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1.
Food Chem ; 335: 127566, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745839

RESUMO

In this work, we developed an optical colorimetric sensor array for the discrimination of Chinese teas. The sensor array was carefully designed based on tea polyphenol induced indicators displacement assay (IDA), using phenylboronic acids with different substituents as the receptors to polyphenols. The accurate identification for polyphenols with different species or concentrations proved the potential of the sensor array. The sensor array successfully distinguished tea samples within different categories, grades and origins, coupling with PLS-DA. This work offered an efficient and rapid method to distinguish teas and tea-related products. Besides, the assay is supposed to be suitable for the identification of other polyphenol-related natural products.


Assuntos
Camellia sinensis/química , Colorimetria/instrumentação , Polifenóis/análise , Qualidade dos Alimentos , Limite de Detecção
2.
J Food Sci ; 85(9): 2933-2942, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32794200

RESUMO

Fuzhuan Brick-Tea is a postfermented product with the hypoglycemic effect, which is prepared from the leaves of Camellia sinensis var. sinensis. However, the material basis associated with the hypoglycemic effect was not clear. The present research was designed to explore the hypoglycemic effect of extract/fractions from Fuzhuan Brick-Tea in streptozotocin-induced type II diabetic mice. Then an ultra-high pressure liquid chromatography along with quadrupole time of flight mass spectrometry was used to analyze the phytochemicals in Fuzhuan Brick-Tea fractions. As a result, the hypoglycemic and hypolipidemic effects were evidently observed from the serum biochemical indexes and liver pathological examination in type II diabetic mice. In addition, there were total of 20 major components including eight lysophosphatidylcholines (Lyso-PCs), five fatty acids, and seven novel theophylline derivatives tentatively identified in the active fraction from water extract. Therefore, these components were assumed to contribute partly to the hypoglycemic effect of Fuzhuan Brick-Tea. These findings also give the evidence that the Lyso-PCs, fatty acids, and novel theophylline derivatives in Fuzhuan Brick-Tea may provide benefits in ameliorating disorders of glucose and lipid metabolism. PRACTICAL APPLICATION: This study suggests that the Lyso-PCs, fatty acids, and novel theophylline derivatives in Fuzhuan Brick-Tea may provide benefits in ameliorating disorders of glucose and lipid metabolism. It can be taken as a beneficial diet additive or nutraceutical.


Assuntos
Camellia sinensis/química , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Extratos Vegetais/administração & dosagem , Animais , Cromatografia Líquida de Alta Pressão , Diabetes Mellitus Experimental/metabolismo , Ácidos Graxos/metabolismo , Fermentação , Humanos , Hipoglicemiantes/química , Metabolismo dos Lipídeos , Fígado/metabolismo , Masculino , Camundongos , Extratos Vegetais/química , Folhas de Planta/química , Estreptozocina , Espectrometria de Massas em Tandem/métodos , Chá/química
3.
Food Chem ; 333: 127499, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673957

RESUMO

This study was to examine the formation of advanced glycation end-products (AGEs) in black tea during drying process at 90, 120, and 150 °C for 1 h. Nine AGEs including Nɛ-(carboxyethyl)-l-lysine (CEL), Nɛ-(carboxymethyl)-l-lysine (CML), three isomers of methylglyoxal-hydroimidazolones (MG-Hs), three isomers of glyoxal-hydroimidazolones (GO-Hs), and argpyrimidine were quantified by using HPLC-MS/MS with isotope-labelled internal standard. Results showed that each AGE during the drying process of 150 °C was significantly higher (p < 0.05) than at 90 and 120 °C, and argpyrimidine was only found in the treatment of 150 °C. MG-H1/3 was first quantified as the major AGE during drying at 120-150 °C, the content respectively reached to (39.66 ± 2.61) µg/g and (58.88 ± 1.76) µg/g after 1 h drying, where CML content only had (19.86 ± 1.02) µg/g and (23.71 ± 1.40) µg/g. This study indicated that arginine derived-AGEs are the key components of black tea AGEs.


Assuntos
Camellia sinensis/química , Produtos Finais de Glicação Avançada/análise , Imidazóis/química , Lisina/análogos & derivados , Extratos Vegetais/química , Aldeído Pirúvico/química , Cromatografia Líquida de Alta Pressão , Dessecação , Manipulação de Alimentos , Humanos , Isomerismo , Lisina/química , Folhas de Planta/química , Espectrometria de Massas em Tandem , Chá
4.
Food Chem ; 332: 127412, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32623128

RESUMO

In this study, metabolomics and proteomics were employed to investigate the change mechanism of nonvolatile compounds during white tea processing. A total of 99 nonvolatile compounds were identified, among which the contents of 13 free amino acids, caffeine, theaflavins, 7 nucleosides and nucleotides, and 5 flavone glycosides increased significantly, while the contents of theanine, catechins, theasinesins, 3 proanthocyanidins, and phenolic acids decreased significantly during the withering period. The results of proteomics indicated that the degradation of proteins accounted for the increase in free amino acid levels; the weakened biosynthesis, in addition to oxidation, also contributed to the decrease in flavonoid levels; the degradation of ribonucleic acids contributed to the increase in nucleoside and nucleotide levels during the withering period. In addition, the drying process was found to slightly promote the formation of white tea taste. Our study provides a novel characterization of white tea taste formation during processing.


Assuntos
Camellia sinensis/química , Metabolômica/métodos , Chá/química , Alcaloides/análise , Alcaloides/metabolismo , Camellia sinensis/metabolismo , Catecóis/análise , Catecóis/metabolismo , Flavonoides/análise , Flavonoides/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Proteômica , Chá/metabolismo
5.
J Food Sci ; 85(7): 2060-2068, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32579746

RESUMO

The aim of this study was the development of innovative candies formulations accordant with the present trends in the confectionery industry. Steviol glycosides, sorbitol, and agave syrup were used as sucrose alternatives, while agar and pectin were included instead of gelatin for the formulation of vegan candies. Additionally, white tea extract was used as a candy base and source of bioactive compounds. Bioactive quality (total phenolic content, antioxidant capacity, epigallocatechin gallate, and caffeine content) and physicochemical (dry matter, springiness, hardness, color) parameters of candies were monitored during 4 months of storage at 4 and 22 °C. Pectin candies with the highest content of dry matter (79.8%) showed the longest shelf life, while those with agar (52.0% and 66.2%) were the most susceptible to spoilage. Candies prepared with agar were less hard (0.4 and 0.6 N) and with less elastic texture (1.5 and 3.4 mm) and showed the highest stability of physicochemical parameters during storage, while those with pectin were also less hard (0.5 N) but with more elastic texture (10.7 mm) than gelatin candies (3.6 and 4.4 mm; 2.4 and 4.1 N). Although gelatin samples were characterized with the greatest bioactive quality parameters immediately after production, they showed a higher instability of the same parameters during storage compared to the agar and pectin candies. PRACTICAL APPLICATION: According to the consumers' demands for healthier confectionery products, formulations of candies with sucrose alternatives, non-animal hydrocolloids, and natural bioactive compounds were developed. Giving a deeper insight into their physicochemical and bioactive properties, this paper could contribute to confectionery industry in development and optimization of formulations in order to obtain candies with desirable and attractive properties.


Assuntos
Camellia sinensis/química , Doces/análise , Aditivos Alimentares/análise , Manipulação de Alimentos/métodos , Extratos Vegetais/análise , Antioxidantes/análise , Catequina/análogos & derivados , Catequina/análise , Armazenamento de Alimentos , Gelatina/química
6.
J Food Sci ; 85(6): 1629-1634, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32468625

RESUMO

Tea, a popular aromatic infusion and food supplement, prepared from Camellia sinensis (L.) Kuntze leaves, is often subjected to adulteration with various undeclared inorganic and plant-derived materials. Cashew (Anacardium occidentale L.) nut husk is one of the most common plant tea adulterants. To date, there are limited DNA-based technologies for tea authentication and quantitative detection of adulterants. Herein, we used a universal plant DNA barcoding marker coupled with High Resolution Melting (Bar-HRM) analysis to authenticate tea products from cashew ground nut. Additionally, cashew-specific markers coupled with HRM technology were used to detect and quantify adulteration of tea with cashew DNA. This methodology can reliably detect admixtures as low as 1% v/v cashew in commercial tea products. Overall, our results demonstrate that the HRM technology is a strong molecular approach in tea authentication, capable of detecting very low adulterations in DNA admixtures. PRACTICAL APPLICATION: In this study, we established the use of high-resolution DNA-based technologies for the detection of cashew adulteration in tea, even in very low quantities. The technology could be applied to a greater range of plant-based tea adulterants. This work is expected to facilitate the traceability and authenticity of tea products and form the basis for the development of strategies against fraudulent practices.


Assuntos
Anacardium/genética , Camellia sinensis/genética , Contaminação de Alimentos/análise , Chá/química , Anacardium/química , Camellia sinensis/química , Código de Barras de DNA Taxonômico/métodos , DNA de Plantas/química , DNA de Plantas/genética , Contaminação de Alimentos/economia , Marcadores Genéticos , Chá/economia , Temperatura de Transição
7.
Food Chem ; 326: 126928, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32408000

RESUMO

Maximum residue limits (MRLs) for pesticides have been established in teas for quality control and protection of consumer health in many countries and regions, including Europe. It is, however, challenging to quantify multi-pesticide residues at low concentrations in complex matrices, such as tea. In this study, highly sensitive, efficient, and rugged analytical methods were adapted for simultaneous determination of 400 pesticide residues in green tea products using ultra performance liquid and gas chromatography coupled to tandem mass spectroscopy (UPLC-MS/MS and GC-MS/MS). Matrix effects were minimized by combining QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction and mixed-mode SPE clean-up with different sorbents in sample preparation. A C18 SPE cartridge paired with SPE GCB/PSA proved to be the most effective clean-up method and enabled 225 pesticide residues to be quantified, based on solvent calibration curves (154 residues using UPLC-MS/MS and 71 residues using GC-MS/MS). The analytical methods were validated fully in accordance with the SANTE/11945/2015. LOQs for most pesticides (386/400 or 96.5%) were below 10 µg/kg, i.e., less than the EU MRL (5-70 mg/kg). Thus, these approaches can be applied for routine analysis of multi-pesticide residues in green tea.


Assuntos
Camellia sinensis/química , Cromatografia Gasosa/métodos , Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Europa (Continente) , Contaminação de Alimentos/análise , Folhas de Planta/química , Chá/química
8.
Food Chem ; 327: 127092, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32450485

RESUMO

Black and green tea are popular owing to their unique flavors and health benefits. However, these teas can be contaminated with anthraquinones, which are associated with health risks in humans. Levels of 9,10-anthraquinone were determined at each step of the manufacturing process for green and black tea using gas chromatography-tandem mass spectrometry. For green tea, anthraquinone was present beginning at the withering process and increased in concentration until the first drying step. Additionally, for black tea, the first drying step resulted in a significant increase in anthraquinone content, whereas the concentration decreased during the final drying step. For black tea, anthraquinone was also detected during withering, although the concentration continued to increase throughout the entire procedure, particularly during drying. Therefore, it can be suggested that the presence of anthraquinone in these teas was influenced by the smoke emitted by the wood fires used to drive the processing machinery.


Assuntos
Antraquinonas/isolamento & purificação , Camellia sinensis/química , Chá/química , Dessecação , Indonésia , Folhas de Planta/química
9.
J Food Sci ; 85(6): 1948-1955, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32424941

RESUMO

Polysaccharides have various health-promoting functions. However, dietary polysaccharides cannot be digested by the human alimentary tract, thus the gut is the most important location where polysaccharides play their role. The effect of polysaccharides from tea (Camellia sinensis L.) flower (TFPS) on intestinal health was investigated in the present study. TFPS with the molecular weight of 1,316.29 kDa was prepared, and twenty 6-week-old BALB/c male mice were randomly allotted to a chow diet (normal control group, NC group) or with 200 mg/kg (body weight)/day of TFPS for 13 weeks (n = 10 each). Histomorphology observation of jejunum and colons showed that TFPS maintained the adequate gut barrier. qPCR analysis revealed that the expression of colonic tight junction proteins of claudin1 (1.29 ± 0.15 compared with 1.00 ± 0.13, P < 0.05) and claudin5 (2.91 ± 0.44 compared with 1.00 ± 0.27, P < 0.01) at mRNA level with a significant difference between TFPS supplement or not, while the expression of TLR4 and TNF-α mRNA was not changed statistically. 16S rDNA amplicons sequencing was applied to measure the compositions of gut microbiota from feces of mice. TFPS treatment exhibited similar relative abundances in Bacteroidetes and Firmicutes; however, it decreased the relative abundance of Akkermansia and increased that of Lactobacillus compared with the NC group. The contents of short-chain fatty acids after TFPS supplementation, both in cecal contents and feces, were significantly higher than those of the NC group. Besides, TFPS significantly increased IgA production. These results suggest that TFPS is beneficial to intestinal health and can improve intestinal adaptive immune tolerance. PRACTICAL APPLICATION: Dietary polysaccharides improve human intestinal health. Understanding the effect of TFPS, safe and healthy food components, on gut health increases the likelihood that TFPS will be developed as a functional food.


Assuntos
Camellia sinensis/metabolismo , Microbioma Gastrointestinal , Preparações de Plantas/metabolismo , Polissacarídeos/metabolismo , Animais , Camellia sinensis/química , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Flores/química , Intestinos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Preparações de Plantas/química , Polissacarídeos/química , Chá/metabolismo
10.
Braz J Med Biol Res ; 53(5): e9303, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348424

RESUMO

The control of dyslipidemia using plants is an important subject of studies since it has numerous benefits in cardiovascular protection. The objective of this study was to evaluate the effect of three Camellia sinensis L. teas (green, red, and white) on left ventricular hypertrophy and insulin resistance in low-density lipoprotein receptor knockout (LDLr-/-) mice fed a high-fat diet. The LDLr-/- mice were divided into four experimental groups: Group C: standard feed; Group CT: standard feed and three teas, Group HL: high-fat feed; HLT Group: high-fat feed and three teas. The three types of tea (green, red, and white) originated from different processing of the Camellia sinensis L. plant, and were administered associated once a day at a dose of 25 mg/kg by gavage for 60 days. The teas partially prevented hyperlipidemia, the decrease of the serum levels of high-density lipoproteins (HDL), insulin resistance, and increased C-reactive protein (CRP) levels, and completely prevented left ventricular hypertrophy in LDLr -/- mice of the HLT group. In conclusion, the three Camellia sinensis L. teas used to control genetic dyslipidemia associated with a high-fat diet can be used as an auxiliary treatment associated with the control of lipid intake, thus promoting cardiac protection against hyperlipidemia.


Assuntos
Antioxidantes/administração & dosagem , Camellia sinensis/química , Dislipidemias/tratamento farmacológico , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Resistência à Insulina , Extratos Vegetais/administração & dosagem , Chá , Animais , Antioxidantes/isolamento & purificação , Masculino , Camundongos
11.
J Food Sci ; 85(5): 1450-1461, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32249418

RESUMO

Bound phenolic compounds have rarely been reported in vegetable oils and this may be due to little research about the extraction. Deep eutectic solvents (DESs), recently applied in the extraction of phenolic compounds as alternatives to organic solvents, were adopted in the extraction of free and bound phenolic compounds from tea seed oil in this work. First, the phenolic compounds were analyzed by ultra-high-performance liquid chromatography with quadrupole-time-of-flight and triple-quadrupole tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) for characterization and UHPLC-QqQ-MS/MS for quantification and 25 phenolic compounds were found to exist in both free and bound forms. Then, DESs were screened for extraction of free and bound phenolic compounds from tea seed oil as the pretreatment for analysis and the results showed that hydrogen bond donors (HBDs) and temperature significantly affected the extraction efficiency of DESs. Finally, free phenolic compounds (83.91 µg/g) and bound phenolic compounds (25.71 µg/g), extracted by the DES with glycerol as HBD at 50 °C, were 51.0% and 93.2% higher than those extracted by methanol/water (60%, v/v), respectively. This work not only advanced the basic data of phenolic compounds in tea seed oil but also explored an efficient extraction method for scientific analysis of free and bound phenolic compounds.


Assuntos
Camellia sinensis/química , Fenóis/química , Fenóis/isolamento & purificação , Óleos Vegetais/química , Sementes/química , Cromatografia Líquida de Alta Pressão , Ligação de Hidrogênio , Óleos Vegetais/isolamento & purificação , Solventes/química , Espectrometria de Massas em Tandem
12.
Arch Biochem Biophys ; 687: 108369, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32335047

RESUMO

A neutral tea polysaccharide (TPSN) was isolated from green tea. Gas chromatography analysis showed that TPSN was composed of d-glucose, l-arabinose and d-galactose residues at a molar ratio of 90.0: 9.1: 0.9. The weight-averaged molecular weight of TPSN was determined as about 2.0 × 105 g mol-1 using static light scattering analysis. The result of nuclear magnetic resonance (NMR) spectroscopy indicated that TPSN and water-soluble starch had similar structures. TPSN exhibited inhibitory activity towards α-amylase through the noncompetitive inhibition mechanism, but the tertiary structure of α-amylase related to enzymatic activity, analyzed using circular dichroism spectroscopy, was not affected by TPSN. Meanwhile, TPSN exhibited hydrolysis properties catalyzed by α-amylase. Molecular docking analysis revealed that the various behaviors of TPSN to α-amylase could be attributed to that the different chain segments of TPSN combined with different amino acid residues of α-amylase.


Assuntos
Inibidores Enzimáticos/química , Polissacarídeos/química , Chá/química , alfa-Amilases/antagonistas & inibidores , Animais , Camellia sinensis/química , Ensaios Enzimáticos , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/metabolismo , Hidrólise , Cinética , Simulação de Acoplamento Molecular , Peso Molecular , Polissacarídeos/isolamento & purificação , Polissacarídeos/metabolismo , Ligação Proteica , Suínos , alfa-Amilases/metabolismo
13.
Poult Sci ; 99(4): 1956-1966, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32241476

RESUMO

The present study was to evaluate antioxidative effect of tea extract granule (TEG) on oxidative stress induced by cyclophosphamide (Cy) in chickens. In experiment 1, chickens were randomly divided into 5 groups with 10 birds in each. Groups 3 to 5 were orally administered TEG in drinking water for 7 D at doses of 20, 40, and 80 mg/kg body weight, respectively. After that, groups 2 to 5 received intramuscular injection of Cy (100 mg/kg BW) for 3 D. Group 1 was not treated as a control. In experiment 2, chickens were grouped in the same way as in experiment 1. Groups 2 to 5 received intramuscular injection of Cy (100 mg/kg BW) for 3 D. After that, groups 3 to 5 were orally administered TEG in drinking water for 7 D at doses of 20, 40, and 80 mg/kg BW, respectively. Results showed that Cy injection induced significantly decreased body weight and oxidative stress. Oral administration of TEG before or after Cy injection increased body weight, the thymus, bursa, and spleen indices, total antioxidant capacity, and the levels of glutathione; elevated the activity of superoxide dismutase, catalase, and glutathione peroxidase; as well as decreased the protein carbonyl content, lipid peroxide, and malondialdehyde. In addition, TEG administration reduced intracellular reactive oxygen species. Therefore, TEG could be a promising agent against oxidative stress in the poultry industry.


Assuntos
Antioxidantes/farmacologia , Camellia sinensis/química , Galinhas/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Administração Oral , Animais , Peso Corporal , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Masculino , Oxirredução , Extratos Vegetais/química , Espécies Reativas de Oxigênio/metabolismo , Organismos Livres de Patógenos Específicos
14.
Food Chem ; 317: 126428, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113139

RESUMO

During manufacturing processes and in the storage period of tea, amino acids may undergo enantiomeric isomerization, converting their l- to d-forms. To examine the hypothesis, a method was developed for the analysis of the enantiomers in tea leaves. After enriched by ion-exchange solid-phase extraction, the enantiomeric pairs were separated by a chiral high performance liquid chromatography (HPLC) and subsequently detected and identified by using a high resolution quadrupole time-of-flight mass spectrometry (QTOF MS). Only l-forms of amino acids were found in fresh tea leaves. A total of 11 d-amino acids were found in 19 tea samples, ranging from trace amount to 43 µg/g. The results indicated that the enantioisomerization of amino acids occurred in post-harvest tea leaves, and affected by process conditions and storage time.


Assuntos
Aminoácidos/análise , Aminoácidos/química , Camellia sinensis/química , Análise de Alimentos/métodos , Folhas de Planta/química , Chá/química , Cromatografia Líquida de Alta Pressão/métodos , Armazenamento de Alimentos , Espectrometria de Massas , Sensibilidade e Especificidade , Extração em Fase Sólida , Estereoisomerismo
15.
Cochrane Database Syst Rev ; 3: CD005004, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32118296

RESUMO

BACKGROUND: This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects. OBJECTIVES: To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes. SEARCH METHODS: We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies. SELECTION CRITERIA: We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both. DATA COLLECTION AND ANALYSIS: Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type. MAIN RESULTS: In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies. AUTHORS' CONCLUSIONS: Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.


Assuntos
Camellia sinensis , Neoplasias/prevenção & controle , Fitoterapia/métodos , Extratos Vegetais/uso terapêutico , Chá , Neoplasias da Mama/prevenção & controle , Camellia sinensis/química , Estudos de Casos e Controles , Feminino , Flavonoides/farmacologia , Neoplasias Gastrointestinais/epidemiologia , Neoplasias Gastrointestinais/prevenção & controle , Humanos , Incidência , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/prevenção & controle , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/prevenção & controle , Masculino , Neoplasias Bucais/epidemiologia , Neoplasias Bucais/prevenção & controle , Neoplasias/epidemiologia , Neoplasias/mortalidade , Fenóis/farmacologia , Extratos Vegetais/efeitos adversos , Polifenóis , Ensaios Clínicos Controlados Aleatórios como Assunto , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/prevenção & controle , Chá/efeitos adversos , Neoplasias Urogenitais/epidemiologia , Neoplasias Urogenitais/prevenção & controle
16.
Enzyme Microb Technol ; 135: 109496, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32146939

RESUMO

Catechins in green tea possess various health benefits. Enzymatic treatment improves physiological activities by inducing bioconversion of catechins. Here, we investigated the effect of green tea infusion (GT) after tannase treatment, which transforms (-)-epigallocatechin gallate (EGCG) to gallic acid (GA) and (-)-epigallocatechin (EGC), on adipocyte differentiation and mature adipocyte metabolism. The optimal conditions for tannase-mediated improvement in GA and EGC yields in GT were investigated using response surface methodology. Yields of GA and EGC were 43-fold (0.43 mg/mL) and 1.66-fold higher (1.11 mg/mL), respectively, compared to GT without tannase treatment. The optimal reaction conditions for tannase-mediated biotransformation were observed on 0.54 mg mL-1 of tannase, reaction time (86.79 min), and reaction temperature at 22.59 °C. GT and tannase-treated GT (TANs) upregulated adiponectin, uncoupling protein 1, adipose triglyceride lipase, and hormone-sensitive lipase gene expression in differentiated 3T3-L1 adipocytes, with TAN inducing better effects than GT, which implies that tannase treatment improved the beneficial effect of GT on adipocyte metabolism. Thus, tannase-mediated bio-transformation is an attractive candidate for preparing GT with enhanced anti-obesity properties.


Assuntos
Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Hidrolases de Éster Carboxílico/química , Catequina/análogos & derivados , Proteínas Fúngicas/química , Extratos Vegetais/química , Adipócitos/citologia , Adiponectina/genética , Adiponectina/metabolismo , Animais , Aspergillus/enzimologia , Biocatálise , Camellia sinensis/química , Catequina/química , Catequina/farmacologia , Diferenciação Celular , Manipulação de Alimentos , Ácido Gálico/química , Ácido Gálico/farmacologia , Camundongos , Células NIH 3T3 , Extratos Vegetais/farmacologia , Folhas de Planta/química , Chá/química , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
17.
J Food Sci ; 85(4): 1105-1113, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32175596

RESUMO

The purpose of this study was to prepare and characterize inclusion complexes between tea polyphenol (TP) and hydroxypropyl-ß-cyclodextrin (HP-ß-CD), and to evaluate their antioxidant properties. Freeze-drying was used to prepare the inclusion complex of TP/HP-ß-CD at different component ratios (1:0.5, 1:1, and 1:2). The supermolecular structure of the TP/HP-ß-CD complex was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Molecular docking was used to simulate the positions and interactions of the binding sites of TP/HP-ß-CD inclusion complexes and target protein receptors. In addition, the effects of TP/HP-ß-CD inclusion complexes on myofibrillar protein (MP) from lamb tripe were observed under oxidative conditions. Results showed that TP was encapsulated in the cavity of HP-ß-CD to form an optimal complex with 1:2 molar ratio of stoichiometry, while the FTIR, TGA, and SEM studies also support the inclusion process. Molecular modeling results were systematically analyzed to determine the stability of inclusion complexes and protein. Furthermore, the addition of an appropriate concentration (5 to 105 µmol/g) of TP/HP-ß-CD inclusion complex decreased the carbonyl content, hydrophobicity, and protein aggregation of MP from lamb tripe, whereas it increased the sulfhydryl content. This improved antioxidant activity and bioavailability of the inclusion complexes will be beneficial for its potential applications in food. PRACTICAL APPLICATION: Tea polyphenol was an antioxidant with potential for the field of food. In this study, the unstable properties of tea polyphenols were evaluated and were improved by inclusion of HP-ß-cyclodextrin. The binding mode of the inclusion complex with protein was revealed via the molecular docking method, and the application of inclusion complex to control protein oxidation was studied. Results showed that the inclusion complex could effectively inhibit protein oxidation, which can provide a reference for the application of polyphenols in meat products and the improvement of protein properties.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/química , Antioxidantes/química , Extratos Vegetais/química , Polifenóis/química , Animais , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Camellia sinensis/química , Liofilização , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Simulação de Acoplamento Molecular , Ovinos , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Environ Geochem Health ; 42(9): 2853-2863, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32166521

RESUMO

The total mean ∑[Formula: see text] in samples were from 75.3 to 387.0 ng/g dry weight (d.w) and showed high value in black dry tea, followed by herbal, oolong, and green tea. The mean ∑[Formula: see text] (a combination of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) values were 54.3 ng/g, 16.4 ng/g, 14.2 ng/g, and 6.6 ng/g for black, herbal, green, and oolong teas, respectively. Concentration for benzo[a]pyrene (BaP) was from 0.4 to 35.8 ng/g, and the BaP equivalent concentration values ranged from 0.3 to 48.1 ng/g. There was only 1 black tea sample that BaP concentration exceeded the maximum level according to European Union (EU) standards. Tea samples marketed in Vietnam showed insignificant difference with the samples from other origins by same analytical method. Black teas showed high PAHs contents in dry tea samples but the released percentage of sum of PAHs from tea-to-tea infusion was lower than that in other tea type samples. The released percentages of PAH4 from tea-to-tea infusion were 40.7, 15.4, and 1.9 for green, herbal, and black tea. High temperature in black tea manufacturing processes might reduce essential oil content in tea that might effect on the PAHs partially release into the infusion. Indeed, based on EU regulations, we may conclude that tea consumers are safe in risk of exposure to PAHs obtained from teas.


Assuntos
Exposição Dietética/análise , Contaminação de Alimentos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Chá/química , Benzo(a)pireno/análise , Camellia sinensis/química , Crisenos/análise , Exposição Dietética/efeitos adversos , Fluorenos/análise , Humanos , Folhas de Planta/química , Medição de Risco/métodos , Chás de Ervas/análise , Vietnã
19.
BMC Complement Med Ther ; 20(1): 47, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32046706

RESUMO

BACKGROUND: The aim of this study was to investigate the effect of tannase-converted green tea extract with a high (-)-epicatechin (EC), (-)-epigallocatechin (EGC), and gallic acid (GA) content on myotube density and fusion in normal and oxidative stress-induced C2C12 skeletal muscle cells. Although the use of green tea extract is considered beneficial, cellular and molecular mechanisms of action of tannase-converted green tea extracts that are used as potential muscle growth materials have not been thoroughly studied. METHODS: This study used histological analysis and molecular biology techniques, and compared the results with those for AMPK activator 5-aminoimidazole-4-carboxamide-1-ß-D-ribonucleoside (AICAR) and green tea extracts. RESULTS: The myotube density of normal and oxidative stress-induced C2C12 cells was significantly higher in the tannase-converted green tea extract-treated group than that observed in the other groups (normal cells: P < 0.01; oxidative stress-induced cells: P < 0.05). In addition, tannase-converted green tea extract and green tea extract treatments significantly upregulated the genetic expression of myogenin, Myf5, and MyoD (P < 0.05). The levels of AMP-activated protein kinase-α (AMPKα) and muscle RING-finger protein-1 (MuRF-1) in the tannase-converted green tea extract group were higher than those in the AICAR and green tea extract groups (P < 0.05). CONCLUSIONS: Taken together, our findings describe that the high levels of EC, EGC, and GA in the tannase-converted green tea extract are attributable to the morphological changes in C2C12 cells and intercellular signaling pathways. Therefore, tannase-converted green tea extract can be used in the treatment of sarcopenia.


Assuntos
Catequina/farmacologia , Desenvolvimento Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Chá/química , Animais , Antioxidantes/metabolismo , Camellia sinensis/química , Hidrolases de Éster Carboxílico/metabolismo , Linhagem Celular , Camundongos , República da Coreia
20.
Sci Rep ; 10(1): 1745, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019970

RESUMO

Fertilisation datasets collected from field experiments (n = 21) in tea-producing areas from 2016 to 2018 were used to build a quantitative evaluation of the fertility of tropical soils (QUEFTS) model to estimate nutrient uptake of tea plants, and to investigate relationships between tea yield and nutrient accumulation. The production of 1000 kg spring tea (based on one bud with two young expanding leaves) required 12.2 kg nitrogen (N), 1.2 kg phosphorus (P), and 3.9 kg potassium (K), and the corresponding internal efficiencies (IEs) for N, P, and K were 82.0, 833.3, and 256.4 kg kg-1. To produce 1000 kg summer tea, 9.1 kg N, 0.8 kg P, and 3.1 kg K were required, and the corresponding IEs for N, P, and K were 109.9, 1250.0, and 322.6 kg kg-1. For autumn tea, 8.8 kg N, 1.0 kg P, and 3.2 kg K were required to produce 1000 kg tea, and the corresponding IEs for N, P, and K were 113.6, 1000.0, and 312.5 kg kg-1. Field validation experiments performed in 2019 suggested that the QUEFTS model can appropriately estimate nutrient uptake of tea plants at a certain yield and contribute to developing a fertiliser recommendation strategy for tea production.


Assuntos
Camellia sinensis/química , Nutrientes/química , Chá/química , China , Fertilidade , Fertilizantes , Nitrogênio/química , Necessidades Nutricionais , Fósforo/química , Folhas de Planta/química , Potássio , Estações do Ano , Solo/química
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