Read by QxMD icon Read

HPLC analysis of tea polyphenols

Hui Li, Zhi-Wei Liu, Zhi-Jun Wu, Yong-Xin Wang, Rui-Min Teng, Jing Zhuang
Tea is an important non-alcoholic beverage worldwide. Tea quality is determined by numerous secondary metabolites in harvested tea leaves, including tea polyphenols, theanine, caffeine, and ascorbic acid (AsA). AsA metabolism in harvested tea leaves is affected by storage and transportation temperature. However, the molecular mechanisms underlying AsA metabolism in harvested tea leaves exposed to different storage and transportation temperature conditions remain unclear. Here we performed RP-HPLC to detect dynamic changes in AsA content in tea leaves subjected to high- (38 °C), low- (4 °C), or room-temperature (25 °C) treatments...
2018: Horticulture Research
Jun Zhou, Lili Tang, Chwan-Li Shen, Jia-Sheng Wang
Our recent metagenomics analysis has uncovered remarkable modifying effects of green tea polyphenols (GTP) on gut-microbiota community structure and energy conversion related gene orthologs in rats. How these genomic changes could further influence host health is still unclear. In this work, the alterations of gut-microbiota dependent metabolites were studied in the GTP-treated rats. Six groups of female SD rats (n=12/group) were administered drinking water containing 0%, 0.5%, and 1.5% GTP (wt/vol). Their gut contents were collected at 3 and 6 months and were analyzed via high performance liquid chromatography (HPLC) and gas chromatography (GC)-mass spectrometry (MS)...
August 14, 2018: Journal of Nutritional Biochemistry
Ali Imran, Muhammad Umair Arshad, Muhammad Sajid Arshad, Muhammad Imran, Farhan Saeed, Muhammad Sohaib
BACKGROUND: Recently oxidative stress induced maladies have amplified owing to sedentary lifestyle and monotonous diet. Introduction of plant based biomolecules may be a suitable strategy to cope with the lipid peroxidation. In this context, black tea polyphenols (theaflavin & thearubigins) are in fame among the scientific community as cost effective therapeutic agents owing to their safety, economics, structural diversity and ability to modulate various lipid peroxidation responses by halting the expression of different metabolic targets...
July 18, 2018: Lipids in Health and Disease
Xiaoqin Wang, Qiumei Zeng, María Del Mar Contreras, Lijuan Wang
In Asia, tea seed oils (seed oils from Camellia oleifera, C. chekiangoleosa, and C. sinensis) are used in edible, medicinal, and cosmetic applications. However, these oils differ in their fatty acid contents, and there is little known about their phenolic compounds. Here we analyzed the phenolic compounds of seed oils from three species gathered from 15 regions of China. Twenty-four phenolic compounds were characterized by HPLC-Q-TOF-MS, including benzoic acids (6), cinnamic acids (6), a hydroxyphenylacetic acid, flavanols (4), flavonols (3), flavones (2), and dihydroflavonoids (2)...
December 2017: Food Research International
Chuang Zhang, Claire Li-Chieh Suen, Chao Yang, Siew Young Quek
Tea polyphenols have been a topic of discussion due to their health benefits. Nevertheless, detailed studies on the antioxidant capacity and polyphenol contents of teas in relation to factors including geographical locations, plantation elevations and leaf grades have been limited. In this study, 53 tea samples were analysed to determine the individual and total catechin and theaflavin contents by HPLC and the total antioxidant capacity by Oxygen Radical Absorbance Capacity (ORAC) methods. Results show that the polyphenol (catechins and theaflavins) contents were significantly influenced by plantation location...
April 1, 2018: Food Chemistry
Da-Peng Tong, Ke-Xue Zhu, Xiao-Na Guo, Wei Peng, Hui-Ming Zhou
This paper studied the inhibition of water extract of natural or baked black tea on the activity of α-amylase and α- glucosidase. Baking treatment was found to be one effective way to enhance the inhibition of black tea on both α-amylase and α- glucosidase, and IC50 of water extract of baked black tea (BBTWE) were 1.213mg/mL and 4.190mg/mL, respectively, while IC50 of water extract of black tea (BTWE) were 1.723mg/mL and 6.056mg/mL, respectively. This study further studied the mechanism of the effect of water extract on α-amylase and α- glucosidase using HPLC, circular dichroism, and synchronous fluorescence...
February 2018: International Journal of Biological Macromolecules
Anna Gramza-Michałowska, Andrzej Sidor, Julita Reguła, Bartosz Kulczyński
BACKGROUND: Plant polyphenols are known for their limiting of adverse effects on reactive oxygen species (ROS) in biological systems. The photochemiluminescence (PCL) assay allows to evaluate the antiradical activity of a compound in the presence of a superoxide anion-radical (O •-), which is one of the ROS directly associated with the human body. In this work, determination of the superoxide anion radical scavenging activity of different tea extracts using the PCL assay was performed...
October 2015: Acta Scientiarum Polonorum. Technologia Alimentaria
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
Xue-Bo Zhang, Xian-Feng Du
In order to attenuate the bitter taste and improve the aroma of the summer tieguanyin oolong tea from the Chinese Anxi county, the effects of processing treatment with exogenous laccase and α-galactosidase on tea sensory quality and related compounds were investigated. The solutions of laccase and/or α-galactosidase were sprayed on the tea leaves before the first drying process. The sensory evaluation results showed that the sensory quality of the tea was significantly enhanced with the enzymatic treatment...
June 2015: Food Technology and Biotechnology
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
Shuyuan Liu, Zhi Yu, Hongkai Zhu, Wei Zhang, Yuqiong Chen
BACKGROUND: Natural products have being used as potential inhibitors against carbohydrate-hydrolyzing enzymes to treat diabetes mellitus. Chinese dark tea has various interesting bioactivities. In this study, the active compounds from Qingzhuan dark tea were separated and their anti-diabetic activity was examined using an in vitro enzymatic model. METHODS: The chloroform, ethyl acetate, n-butanol, sediment and residual aqua fractions of a Chinese dark tea (Qingzhuan tea) were prepared by successively isolating the water extract with different solvents and their in vitro inhibitory activities against α-glucosidase were assessed...
September 29, 2016: BMC Complementary and Alternative Medicine
Yi-Fang Li, Shu-Hua Ouyang, Yi-Qun Chang, Ting-Mei Wang, Wei-Xi Li, Hai-Yan Tian, Hong Cao, Hiroshi Kurihara, Rong-Rong He
Camellia sinensis var. puanensis Kurihara (Puan tea) is a kind of ancient tea plant newly found in Jiangxipo and the surrounding areas of Puan County (Guizhou, China). People there always believe that drinking Puan tea is beneficial to the promotion of health and prevention of diseases. However, detailed information on its compositions has not been reported. Therefore, in this study, the varieties and contents of purine alkaloids and polyphenols in Puan tea were identified and determined by HPLC and UFLC-Q-TOF-MS/MS...
February 1, 2017: Food Chemistry
Wuqun Tao, Zhiguang Zhou, Bin Zhao, Tongyu Wei
A simple, rapid and accurate analytical method was developed for the analysis of eight tea catechins and four theaflavins simultaneously in three types of tea (green, black and oolong tea), using ultra high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-MS-MS) in multiple-reaction monitoring (MRM) mode. This method using HPLC-MS-MS in positive mode was performed on a CAPCELL PAK C18 MGIII (2.0mm×100mm, 3μm) column (Shiseido) with the mobile phase consisting of 0...
November 30, 2016: Journal of Pharmaceutical and Biomedical Analysis
Weidong Wang, Huahong Xin, Mingle Wang, Qingping Ma, Le Wang, Najeeb A Kaleri, Yuhua Wang, Xinghui Li
The tea plant [Camellia sinensis (L.) O. Kuntze] is an important commercial crop rich in bioactive ingredients, especially catechins, caffeine, theanine and other free amino acids, which the quality of tea leaves depends on. Drought is the most important environmental stress affecting the yield and quality of this plant. In this study, the effects of drought stress on the phenotype, physiological characteristics and major bioactive ingredients accumulation of C. sinensis leaves were examined, and the results indicated that drought stress resulted in dehydration and wilt of the leaves, and significant decrease in the total polyphenols and free amino acids and increase in the total flavonoids...
2016: Frontiers in Plant Science
Kazuki Ogawa, Sayumi Hirose, Satoshi Nagaoka, Emiko Yanase
The molecular mechanism by which tea polyphenols decrease the micellar solubility of cholesterol is not completely clear. To clarify this mechanism, this study investigated the interaction between tea polyphenols (catechins and oolongtheanins) and cholesterol micelles. A nuclear magnetic resonance (NMR) study was performed on a micellar solution containing taurocholic acid and epigallocatechin gallate (EGCg), and high-performance liquid chromatography (HPLC) analysis was carried out on the precipitate and the supernatant that formed when EGCg was added to a cholesterol-micelle solution...
January 13, 2016: Journal of Agricultural and Food Chemistry
Yuling Tai, Chaoling Wei, Hua Yang, Liang Zhang, Qi Chen, Weiwei Deng, Shu Wei, Jing Zhang, Congbing Fang, Chitang Ho, Xiaochun Wan
BACKGROUND: Tea plants (Camellia sinensis) are used to produce one of the most important beverages worldwide. The nutritional value and healthful properties of tea are closely related to the large amounts of three major characteristic constituents including polyphenols (mainly catechins), theanine and caffeine. Although oil tea (Camellia oleifera) belongs to the genus Camellia, this plant lacks these three characteristic constituents. Comparative analysis of tea and oil tea via RNA-Seq would help uncover the genetic components underlying the biosynthesis of characteristic metabolites in tea...
2015: BMC Plant Biology
Qin Li, Juan Li, Shuoqian Liu, Jianan Huang, Haiyan Lin, Kunbo Wang, Xiaomei Cheng, Zhonghua Liu
Tea (Camellia sinensis L.) is a perennial woody plant that is widely cultivated to produce a popular non-alcoholic beverage; this beverage has received much attention due to its pleasant flavor and bioactive ingredients, particularly several important secondary metabolites. Due to the significant changes in the metabolite contents of the buds and the young expanding leaves of tea plants, high-performance liquid chromatography (HPLC) analysis and isobaric tags for relative and absolute quantitation (iTRAQ) analysis were performed...
2015: International Journal of Molecular Sciences
Zhaoping Li, Paula H Summanen, Julia Downes, Karen Corbett, Tomoe Komoriya, Susanne M Henning, Jenny Kim, Sydney M Finegold
We used pomegranate extract (POMx), pomegranate juice (POM juice) and green tea extract (GT) to establish in vitro activities against bacteria implicated in the pathogenesis of acne. Minimum inhibitory concentrations (MIC) of 94 Propionibacterium acnes, Propionibacterium granulosum, Staphylococcus aureus, and Staphylococcus epidermidis strains were determined by Clinical and Laboratory Standards Institute-approved agar dilution technique. Total phenolics content of the phytochemicals was determined using the Folin-Ciocalteu method and the polyphenol composition by HPLC...
June 2015: Journal of Drugs in Dermatology: JDD
Cindy Leslie A Roberson, Ehab A Abourashed, Nancy Elsharkawy
OBJECTIVE: To investigate the association between cost and (a) chemical constituents and (b) antioxidant activity as quality determinants of select green tea supplements available in the United States. DESIGN/SETTING: Laboratory analysis of green tea using HPLC and antioxidant assay methods. MAIN OUTCOME MEASURES: Correlation between selected quality parameters and daily cost based on the serving size as stated in the label. Quality was defined in terms of (a) catechin levels (validated high-performance liquid chromatography method), (b) total phenolic content (Folin-Ciocalteu method), and (c) antioxidant activity (total antioxidant capacity and diphenylpicryl hydrazyl free-radical scavenging)...
July 2015: Journal of the American Pharmacists Association: JAPhA
Aline Augusti Boligon, Roberta da Silva Jesus, Mariana Piana, Thiele Faccim de Brum, Ritiel Corrêa da Cruz, Natália Mossmann, Margareth Linde Athayde
Recent interest in flavonoids has increased greatly due to their biological and pharmacological activities. Flavonoids consist of a large group of low molecular weight polyphenolic substances, naturally occurring in fruits, vegetables and tea, and are an integral part of the human diet. Quercetin and rutin are bioactive markers of Scutia buxifolia and no analytical methods reported so far, associated with quality control of polyherbal formulations containing this species. Therefore, there is a need to develop a sensitive, simple, rapid and reliable method that can simultaneously determine these markers in their combinations...
October 2015: Journal of Chromatographic Science
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"