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Hplc analysis of tea

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https://www.readbyqxmd.com/read/28764047/an-integrated-antioxidant-activity-fingerprint-for-commercial-teas-based-on-their-capacities-to-scavenge-reactive-oxygen-species
#1
Yu-Jie Guo, Li-Qiong Sun, Bo-Yang Yu, Jin Qi
An integrated antioxidant activity fingerprint, based on on-line screening methods for three reactive oxygen species (ROS: superoxide anion radical, hydrogen peroxide, and hydroxyl radical) was developed to comprehensively evaluate the quality of 12 batches of commercial tea. High-performance liquid chromatography (HPLC) coupled with a chemiluminescent detector was used to determine the antioxidant characteristics of a selection of teas as bioactivity fingerprints. An HPLC-electrospray ionization-mass spectrometry analysis was used to determine the chemical profiles of the teas in the chromatographic fingerprints...
December 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28764022/fast-gradient-hplc-ms-separation-of-phenolics-in-green-tea-to-monitor-their-degradation
#2
Petra Šilarová, Lenka Česlová, Milan Meloun
The degradation of catechins and other phenolics in green tea infusions were monitored using fast HPLC/MS separation. The final separation was performed within 2.5min using Ascentis Express C18 column (50mm×2.1mm i.d.) packed with 2μm porous shell particles. Degradation was studied in relation to the temperature of water (70, 80, 90°C) and the standing time of the infusion (up to 6h). Along with chromatographic separation, the antioxidant properties of the infusions were monitored using two spectrophotometric methods...
December 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28666160/on-line-coupling-of-molecularly-imprinted-solid-phase-extraction-with-liquid-chromatography-for-the-fast-determination-of-coumarins-from-complex-samples
#3
Andrea Machyňáková, Ivona Lhotská, Katarína Hroboňová, Dalibor Šatínský
In this work, an on-line SPE-HPLC method with spectrophotometric detection was developed for the determination of coumarins in complex samples. For the on-line cleanup of samples, a molecularly imprinted polymer was packed into the column cartridge and coupled directly with HPLC (MISPE-HPLC) using a column switching system. The separation of coumarins was performed on a C18 core-shell column (100×4.6mm, 5μm) with a mobile phase consisting of 0.3% acetic acid/acetonitrile with gradient elution at a flow-rate of 1mLmin(-1)...
June 20, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28659938/functional-characterization-of-tea-camellia-sinensis-myb4a-transcription-factor-using-an-integrative-approach
#4
Mingzhuo Li, Yanzhi Li, Lili Guo, Niandi Gong, Yongzheng Pang, Wenbo Jiang, Yajun Liu, Xiaolan Jiang, Lei Zhao, Yunsheng Wang, De-Yu Xie, Liping Gao, Tao Xia
Green tea (Camellia sinensis, Cs) abundantly produces a diverse array of phenylpropanoid compounds benefiting human health. To date, the regulation of the phenylpropanoid biosynthesis in tea remains to be investigated. Here, we report a cDNA isolated from leaf tissues, which encodes a R2R3-MYB transcription factor. Amino acid sequence alignment and phylogenetic analysis indicate that it is a member of the MYB4-subgroup and named as CsMYB4a. Transcriptional and metabolic analyses show that the expression profile of CsMYB4a is negatively correlated to the accumulation of six flavan-3-ols and other phenolic acids...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28649074/neurochemical-and-behavioral-effects-of-green-tea-camellia-sinensis-as-observed-in-animals-exposed-to-restraint-stress
#5
Huma Ikram, Beenish Mirza, Darakhshan Jabeen Haleem
Clinical studies on psychiatric patients suggest that life events stress precipitates depression. The possible involvement of 5-Hydroxy tryptamine (5-HT; Serotonin) in depression and other behavioral deficits is also suggested by clinical studies. As a natural stimulant, green tea (Camellia Sinensis) diminishes stress, worry and anxiety, allowing the brain to focus and concentrate better. Previously we have reported that beneficial effects of green tea might be associated with altered levels of 5-HT, which in turn may help in coping with stress...
March 2017: Pakistan Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28433057/low-cost-humic-acid-bonded-silica-as-an-effective-solid-phase-extraction-sorbent-for-convenient-determination-of-aflatoxins-in-edible-oils
#6
Neng-Zhi Zhou, Ping Liu, Xiao-Chuan Su, Yan-Hua Liao, Ning-Sheng Lei, Yong-Hong Liang, Shao-Huan Zhou, Wen-Si Lin, Jie Chen, Yu-Qi Feng, Yang Tang
Aflatoxins (AFs) are highly toxic, mutagenic, carcinogenic, and teratogenic secondary metabolites produced by the toxigenic fungi Aspergillus flavus and Aspergillus parasiticus. AFs tend to contaminate a wide range of foods which is a serious and recurring food safety problem worldwide. Currently, immunoaffinity chromatography (IAC) has become the most conventional sample clean-up method for determining AFs in foodstuffs. However, IAC method is limited in the large-scale food analysis because it requires the use of expensive disposable cartridges and the IA procedure is time-consuming...
June 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28393854/transcriptomic-analysis-of-the-biosynthesis-recycling-and-distribution-of-ascorbic-acid-during-leaf-development-in-tea-plant-camellia-sinensis-l-o-kuntze
#7
Hui Li, Wei Huang, Guang-Long Wang, Wen-Li Wang, Xin Cui, Jing Zhuang
Ascorbic acid (AsA), known as vitamin C, is an essential nutrient for humans and mainly absorbed from food. Tea plant (Camellia sinensis (L.) O. Kuntze) leaves can be a dietary source of AsA for humans. However, experimental evidence on the biosynthesis, recycling pathway and distribution of AsA during leaf development in tea plants is unclear. To gain insight into the mechanism and distribution of AsA in the tea plant leaf, we identified 18 related genes involved in AsA biosynthesis and recycling pathway based on the transcriptome database of tea plants...
April 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28334752/monitoring-the-consistency-quality-and-antioxidant-activity-of-da-hong-pao-teas-by-hplc-fingerprinting
#8
Lin Wang, Ting Yan, Lanping Yang, Kexia Zhang, Jingming Jia
In the present study, a high performance liquid chromatography (HPLC) method was developed and validated for fingerprint profiling to evaluate the quality consistency of the Da Hong Pao tea. The chromatographic separation was performed on a USA Waters C18 column (4.6 mm × 250 mm, 5 μm, Waters-XBridge Shield RP 18) with gradient elution. The column temperature was maintained at 30°C and the detection wavelength was set at 278 nm. The results demonstrated that the developed HPLC method achieved the desired linearity, precision, accuracy and limit of quantification...
May 1, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28208888/haemoglobinopathies-and-%C3%AE-thalassaemia-among-the-tribals-working-in-the-tea-gardens-of-assam-india
#9
Anju Barhai Teli, Rumi Deori, Sidhartha Protim Saikia
INTRODUCTION: Prevalence of haemoglobinopathies and β-thalassaemia are very high in India but information about its status among the tribals working in the tea gardens of Assam is very less. AIM: The present study was carried out to determine the prevalence of haemoglobinopathies and β-thalassaemia among the tribals working in the tea gardens of Assam. MATERIALS AND METHODS: A total 1204 samples from the tribals working in tea gardens of Assam were analysed for both Complete Blood Count (CBC) and High Pressure Liquid Chromatography (HPLC) for detection of haemoglobinopathies and β-thalassaemia...
December 2016: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/28193433/antioxidant-profiling-of-vine-tea-ampelopsis-grossedentata-off-line-coupling-heart-cutting-hsccc-with-hplc-dad-qtof-ms-ms
#10
Qingping Gao, Ruyi Ma, Lin Chen, Shuyun Shi, Ping Cai, Shuihan Zhang, Haiyan Xiang
Vine tea with strong antioxidant activity is commonly consumed as healthy tea/beverage. However, detailed information about its antioxidants is incomplete. Here, off-line hyphenation of heart-cutting high-speed countercurrent chromatography (HSCCC) with high performance liquid chromatography-diode array detector-quadrupole time-of-flight tandem mass spectrometry (HPLC-DAD-QTOF-MS/MS) were described for systematic profiling antioxidants in vine tea. At first, antioxidants were rapidly screened by 1,1-diphenyl-2-picryl-hydrazyl radical-high performance liquid chromatography (DPPH-HPLC)...
June 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28166943/cold-adaptive-thermogenesis-following-consumption-of-certain-pungent-spice-principles-a-validation-study
#11
Chaitanya Pandit, K R Anilakumar
Identifying a means to activate or potentiate thermogenic mechanisms through ingestion of dietary compounds have important implications in cold endurance and survival. Although many reports discuss the thermogenic potential of spices, it is surprising that none of the studies verify whether consumption of spices can improve cold endurance. In this study, we have attempted to evaluate if ingestion of certain spices can activate heat-generating mechanisms in the body such that a fall in. core body temperature (CBT) can be delayed or prevented when faced with a cold challenge...
February 2017: Journal of Thermal Biology
https://www.readbyqxmd.com/read/28109088/antioxidant-evaluation-and-composition-analysis-of-extracts-from-fuzhuan-brick-tea-and-its-comparison-with-two-instant-tea-products
#12
Qing-An Zhang, Xiao-Li Zhang, Yan-Ying Yan, Xue-Hui Fan
In this paper, the antioxidant capacities and compositions of two commercialized tea products and extracts from Fuzhuan brick tea (FBT) were investigated using three HPLC methods comparing the retention times of injected standards. Principal component analysis and DPPH-spiking HPLC analysis were used to analyze correlation between antioxidant capacity and the compounds detected to screen which compounds contribute to antioxidant activity. Results indicated that all samples contained high amounts of polysaccharides, phenols, and flavonoids and had good antioxidant activity and a high level of correlation among them...
May 1, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/28095717/functional-constituents-of-wild-and-cultivated-goji-l-barbarum-l-leaves-phytochemical-characterization-biological-profile-and-computational-studies
#13
Andrei Mocan, Gökhan Zengin, Mario Simirgiotis, Michaela Schafberg, Adriano Mollica, Dan C Vodnar, Gianina Crişan, Sascha Rohn
Goji (Lycium barbarum L.) leaves are emphasized as a functional tea or as dietary supplements. The phenolic compound profile, antioxidant, enzyme inhibitory, antimicrobial, and antimutagenic activities of leaf extracts from two selected cultivars in comparison with wild-growing plants have been evaluated. HPLC-DAD/ESI-ToF-MS analysis revealed the presence of phenolic acids and flavonoids with chlorogenic acid and rutin being the dominant compounds in the cultivated plants, whereas rutin and kaempeferol-3-O-rutinoside for wild growing ones...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28071811/extraction-of-epigallocatechin-gallate-and-epicatechin-gallate-from-tea-leaves-using-%C3%AE-cyclodextrin
#14
Lu Cui, Yuxuan Liu, Ting Liu, Yahong Yuan, Tianli Yue, Rui Cai, Zhouli Wang
Use of organic solvents to extract phenolic compounds from plants may result in environmental pollution and cause health problems in persons. Replacing organic extraction solvents by green extracting agents without affecting the extraction yield is one of the most pressing problems to be solved. The aim of this study is to evaluate the capacity of β-cyclodextrin (β-CD) to recover phenolic compounds from tea leaves. The extract obtained using the ethanol/water mixture presented the highest total phenolic content, followed by those obtained using β-CD solution and water...
February 2017: Journal of Food Science
https://www.readbyqxmd.com/read/28035976/meadowsweet-teas-as-new-functional-beverages-comparative-analysis-of-nutrients-phytochemicals-and-biological-effects-of-four-filipendula-species
#15
COMPARATIVE STUDY
Daniil N Olennikov, Nina I Kashchenko, Nadezhda K Chirikova
In recent years, the increased popularity of functional beverages such as herbal teas and decoctions has led to the search for new sources of raw materials that provide appropriate taste and functionality to consumers. The objective of this study was to investigate the nutritional, phytochemical profiles and bioactivities of possible functional beverages produced from F. ulmaria and its alternative substitutes (F. camtschatica, F. denudata, F. stepposa). The investigated decoctions were analyzed regarding their macronutrient, carbohydrate, organic acid, amino acid and mineral composition...
December 26, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28035158/screening-and-purification-of-catechins-from-underutilized-tea-plant-parts-and-their-bioactivity-studies
#16
Ajay Rana, Eshita Sharma, Kiran Rawat, Ranjana Sharma, Sarika Verma, Yogendra Padwad, Ashu Gulati
Comparative investigation of major phytoconstituents was performed from various parts of tea plant viz. apical bud, subtending 1st-5th leaf, stem, coarse leaves, flowers, fruits and roots. From the results of comparative RP-HPLC-DAD analysis it was found that underutilized tea parts especially coarse leaves, flowers and fruits contains abundant amount of phenolics (17.5%) and catechins (4-5%). From these underutilized tea plant parts the catechins were extracted and purified and then screened for their anticancer, immunomodulatory effect and antimicrobial activity against food borne pathogens...
November 2016: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/27921291/evaluation-of-capillary-electrophoresis-for-the-analysis-of-rooibos-and-honeybush-tea-phenolics
#17
William J Arries, Andreas G J Tredoux, Dalene de Beer, Elizabeth Joubert, André de Villiers
Rooibos and honeybush are popular herbal teas produced from the shrubs of Aspalathus linearis and Cyclopia spp., respectively, which are indigenous to South Africa. Both herbal teas are rich in polyphenols and their consumption is associated with several health benefits, partly ascribed to their phenolic constituents. Quantification of phenolics in extracts and teas for quality control and research purposes is generally performed using HPLC, although dedicated and often species-specific methods are required...
March 2017: Electrophoresis
https://www.readbyqxmd.com/read/27818668/an-approach-based-on-hplc-fingerprint-and-chemometrics-to-quality-consistency-evaluation-of-matricaria-chamomilla-l-commercial-samples
#18
Agnieszka Viapiana, Wiktoria Struck-Lewicka, Pawel Konieczynski, Marek Wesolowski, Roman Kaliszan
Chamomile has been used as an herbal medication since ancient times and is still popular because it contains various bioactive phytochemicals that could provide therapeutic effects. In this study, a simple and reliable HPLC method was developed to evaluate the quality consistency of nineteen chamomile samples through establishing a chromatographic fingerprint, quantification of phenolic compounds and determination of antioxidant activity. For fingerprint analysis, 12 peaks were selected as the common peaks to evaluate the similarities of commercial samples of chamomile obtained from different manufacturers...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27765257/composition-distribution-and-risk-of-total-fluorine-extractable-organofluorine-and-perfluorinated-compounds-in-chinese-teas
#19
Ruobing Zhang, Hong Zhang, Qingwu Chen, Ji Luo, Zhifang Chai, Jincan Shen
To explore the residual characteristics of fluorine and perfluorinated compounds (PFCs) in tea, the total fluorine (TF), extractable organofluorine (EOF) and PFCs in 19 Chinese commercial teas of five categories were measured using cyclic neutron activation analysis combined with HPLC-MS/MS. The results showed that fluorine mainly existed as inorganic fluorine in teas, and identified fluorine (∑PFCs quantified as F) only accounted for 0.023-0.41% of EOF, indicating that most EOF in tea were still unknown...
March 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/27697574/combination-of-hplc-ms-and-qams-as-a-new-analytical-approach-for-determination-of-saponins-in-ginseng-containing-products
#20
Andrey Stavrianidi, Elena Stekolshchikova, Anna Porotova, Igor Rodin, Oleg Shpigun
Conventional liquid chromatographic methods coupled with ultraviolet detection with low-wavelength range are lacking selectivity and sensitivity to determine both polar and less polar ginsenosides. Also the lack of standard substances for such quality control methods is leading to development of the approaches using single standard for quantitative analysis of multi-component system (QAMS). The objective of present study was to establish and compare for the first time liquid chromatography-ultraviolet detection and liquid chromatography-mass spectrometry QAMS methods for the simultaneous determination of protopanaxatriol-type and protopanaxadiol-type ginsenosides in a variety of ginseng products...
January 5, 2017: Journal of Pharmaceutical and Biomedical Analysis
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