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1.
Food Chem ; 399: 133727, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36027815

RESUMO

(-)-Epigallocatechin-3-gallate (EGCG) was conjugated to whey protein isolate (WPI) using alkaline treatment, free radical grafting and tyrosinase-catalyzed oxidation. The structure and properties of the obtained conjugates and their application as antioxidant emulsifiers in stabilizing ß-carotene emulsion were systematically characterized. Fourier transform infrared spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis verified the covalent linking between WPI and EGCG. The highest grafting efficiency was obtained for enzyme conjugate, followed for alkaline conjugate. Conjugation of EGCG decreased the α-helix content and fluorescence intensity of protein, and these changes depend on both EGCG conjugation and the cross-linking methods. Due to their improved emulsifying properties and antioxidant activity, WPI-EGCG conjugates formed smaller emulsion droplets and protect the encapsulated ß-carotene more effectively, and the protective property is positively correlated with EGCG content in conjugates.


Assuntos
Catequina , beta Caroteno , Antioxidantes/química , Catequina/análogos & derivados , Catequina/química , Emulsões/química , Proteínas do Soro do Leite/química , beta Caroteno/química
2.
Food Chem ; 399: 133927, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36029674

RESUMO

Copigmentation effect of flavonoids on black mulberry juice and its main anthocyanin, cyanidin-3-O-glucoside (C3G), was evaluated. Results showed that the hyperchromic effect of flavonols, such as kaempferol (KAE), hyperoside (HYP), rutin (RUT), quercetin (QTI) and isoquercitrin (IQT), was better than that of quercitrin (QTR) and catechin (CAT). The degradation rate constant (k) of C3G decreased by 8.6 %∼50.0 % when KAE, HYP, RUT, QTI and IQT were added, whilst half-life (t1/2), activation energy (Ea) and hydration reaction equilibrium constant (pKh) increased by 7.4 %∼99.0 %, 60.0 %∼95.7 % and 8.3 %∼37.8 % respectively. Meanwhile, the maximum absorption wavelength of the mixture displayed bathochromic shift. Molecular simulation indicated that the interaction energy with C3G was KAE > HYP > RUT > QTI > IQT > QTR > CAT. The main driving force forming C3G-flavonol complex were hydrogen bond and Van der Waals interaction. These results will provide theoretical reference to enhance color stability of food rich in anthocyanins.


Assuntos
Catequina , Morus , Antocianinas/análise , Catequina/química , Flavonoides/análise , Flavonóis/análise , Frutas/química
3.
Food Chem ; 399: 133933, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36037684

RESUMO

A series of incubation systems of (+) - catechin (Cat), ascorbic acid (AA) and polyphenol oxidase (PPO) of lotus rhizome at 40 °C were performed to investigate the effect and oxidation pathway of AA on the stability of Cat. The results showed that after the enzymatic or non-enzymatic oxidation of Cat, the products of the two reactions were the same, namely epicatechin, catechin dimer and dehydrogenated catechin dimer. After adding AA, the protective effect of AA on catechin increased first and then decreased with the increase of AA concentration. 0.1 mmolL(exp)-1 AA can inhibit PPO activity in a short time. Within 24 h, 1 mmolL(exp)-1 AA can keep Cat content at 87.88 %. At the concentration of 10 mmolL(exp)-1 AA, excessive AA is oxidized to form a large amount of dehydroascorbic acid (DHAA), which forms an adduct with Cat, promoting the consumption of Cat. The effect of AA on the stability of Cat is time-dependent and dose-dependent.


Assuntos
Ácido Ascórbico , Catequina , Ácido Ascórbico/metabolismo , Catecol Oxidase/metabolismo , Ácido Desidroascórbico , Oxirredução
4.
J Nutr Biochem ; 111: 109179, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36223832

RESUMO

Epigallocatechin gallate (EGCG) has a wide consumption for its health advantages. The current study investigates the effects of prenatal EGCG administration on glucose metabolism and obesity in adulthood. Pregnant C57BL/6J mice were supplemented with EGCG in drinking water (3 µg/mL) for 16 d. Abdominal obesity was observed in both male and female adult mice, which was associated with the upregulation of adipose-specific genes, including C/ebpα and Srebf1 (Srebf1 only in males), and the downregulation of genes related to lipolysis, such as Acox1, Atgl and Pdk4 (only in males) in visceral adipose tissue. Elevated fasting glucose levels and hyperinsulinemia were observed in adult males, while females exhibit lower glucose level in glucose tolerance test, which might be due to reduced glucagon levels. Though hepatic expression of the insulin receptor signaling pathway was upregulated in males and was not altered in females, prenatal treatment with EGCG downregulated the expression of this signaling pathway in the skeletal muscle of adult mice, which was further demonstrated in primary human skeletal muscle cells treated with EGCG. The methylation levels in promotor of genes related to the insulin receptor signaling were matched with their transcription in mice, while the expression of acetylated histones was downregulated in human skeletal muscle cells. These results suggest that EGCG consumption during pregnancy should be a risk factor for the disruption of glucose homeostasis in adulthood.


Assuntos
Catequina , Obesidade , Efeitos Tardios da Exposição Pré-Natal , Adulto , Animais , Feminino , Masculino , Camundongos , Gravidez , Catequina/farmacologia , Glucose/metabolismo , Homeostase , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Receptor de Insulina
5.
Environ Res ; 216(Pt 2): 114478, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36206926

RESUMO

In this study, the effect of bay laurel (Laurus nobilis) (LE) and rosemary (Salvia rosmarinus) (RE) extracts, in two free forms and loaded with liposome, on the behavior of Listeria monocytogenes and Vibrio parahaemolyticus in silver carp (Hypophthalmichthys molitrix) minced, were examined. After extraction, the extracts were evaluated for phenolic, flavonoid, and antibacterial compounds (determination of MIC and MBC). The treatments studied included control treatment, treatments containing 1 and 1.5% of free extracts, and treatments containing 1 and 1.5% of liposome-coated extracts of LE and RE which were examined at times of 0, 4, 8, and 12 days with 3 replications. The findings indicated that the amount of flavonoid and phenolic compounds and the results of antibacterial tests (MIC and MBC tests) in RE extract were more favorable than LE extract. The aqueous extract of rosemary had higher levels of phenolic (344.66 mg gallic acid/g extract) and flavonoid (245.33 mg Catechin/g extract) compounds compared to the bay laurel extract (257.66 mg gallic acid/g extract) and (151.26 mg Catechin/g extract) respectively. The results of the behavior of L. monocytogenes and V. parahaemolyticus in fish showed that with increasing the storage time at 4 °C, these parameters increased, but in the treatment containing the coated forms of LE and RE extracts (concentration 1.5%), changes were significantly slower than other treatments. According to the obtained results, it can be concluded that in general, adding extracts of bay laurel and rosemary in a concentration of 1.5% reduces the proliferation of bacteria that cause food poisoning.


Assuntos
Carpas , Catequina , Laurus , Listeria monocytogenes , Rosmarinus , Salvia , Vibrio parahaemolyticus , Animais , Lipossomos/farmacologia , Catequina/farmacologia , Extratos Vegetais/farmacologia , Fenóis , Antibacterianos/farmacologia , Flavonoides/farmacologia , Ácido Gálico
6.
Food Chem ; 404(Pt B): 134614, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36444092

RESUMO

The utilisation of quinoa protein concentrates (QPCs) is limited due to their poor protein digestibility (78.54 %). In this study, QPCs (1 % w/v) were fermented in 5 % (v/v) water kefir grains (WKG) for 5 days at 25 °C. The protein quality of the fermented QPCs was enhanced, whereby the protein digestibility increased significantly (P < 0.05) from 78.54 to 87.67 % after 5 days of fermentation and significant (P < 0.05) changes to the secondary protein structure components (α-helix and random coil). Concurrently, saponins content and pH decreased significantly (P < 0.05). After 2 days of fermentation, the total phenolic content increased significantly (P < 0.05) from 314.5 to 528.8 mg of GAE/100 g. Various phenolic compounds were detected, with epicatechin being the most abundant in the fermented QPCs. WKG fermentation posed as a potential reliable method for enhancing the quality and protein structure of QPCs.


Assuntos
Catequina , Chenopodium quinoa , Kefir , Água , Fermentação , Fenóis
7.
Food Chem ; 405(Pt B): 134600, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-36403476

RESUMO

The effects of Pulsed Light (PL) technology on the anthocyanin condensation reaction in model wine solutions were investigated. Model wine solutions containing malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside were separately prepared with the presence of (-)-epicatechin and acetaldehyde. The solutions were subjected to PL treatment with 2, 4, and 8 J/cm2 energy and stored in 10 °C. The loss of anthocyanin during the treatment and the aging period fitted the first-order reaction model (R2 > 98 %). Delphinidin-3-O-glucoside suffered the highest loss, only 46 % remaining after 60 s treatment; the malvidin-3-O-glucoside showed the lower loss, 72 % remaining after 60 s treatment. Furthermore, the PL treatment significantly influenced the kinetics of anthocyanin loss. The results from LC ESI TOF/Q-TOF MS/MS analysis revealed that in the PL treated samples, more peaks eluted in the chromatogram assigned to anthocyanin ethyl-linked (-)-epicatechin products, suggesting that PL treatment led to the formation of new isomers of anthocyanin ethyl-linked (-)-epicatechin. The color characteristics of the model solutions were affected by the PL treatment and the formation of ethyl-linked products. For example, the ΔE* value for samples treated with 8 J/cm2 increased by 42.52, 55.73, and 45.61 % for malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside respectively after 110 days.


Assuntos
Catequina , Vinho , Antocianinas , Cinética , Espectrometria de Massas em Tandem , Glucosídeos
8.
Food Chem ; 403: 134340, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36166928

RESUMO

Herein, a new indicator-displacement array (IDA) sensor was developed for the quality evaluation of black tea fermentation. On the principle of the reversible covalent binding of phenylboronic acid and catechol, phenylboronic acids were selected as acceptors for targeted binding to polyphenols. Pyrocatechol violet and alizarin red S were used as indicators of the reaction. The IDA sensors have sensitive differential responses to fermented tea samples, achieving an assessment of the fermentation degree with accuracies of 80.39-88.00% by support vector machine (SVM). In addition, the key polyphenol components of the fermentation process were accurately predicted by the IDA and SVM regression with ratio of prediction to deviation values of 1.55-1.72, 2.03-2.21, and 2.03-2.08 for total polyphenols, total catechins, and epigallocatechin-3-O-gallate, respectively. In conclusion, the developed IDA sensor is capable of the in-situ quality monitoring of black tea fermentation, with the advantages being cost-effectiveness, sensitivity, and rapidity.


Assuntos
Camellia sinensis , Catequina , Chá , Polifenóis/análise , Análise Custo-Benefício , Fermentação , Catequina/análise
9.
Braz. j. biol ; 83: e248746, 2023. graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339351

RESUMO

Abstract Colorectal cancer (CRC) is one of the most common cancers leading to comorbidities and mortalities globally. The rational of current study was to evaluate the combined epigallocatechin gallate and quercetin as a potent antitumor agent as commentary agent for therapeutic protocol. The present study investigated the effect of epigallocatechin Gallate (EGCG) (150mg) and quercetin (200mg) at different proportions on proliferation and induction of apoptosis in human colon cancer cells (HCT-116). Cell growth, colonogenic, Annexin V in addition cell cycle were detected in response to phytomolecules. Data obtained showed that, the colony formation was inhibited significantly in CRC starting from the lowest concentration tested of 10 µg/mL resulting in no colonies as visualized by a phase-contrast microscope. Data showed a significant elevation in the annexin V at 100 µg/mL EGCG(25.85%) and 150 µg/mL quercetin (48.35%). Moreover, cell cycle analysis showed that this combination caused cell cycle arrest at the G1 phase at concentration of 100 µg/mL (72.7%) and 150 µg/mL (75.25%). The combined effect of epigallocatechin Gallate and quercetin exert antiproliferative activity against CRC, it is promising in alternative conventional chemotherapeutic agent.


Resumo O câncer colorretal (CCR) é um dos cânceres mais comuns, levando a comorbidades e mortalidade em todo o mundo. O racional do presente estudo foi avaliar a combinação de galato de epigalocatequina e quercetina como um agente antitumoral potente como agente de comentário para protocolo terapêutico. O presente estudo investigou o efeito de galato de epigalocatequina (EGCG) (150 mg) e quercetina (200 mg) em diferentes proporções na proliferação e indução de apoptose em células de câncer de cólon humano (HCT-116). O crescimento celular, colonogênico, anexina V, além do ciclo celular foram detectados em resposta a fitomoléculas. Os dados obtidos mostraram que a formação de colônias foi inibida significativamente no CRC a partir da concentração mais baixa testada de 10 µg/mL, resultando em nenhuma colônia conforme visualizado por um microscópio de contraste de fase. Os dados mostraram uma elevação significativa na anexina V a 100 µg/mL de EGCG (25,85%) e 150 µg/mL de quercetina (48,35%). Além disso, a análise do ciclo celular mostrou que essa combinação causou parada do ciclo celular na fase G1 na concentração de 100 µg/mL (72,7%) e 150 µg/mL (75,25%). O efeito combinado da epigalocatequina galato e quercetina exerce atividade antiproliferativa contra o CCR, é promissor como agente quimioterápico alternativo convencional.


Assuntos
Humanos , Neoplasias Colorretais/tratamento farmacológico , Catequina/análogos & derivados , Catequina/farmacologia , Quercetina/farmacologia , Ciclo Celular , Anexina A5 , Linhagem Celular Tumoral , Proliferação de Células
10.
J Ethnopharmacol ; 300: 115742, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36152784

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Despite widespread use of herbal remedies for treating arthritis and osteosarcoma, many plants are still not pharmacologically evaluated for their efficacy. Contrary to many non-steroidal, immunosuppressants, antibiotics, and antineoplastic drugs that have adverse effects, phytotherapeutic compounds have promising benefits with fewer complications. In this study the unexplored Northeastern India indigenous plant Trevesia palmata (Roxb. ex Lindl.) Vis. used in traditional medicine to cure bone fractures is chosen for studying anti-proliferative and anti-rheumatic properties. AIM OF THE STUDY: This study designed to explore the polyphenolic composition, antioxidant, anti-inflammatory and anti-arthritic potential of T. palmata leaf extracts. Further, the cellular activity was studied using MG 63 osteoblast cell lines and pharmacologically evaluated using Complete Freund's Adjuvant (CFA) induced arthritic rat model. MATERIALS AND METHODS: In vitro free radical scavenging activity, anti-inflammatory and anti-arthritic activities of extracts were analyzed using standardized methods. The polyphenolic profiling and apoptosis inducing ability of T. palmata ethyl acetate (TPEA) extract on MG 63 osteoblast cell lines were analyzed. The in vivo pharmacological studies were carried out with low dose 250 mg/kg and high dose of 500 mg/kg of T. palmata. The biochemical and haematological parameters and in vivo antioxidant activity were evaluated for the control and treated groups. Radiological and histological study were done to understand the impact and penetration of inflammatory arthritis from tissues to joint bones. RESULTS: TPEA showed highest free radical scavenging activity (DPPH - 4.72 IC50, ABTS - 242.33 ± 6.81 mM TE/g extract), anti-inflammatory (40.04% inhibition of RBC lysis) and anti-arthritic activity (32.4% inhibition of protein denaturation) with the presence of gallic acid, catechin, caffeic acid, rutin, quercetin and naringenin. The TPEA extract inhibited cell proliferation of MG 63 osteoblast cells and induced apoptosis by arresting cell cycle at different phases. After acute toxicity studies the doses 250 mg/kg and 500 mg/kg were fixed and showed better results in CFA-induced arthritic animals. Thus, the extract phytoconstituents may have immense potential against chronic inflammation, joint ailments, bone cancer and arthritis which serves as a phytomedicine contrary to synthetic medications. CONCLUSIONS: The potential treatment of polyphenolic compounds in the T. palmata extract on osteosarcoma and arthritis was demonstrated from this study. Thus, cellular inflammatory infiltrates are significantly reduced in bone and joint tissues as well.


Assuntos
Araliaceae , Artrite Experimental , Catequina , Osteossarcoma , Animais , Antibacterianos/uso terapêutico , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Artrite Experimental/tratamento farmacológico , Artrite Experimental/patologia , Linhagem Celular , Radicais Livres , Adjuvante de Freund , Ácido Gálico/uso terapêutico , Imunossupressores , Osteossarcoma/tratamento farmacológico , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Quercetina/uso terapêutico , Ratos , Rutina
11.
Food Chem ; 404(Pt B): 134672, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36323025

RESUMO

This study aimed to identify novel pancreatic lipase (PL) inhibitors using affinity ultrafiltration combined with spectroscopy and molecular docking. Cyanidin-3-O-glucoside (C3G; IC50: 0.268 mg/mL) and catechin (IC50: 0.280 mg/mL) were shown to be potent PL inhibitors extracted from black rice and adzuki bean coat extracts. Isobologram analysis revealed that the combined use of C3G and catechin at a ratio of 2:3 had a remarkable synergistic effect (IC50 of the mixture: 0.201 mg/mL). The inhibitory mechanism of C3G-catechin mixture was of mixed type. The C3G-catechin mixture had a great impact on PL secondary structures. Molecular docking analysis further demonstrated that these polyphenols formed hydrophobic interactions and hydrogen bonds with amino acid residues in the binding pocket of PL. Collectively, C3G and catechin were shown to inhibit PL in a synergistic manner and can be potentially used for the development of food supplements for obesity prevention.


Assuntos
Catequina , Catequina/farmacologia , Catequina/química , Lipase , Simulação de Acoplamento Molecular , Glucosídeos/química , Antocianinas/química
12.
Food Chem ; 404(Pt B): 134773, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36332583

RESUMO

Liupao tea is a dark tea with unique quality. Semi-finished Liupao tea with two different fermentation processes (traditional/tank) was analyzed to explain the chemical characteristics and taste quality. The content change rate of polyphenols, flavonoids, and theabrownin in traditional fermentation was approximately twice that in tank fermentation. Electronic tongue revealed that bitterness and astringency increased, whereas aftertaste-astringency decreased after fermentation. 36 compounds were identified as the biomarkers responsible for the metabolic changes caused by fermentation with significant decrements in catechins, catechin gallate, and α, α-trehalose, and significant increments in gallic acid content (VIP > 3; P < 0.05). In addition, 26 metabolites were identified to distinguish between tank and traditional fermentation, with correlation analysis indicating that catechin gallate, epicatechin and gallic acid accounting for the differences in taste between the two processes. This study provides a comprehensive insight into the chemical composition and sensory quality of different Liupao tea fermentations.


Assuntos
Catequina , Chá , Fermentação , Chá/química , Cromatografia Líquida de Alta Pressão , Metabolômica , Catequina/análise , Ácido Gálico/química , Metaboloma
13.
Food Chem ; 404(Pt A): 134504, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36228474

RESUMO

Non-enzymatic browning is a severe problem in juice industry. Here, polyphenol mediated non-enzymatic browning and its inhibition in apple juice were investigated. Epicatechin (R = -0.83), catechin (CAT, R = -0.79), chlorogenic acid (CGA, R = 0.65) and caffeic acid (CAF, R = 0.65) were strongly correlated with browning. CAT and chlorogenic acid quinone (CGAQ) decreased during storage with the fastest CAT degradation rate (kCGA-enriched = 1.97 × 10-3 mg·L-1·h-1 and kCAT-enriched = 2.09 × 10-3 mg·L-1·h-1) at the initial stage, but CGA and catechin quinone (CATQ) hardly changed. It was possible that CGAQ oxidized CAT at initial stage, leading to the generation of CATQ but less browning. Then the formed CATQ reacted with CAT through the complex reactions, leading to the accumulation of yellow polymers, which might explain why browning increased faster during the secondary and tertiary stages. In addition, glutathione could effectively inhibit browning compared to ascorbic acid and oxygen blocking methods.


Assuntos
Catequina , Malus , Polifenóis , Ácido Clorogênico , Quinonas
14.
Food Chem ; 404(Pt A): 134587, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36257264

RESUMO

With the concern of rapid retrogradation of chestnut starch, the effect of heat-moisture treatment (HMT) with flavonoids on the retrogradation of chestnut starch was studied. The retrogradation of starch could be inhibited by HMT combined with flavonoid addition up to 65.88%. Flavonoids with different structures showed significant differences in retarding retrogradation, which followed the order of epicatechin>epicatechin gallate>oligmeric proanthocyanidins. Structural analysis, infrared spectra and theoretical calculations showed that hydrogen bond interactions between starch and flavonoids retarded starch retrogradation by inhibiting the aggregation of starch molecules to form crystalline and aggregation structures. The retarding effect of flavonoids was related to their steric hindrance, flexibility and phenolic hydroxyl number. Epicatechin with minor steric hindrance and more flexibility favored its hydrogen bond interactions with starch, leading to the best retardation effect of starch retrogradation. This study would provide a theoretical and experimental basis for creating high-quality chestnut products.


Assuntos
Catequina , Amido , Amido/química , Temperatura Alta , Flavonoides , Ligação de Hidrogênio
15.
Gene ; 849: 146907, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36174904

RESUMO

The flavanol (-)-epicatechin has exercise-mimetic properties. Besides, several miRNAs play a role in modulating the adaptation of the muscle to different training protocols. However, notwithstanding all information, few studies aimed to determine if (-)-epicatechin can modify the expression of miRNAs related to skeletal muscle development and regeneration. Mice were treated for fifteen days by oral gavage with the flavanol (-)-epicatechin. After treatment, the quadriceps of the mice was dissected, and total RNA was extracted. The expression level of miR-133, -204, -206, -223, -486, and -491 was analyzed by qRT-PCR. We also used bioinformatic analysis to predict the participation of these miRNAs in different skeletal muscle signal transduction pathways. Additionally, we analyzed the level of the myogenic proteins MyoD and myogenin by Western blot and measured the cross-sectional area of muscle fibers stained with E&H. (-)-Epicatechin upregulated the expression of miR-133, -204, -206, -223, and -491 significantly, which was associated with an increase in the level of the myogenic proteins MyoD and Myogenin and an augment in the fiber size. The bioinformatics analysis showed that the studied miRNAs might participate in different signal transduction pathways related to muscle development and adaptation. Our results showed that (-)-epicatechin upregulated miRNAs that participate in skeletal exercise muscle adaptation, induced muscle hypertrophy, and increased the level of myogenic proteins MyoD and MyoG.


Assuntos
Catequina , MicroRNAs , Camundongos , Animais , Miogenina/genética , Miogenina/metabolismo , Proteína MyoD/genética , Proteína MyoD/metabolismo , Catequina/farmacologia , Músculo Esquelético/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Diferenciação Celular
16.
Food Chem ; 403: 134456, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36358080

RESUMO

The inhibitory effects of chitooligosaccharide-epigallocatechin gallate (COS-EGCG) conjugate in comparison with COS, EGCG, and acarbose on α-amylase were studied. The half-maximum inhibitory concentration (IC50) of COS-EGCG conjugate against α-amylase was 4.62 mg/mL, which was lower than other samples expect acarbose (IC50 = 0.48 mg/mL) (p < 0.05). COS-EGCG conjugate showed the mixed-type inhibition kinetic and had Kic of 1.516 mg/mL, which was less than those of COS (Kic = 4.572 mg/mL) and EGCG (Kic = 2.248 mg/mL) (p < 0.05). COS-EGCG conjugate linked with amino acids of α-amylase via hydrogen bonding, van der Waals and hydrophobic interactions as elucidated by molecular docking. Interaction between COS-EGCG conjugate and α-amylase was achieved with the binding affinity of -14.30 kcal/mol (p < 0.05). COS-EGCG conjugate spontaneously alterated the micro-environment around the active site as shown by fluorescence quenching. Therefore, mechanism for retarding digestibility of starch by COS-EGCG conjugate was elucidated. COS-EGCG conjugate could be incorporated as functional ingredient in various foods to possess low-glycaemic index.


Assuntos
Catequina , Quitosana , Acarbose , Simulação de Acoplamento Molecular , Catequina/química , alfa-Amilases/metabolismo , Relação Estrutura-Atividade
17.
Talanta ; 252: 123853, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35998448

RESUMO

In this work, 2-methylimidazole (MI) was doped into the Bpy-Cu nanozyme as a second ligand to form a novel laccase-mimicking enzyme (MI-Bpy-Cu). By comparison, MI-Bpy-Cu nanozyme was identified to have excellent laccase-mimicking activity, high stability and catalytic kinetic properties. It may be that the incorporation of 2-methylimidazole helped the nanozymes to build a structure closer to natural laccase and accelerate the electron transfer rate, thereby achieving the purpose of enhancing the activity. Furthermore, we observed that MI-Bpy-Cu nanozymes could oxidize the colorless (+)-Catechin to generate a yellow radical product, and a novel colorimetric sensing strategy for (+)-Catechin was successfully developed. The method had excellent selectivity and anti-interference properties, and also had good application in the analysis of (+)-Catechin in dairy products.


Assuntos
Catequina , Lacase , Lacase/química , Catequina/química , Catálise , Colorimetria/métodos , Laticínios
18.
J Sci Food Agric ; 103(1): 213-220, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35871448

RESUMO

BACKGROUND: Roasting plays an important role in the formation of flavor of roasted green tea; however, the changes in chemicals during this process have not been systematically studied until now. To reveal the dynamic changes in chemicals in green tea during roasting, non-targeted metabolomics, coupled with chemometrics, was employed. RESULTS: A total of 101 non-volatile metabolites were identified in tea samples, and 29 metabolites were identified as characteristic metabolites of roasting. A significant increase in catechins and their derivatives, organic acids, and flavonoid glycosides was observed, while the content of some amino acids and their derivatives decreased over 50% during roasting. The content of theanine glucoside increased dramatically (by 21.23-fold at the roasting stage), and Maillard-derived compounds also increased to varying degrees. CONCLUSION: Glycosylation, oxidative polymerization, and pyrolysis were important reactions responsible for the formation and transformation of flavor compounds in roasted green tea during roasting. © 2022 Society of Chemical Industry.


Assuntos
Catequina , Chá , Chá/química , Temperatura Alta , Metabolômica
19.
Food Res Int ; 162(Pt A): 111911, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36461180

RESUMO

This study investigated the formation of polycyclic aromatic hydrocarbons (PAHs) in a mutton intramuscular fat model system containing epicatechin under various reaction conditions using multivariate statistical analysis, and established the optimal equations for PAHs prediction. Results indicated that at 100-180 °C for 10-60 min, epicatechin inhibited the formation of naphthalene, acenaphthylene, phenanthrene, anthracene, benz[a]anthracene and benzo[g,h,i]perylene by 10-37 %, 11-32 %, 9-100 %, 27-56 %, 100 % and 6-18 %, respectively. Polynomial equation third-order model with R2 at 0.87-0.98 and R2 at 0.80-0.95 well fitted for the formation of PAHs under various temperatures and times, respectively. The correlation coefficients of calibration set (R2c) and validation set (R2v) were 0.92 and 0.81 for naphthalene, 0.84 and 0.84 for acenaphthylene, 0.99 and 0.98 for phenanthrene, 0.97 and 0.95 for anthracene, 0.91 and 0.80 for benzo[g,h,i]perylene, respectively, which suggested good mathematical models for the PAHs formation rules. These results provide theoretical support to develop technologies for PAHs real-time monitoring during roasted mutton processing.


Assuntos
Catequina , Perileno , Fenantrenos , Hidrocarbonetos Policíclicos Aromáticos , Naftalenos , Antracenos
20.
Aging (Albany NY) ; 14(21): 8633-8644, 2022 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-36375471

RESUMO

Increased levels of oxidative stress are major factors that drive the process of post-ovulatory oocyte aging. Epigallocatechin-3-gallate (EGCG), which accounts for up to 50% of the catechins, possesses versatile biological functions, including preventing or treating diabetes, cancer, and heart diseases. The aim of this study was to explore whether EGCG can delay porcine oocyte aging by preventing oxidative stress. Metaphase II (MII) oocytes were cultured for 48 h with different concentrations of EGCG (0-100 µM) in vitro as a post-ovulatory aging model. An optimal concentration of 5 µM EGCG maintained oocyte morphology and developmental competence during aging. The oocytes were randomly divided into five groups: fresh, 24 h control, 24 h EGCG, 48 h control, and 48 h EGCG. The results suggest that EGCG significantly prevents aging-induced oxidative stress, glutathione (GSH) reduction, apoptosis, and autophagy. Moreover, mitochondria DNA copy number was decreased, and the number of active mitochondria and adenosine triphosphate (ATP) levels significantly increased by supplementation with EGCG. Thus, EGCG has a preventive role against aging in porcine post-ovulatory oocytes due to its ability to inhibit oxidative stress and promote mitochondrial biogenesis.


Assuntos
Catequina , Oócitos , Animais , Envelhecimento , Catequina/farmacologia , Glutationa , Estresse Oxidativo , Suínos
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