-density lipoprotein cholesterol and adiponectin levels. In western blot, decreased phosphorylation of IRS-1, PI3K, and Akt was obtained. Administration of green tea extract, EGCG, or vitamin E with BPA reduced the detrimental effects of BPA. CONCLUSION: These findings indicate that green tea extract and EGCG can be effective in preventing or reducing metabolic disorders induced by BPA linked to their antioxidant and anti-inflammatory activity, regulating the metabolism of lipids, and improving insulin signaling pathways.


Assuntos
Catequina , Doenças Metabólicas , Animais , Antioxidantes/farmacologia , Compostos Benzidrílicos , Catequina/análogos & derivados , Catequina/farmacologia , Doenças Metabólicas/induzido quimicamente , Doenças Metabólicas/tratamento farmacológico , Fenóis , Extratos Vegetais/farmacologia , Ratos , Chá
9.
J Agric Food Chem ; 69(41): 12209-12218, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34610737

RESUMO

Pterygium belongs to an ocular surface disease with triangular-shaped hyperplastic growth, characterized by conjunctivalization, inflammation, and connective tissue remodeling. We previously demonstrated neoplastic-like properties of pterygium cells. Green tea catechin, (-)-epigallocatechin gallate (EGCG), has been shown to possess antitumorigenic properties; herein, we aimed to determine the effects of green tea catechins on human primary pterygium cell survival and migration and compared to that on patients' conjunctival cells. Both human primary pterygium and conjunctival cells expressed EGCG receptor, the 67 kDa laminin receptor. Seven-day treatment of green tea extract (Theaphenon E; 16.25 µg/mL) and EGCG (25 µM) attenuated pterygium cell proliferation by 16.78% (p < 0.001) and 24.09% (p < 0.001) respectively, without significantly influencing conjunctival cells. Moreover, green tea extract (16.25 µg/mL) and EGCG (25 µM) treatments also hindered pterygium cell migration by 35.22% (p < 0.001) and 25.20% (p = 0.019), respectively, but not conjunctival cells. Yet, green tea extract and EGCG treatments did not significantly induce pterygium cell apoptosis. Furthermore, green tea extract and EGCG treatments significantly increased the phosphorylation of p38 protein but reduced the phosphorylation of p42/p44 protein in pterygium cells. In summary, this study revealed that green tea extract and EGCG attenuated human primary pterygium cell survival and migration in vitro without damaging conjunctival cells, suggesting a novel potential therapeutic approach for primary pterygium treatment.


Assuntos
Catequina , Pterígio , Catequina/farmacologia , Proliferação de Células , Sobrevivência Celular , Humanos , Pterígio/tratamento farmacológico , Pterígio/genética , Chá
10.
J Agric Food Chem ; 69(41): 12314-12322, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34612625

RESUMO

Phytoferritin has a natural cagelike architecture for carrying bioactive molecules, and it is uniquely suited to function as a carrier due to its multiple interfaces and channels. In this study, a novel approach was proposed to prepare ferritin-salvianolic acid B-epigallocatechin gallate (EGCG) three-layer nanoparticles (FSE) through the steric hindrance of ferritin channels. Urea (30 mM) could expand the ferritin channel size evidenced by the improved iron release rate vo and promote the EGCG penetration into the ferritin cavity without disassembly of the ferritin cage. The encapsulation ratio of EGCG was 16.0 ± 0.14% (w/w). Salvianolic acid B attached to the outer interface of ferritin through weak bonds with a binding constant of (2.91 ± 0.04) × 105 M-1. The FSE maintained a spherical structure with a diameter of 12 nm. Moreover, when subjected to heat (40-70 °C) there was a significant increase in the stability of EGCG in the FSE due to the binding of salvianolic acid B. Through this interesting approach, two molecules are simultaneously attached and encapsulated in ferritin in a multilayer form under moderate conditions, which is conducive to the protection of unstable molecules for potential encapsulation and delivery utilization.


Assuntos
Catequina , Nanopartículas , Benzofuranos , Catequina/análogos & derivados , Ferritinas
11.
Food Res Int ; 148: 110587, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507732

RESUMO

Epigallocatechin gallate (EGCg) and methylxanthines are representative bioactive compounds in tea leaves, the strong affinity between them will elicit destruction of tea quality. In order to elucidate the mechanism of complexation between EGCg and methylxanthines, we compared the bindings of theophylline and caffeine to EGCg by nuclear magnetic resonance (NMR), molecular docking and isothermal titration calorimetry (ITC). The results revealed that the stoichiometries of caffeine to EGCg and theophylline to EGCg were both 1:1. Caffeine and theophylline were captured in the hydrophobic space formed by aromatic rings of EGCg. The affinity between EGCg and caffeine was stronger than that between EGCg and theophylline, which could be partially attributed to the two extra CH-π interactions between N7-Me of caffeine and aromatic rings of EGCg. Furthermore, the results of ITC were agreed well with NMR and molecular docking, indicating that ITC was possible to accurately evaluate the complexation.


Assuntos
Cafeína , Catequina , Catequina/análogos & derivados , Espectroscopia de Ressonância Magnética , Simulação de Acoplamento Molecular , Teofilina , Termodinâmica
12.
Food Res Int ; 148: 110588, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507733

RESUMO

Monosaccharides of Keemun black tea were quantitatively determined by high performance liquid chromatography coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one (PMP) pre-column derivatization. The methodology of developed analytical method was established with good linearity, recovery, repeatability and precision. The quantitative results showed that D-mannose, D-glucuronic acid, D-glucose, D-galactose and L-arabinose were detected in Keemun black tea samples. D-glucose was the predominant monosaccharide in black tea, and its concentration was continuously increased from fresh tea leaves to fermentation, but after drying its concentration was significantly decreased. Meanwhile, theaflavins' concentrations were obviously decreased after drying. When theaflavins were heated with D-glucose, the loss of theaflavins was increased. Correspondingly, theaflavins also prevented the caramelization of D-glucose and restored the loss of D-glucose during heating. Through the liquid chromatography/electrospray tandem mass spectrometry some theaflavins glucose adducts were identified.


Assuntos
Biflavonoides , Chá , Biflavonoides/análise , Catequina , Glucose , Monossacarídeos
13.
J Agric Food Chem ; 69(38): 11417-11426, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34519500

RESUMO

During tea processing, roasting significantly affects the transformation pathway of catechins. When (-)-epigallocatechin gallate (EGCG) and glucose were roasted at different pH values, the degree of degradation and isomerization of EGCG was the lowest at pH 7 and the highest at pH 8. Thirty-five products were found in the model reaction of EGCG and glucose under high temperatures, of which four EGCG-glucose adducts were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR). In addition, catechins, gallic acid, and theanine in tea with added glucose were significantly reduced during roasting. The contents of four EGCG-glucose adducts were increased significantly at 150 °C after 30 min and dropped gradually after 60 min. Therefore, based on the present study, EGCG could form crosslinks with glucose under high temperatures in a short time, which provides insight for tea processing and synthesis of catechin-sugar adducts.


Assuntos
Catequina , Cromatografia Líquida , Glucose , Pós , Espectrometria de Massas em Tandem , Chá , Temperatura
14.
Arch Oral Biol ; 131: 105268, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34571395

RESUMO

OBJECTIVES: The dentin therapeutic agent chlorhexidine has inflammatory and cytotoxic characteristics urging investigation of alternatives like the natural compound epigallocatechin-gallate. The aim is to verify the effect of epigallocatechin-gallate and chlorhexidine on viability, interleukin-1ß (IL-1ß) and differential protein expression of MDPC-23 odontoblast-like cells stimulated by Streptococcus mutans. DESIGN: Cells were stimulated with heat-killed S. mutans at multiplicity of infection (MOI) of 100-1000 and subsequently treated with 100-1 µM of epigallocatechin-gallate. Cells with no treatment or chlorhexidine were controls. Combined stimulated/treated cells were tested for cytotoxicity (Alamar-Blue, N = 3, n = 3), total protein (N = 3, n = 3), IL-1ß (ELISA, N = 3, n = 3), and differential protein expression by liquid chromatography-tandem mass spectrometry (LC-MS/MS, n = 2). RESULTS: Cells stimulated at MOI 100/1000 and treated with 10 µM epigallocatechin-gallate and chlorhexidine did not present cytotoxicity. IL-1ß significantly increased in both un-stimulated and stimulated chlorhexidine 10 µM groups when compared to un-treated control (p < 0.05). MOI 100 chlorhexidine 10 µM group significantly increased IL-1ß compared to un-stimulated chlorhexidine 10 µM and epigallocatechin-gallate 10 µM groups, as well as to MOI 100 epigallocatechin-gallate 10 µM group (p < 0.05). LC-MS/MS revealed S. mutans and mammalian proteins, with tooth-specific proteins exhibiting different abundance levels, depending on the tested condition. CONCLUSIONS: Odontoblast-like cells stimulated with S. mutans at different MOI combined with epigallocatechin-gallate treatment did not cause cytotoxicity. S. mutans stimulation combined with chlorhexidine 100 µM treatment decreased cell viability, while treatment with chlorhexidine 10 µM concentration significantly increased IL-1ß. S. mutans stimulation and treatment of cells resulted in varied protein expression.


Assuntos
Catequina , Streptococcus mutans , Animais , Catequina/análogos & derivados , Catequina/farmacologia , Clorexidina/toxicidade , Cromatografia Líquida , Interleucina-1beta , Odontoblastos , Proteômica , Espectrometria de Massas em Tandem
15.
Langmuir ; 37(36): 10818-10826, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34470217

RESUMO

Direct visualization of the dynamic events in lysosomes during drug-mediated programmed cell death (apoptosis) is a great challenge. This is due to the lack of resolving power of a conventional microscope and also the unavailability of a suitable multimodal probe that simultaneously can carry the drug with high loading capacity and ensure its specific internalization into lysosomes. In this work, using super-resolution microscopy, we observed the lysosomal expansion during apoptosis that was treated with epigallocatechin gallate (EGCG) conjugated to bovine serum albumin (BSA). Albumin protein is known to internalize into lysosomes via endocytosis, thus helping in the specific delivery of EGCG to the lysosomal compartment. The conjugation of EGCG to BSA not only helped in increasing the killing efficiency of cancer cells but it also reduces the side effects and produces minimal reactive oxygen species. The decrease in local viscosity helped in lysosomal expansion during apoptosis.


Assuntos
Catequina , Microscopia , Apoptose , Catequina/análogos & derivados , Lisossomos , Espécies Reativas de Oxigênio
16.
Plant Sci ; 311: 110997, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34482909

RESUMO

Yunnan Province has a very wide diversity of tea germplasm resources. A variety of special tea germplasms with outstanding traits have been discovered, including tea germplasms with high anthocyanin content and low caffeine content. Albino tea cultivars generally have higher contents of theanine that contribute to the umami taste, and the quality of tea brewed from it is higher. The catechin index (CI), the ratio of dihydroxylated catechins (DIC) to trihydroxylated catechins (TRIC), is a crucial index of suitability for processing tea. In this study, the albino tea plant Menghai Huangye (MHHY) with yellow leaves was identified. Analysis of the biochemical components revealed that MHHY was enriched in theanine and the total catechins (TC) were lower than Yunkang 10 (YK10). In addition, the CI value of MHHY was extremely significantly higher than that of YK10. Metabolic profile of catechins and the related gene expression profile analysis found that the coordinated expression of the key branch genes F3'H and F3'5'Ha for the synthesis of DIC and TRIC in tea plant was closely related to the high CI and low TC of MHHY. Further analysis of the F3'H promoter showed that a 284-bp deletion mutation was present in the F3'H promoter of MHHY, containing the binding sites of the transcriptional repressor MYB4 involved in flavonoid metabolism, which might be an important reason for the up-regulated expression of F3'H in MHHY. Overall, this study provides a theoretical basis for understanding the characteristics of albino tea germplasm resources and efficiently utilizing high-CI tea germplasm resources.


Assuntos
Camellia sinensis/anatomia & histologia , Camellia sinensis/genética , Catequina/análise , Glutamatos/análise , Pigmentação/genética , Catequina/genética , Genes de Plantas , Variação Genética , Genótipo , Glutamatos/genética , Fenótipo , Transcriptoma
17.
Drug Res (Stuttg) ; 71(8): 462-472, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34517419

RESUMO

BACKGROUND: Replication of SARS-CoV-2 depends on viral RNA-dependent RNA-polymerase (RdRp). Remdesivir, the broad-spectrum RdRp inhibitor acts as nucleoside-analogues (NAs). Remdesivir has initially been repurposed as a promising drug against SARS-CoV-2 infection with some health hazards like liver damage, allergic reaction, low blood-pressure, and breathing-shortness, throat-swelling. In comparison, theaflavin-3'-O-gallate (TFMG), the abundant black tea component has gained importance in controlling viral infection. TFMG is a non-toxic, non-invasive, antioxidant, anticancer and antiviral molecule. RESULTS: Here, we analyzed the inhibitory effect of theaflavin-3'-O-gallate on SARS CoV-2 RdRp in comparison with remdesivir by molecular-docking study. TFMG has been shown more potent in terms of lower Atomic-Contact-Energy (ACE) and higher occupancy of surface area; -393.97 Kcal/mol and 771.90 respectively, favoured with lower desolvation-energy; -9.2: Kcal/mol. TFMG forms more rigid electrostatic and H-bond than remdesivir. TFMG showed strong affinity to RNA primer and template and RNA passage-site of RdRp. CONCLUSIONS: TFMG can block the catalytic residue, NTP entry site, cation binding site, nsp7-nsp12 junction with binding energy of -6. 72 Kcal/mol with Ki value of 11.79, and interface domain with binding energy of -7.72 and -6.16 Kcal/mol with Ki value of 2.21 and 30.71 µM. And most importantly, TFMG shows antioxidant/anti-inflammatory/antiviral effect on human studies.


Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Antivirais/farmacologia , Biflavonoides/farmacologia , COVID-19/tratamento farmacológico , Catequina/farmacologia , RNA-Polimerase RNA-Dependente de Coronavírus/antagonistas & inibidores , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Ácido Gálico/análogos & derivados , Simulação de Acoplamento Molecular , SARS-CoV-2/efeitos dos fármacos , Monofosfato de Adenosina/química , Monofosfato de Adenosina/farmacologia , Alanina/química , Alanina/farmacologia , Antivirais/química , Biflavonoides/química , COVID-19/virologia , Domínio Catalítico , Catequina/química , RNA-Polimerase RNA-Dependente de Coronavírus/metabolismo , Inibidores Enzimáticos/química , Ácido Gálico/química , Ácido Gálico/farmacologia , Conformação Proteica , SARS-CoV-2/enzimologia , Relação Estrutura-Atividade
18.
BMC Oral Health ; 21(1): 447, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34525984

RESUMO

BACKGROUND: Streptococcus mutans (S. mutans) plays a major role in the formation of dental caries. The aim of this study was to examine the effect of the green tea polyphenol, epigallocatechin gallate (EGCG), on biofilm formation of S. mutans. METHODS: Following exposure to increasing concentrations of EGCG, the planktonic growth was measured by optical density and the biofilm biomass was quantified by crystal violet staining. Exopolysaccharides (EPS) production was visualized by confocal scanning laser microscopy, and the bacterial DNA content was determined by quantitative polymerase chain reaction (qPCR). Gene expression of selected genes was analyzed by real time (RT)-qPCR and membrane potential was examined by flow cytometry. RESULTS: We observed that EGCG inhibited in a dose-dependent manner both the planktonic growth and the biofilm formation of S. mutans. Significant reduction of S. mutans biofilm formation, DNA content, and EPS production was observed at 2.2-4.4 mg/ml EGCG. EGCG reduced the expression of gtfB, gtfC and ftf genes involved in EPS production, and the nox and sodA genes involved in the protection against oxidative stress. Moreover, EGCG caused an immediate change in membrane potential. CONCLUSIONS: EGCG, a natural polyphenol, has a significant inhibitory effect on S. mutans dental biofilm formation and EPS production, and thus might be a potential drug in preventing dental caries.


Assuntos
Catequina , Cárie Dentária , Biofilmes , Catequina/análogos & derivados , Catequina/farmacologia , Humanos , Streptococcus mutans/genética
19.
Nan Fang Yi Ke Da Xue Xue Bao ; 41(8): 1158-1164, 2021 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-34549705

RESUMO

OBJECTIVE: To explore whether procyanidin B2 (PCB2) regulates the P13K/Akt/Nrf2 signaling pathway to protect neurons from oxidative stress induced by cypermethrin (CYP). METHODS: Primary cultures of cerebral cortex neurons from C57BL/6 mice were randomly divided into 5 groups: normal control group (cultured in serum-free neurobasal-B27 medium), PCB2 treatment group(treated with 5 µg/mL PCB2 for 24 h), CYP exposure group(treated with 50 µmol/L CYP for 24 h), PCB2 pretreatment group(pretreated with 5 µg/mL PCB2 for 30 min followed by exposure to 50 µmol/L CYP for 24 h), and LY294002 treatment group (pretreated with 20 µmol/L LY294002 for 30 min before treatment with PCB2 for 30 min and then CYP for 24 h).CCK-8 assay was used to analyze the neuronal viability after the treatments.Reactive oxygen species (ROS) production in the cells was detected using the fluorescent probe DCFH-DA and flow cytometry.The changes in nuclear morphology and mitochondrial membrane potential of the cells were examined with Hoechst 33342 and JC-1 staining, respectively.Western blotting was performed to detect the protein expressions of Nrf2, HO-1, p-Akt and Akt in the cells. RESULTS: In CYP exposure group, the cells showed significantly decreased viability and mitochondrial membrane potential with obvious apoptotic morphological changes and abnormal ROS production.By comparison, the cells in PCB2 preconditioning group showed improved cell survival rate, reduced abnormalities in nuclear morphology, increased mitochondrial membrane potential, and lowered intracellular ROS production.CYP exposure caused Nrf2 nuclear translocation and up-regulated Nrf2, HO-1, p-Akt protein expressions in the cells, which were inhibited by PCB2 pretreatment.Inhibition of the P13K/Akt signaling pathway obviously neutralized the protective effect of PCB2 against CYP-induced neuronal injury. CONCLUSIONS: PCB2 regulates the Nrf2/ARE signaling pathway by activating the P13K/Akt signaling pathway to protect mouse cerebral cortical neurons against oxidative injury induced by cypermethrin.


Assuntos
Fator 2 Relacionado a NF-E2 , Proteínas Proto-Oncogênicas c-akt , Animais , Apoptose , Biflavonoides , Catequina , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/metabolismo , Estresse Oxidativo , Proantocianidinas , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piretrinas , Espécies Reativas de Oxigênio , Transdução de Sinais
20.
J Agric Food Chem ; 69(37): 11074-11084, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34499505

RESUMO

The present study investigated the potential of free radical grafting conjugation of whey protein isolate (WPI) and (-)-epigallocatechin-3-gallate (EGCG), followed by freeze-drying, for the safe delivery of probiotic Lactobacillus acidophilus (LA) upon digestion and in food systems. WPI-EGCG-LA microspheres presented higher encapsulation efficiency (97%) than native WPI-LA (70%) and maltodextrin (MD-LA 75%). The physicochemical characteristics of all microspheres, including moisture content, water activity, and hygroscopicity, were within the acceptable range for the stability of industrial powders. Scanning electron microscopy of WPI-EGCG-LA revealed a glass-like structure, with a smoother and less porous surface area than WPI-LA and MD-LA, as a result of the strong binding affinity between WPIs and EGCG. Particle sizes ranged from 438.4 to 453.3 µm. The structural stability of WPI-EGCG-LA was further confirmed by Fourier transform infrared spectra, which revealed some changes in the protein secondary structure. Thermogravimetric and differential scanning calorimetry analysis showed that WPI-EGCG conjugates had higher thermal stability than native WPIs and MD. Additionally, cells encapsulated in WPI-EGCG conjugates demonstrated higher in vitro survivability and surface hydrophobicity compared to free or WPI- and MD-encapsulated cells. Furthermore, WPI-EGCG-LA microspheres exerted enhanced in vitro antioxidant (78%) and antidiabetic (52%) activities. Finally, the WPI-EGCG conjugates remarkably improved probiotic viability (8.55 ± 0.1 log cfu/g) during 30 days of storage in an apple juice drink of pH (3.2 ± 0.01). Hence, the WPI-EGCG conjugate represents a propitious carrier to enhance probiotic functional properties upon digestion and during storage in low-pH food products.


Assuntos
Catequina , Probióticos , Catequina/análogos & derivados , Lactobacillus acidophilus , Proteínas do Soro do Leite
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