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1.
HPLC内标标准曲线法测定茶叶中4种儿茶素和咖啡因 总被引：1，自引：0，他引：1
选用葛根素作为内标物质,利用内标标准曲线法建立高效液相色谱同时测定茶叶中（-）表没食子儿茶素（EGC）,（-）表没食子儿茶素没食子酸酯（EGCG）,（-）表儿茶素（EC）,（-）表儿茶素没食子酸酯（ECG）,咖啡因（CAF）5种组分的分析方法.采用C18柱,甲醇和0.05%三氟乙酸水溶液为流动相,梯度洗脱,DAD检测器,检测波长278 nm.结果表明,各组分的色谱峰均达到基线分离,该方法重复性好,灵敏度高,回收率高,已用于不同种类26个茶叶样品的测定.以这5种活性成分为指标,采用聚类分析法可对不同来源的样品进行统计分析. 相似文献
2.
马大鹏 《赤峰学院学报(自然科学版)》2012,(5):17-18
表没食子儿茶素没食子酸酯(epigallocatechin gallate)简称EGCG)是茶叶中茶多酚的主要活性成分,它是一种多羟基酚,因此具有很强的抗氧化能力,是一种天然、高效、安全的抗氧化剂,同时也是一种理想的天然药物.目前已成功应用在食品、油脂、医疗保健、日用品等诸多领域.同时,对EGCG的纯化研究也吸引了研究人员的目光,本文对EGCG的应用以及纯化研究进展做了简要概述. 相似文献
3.
以 HPLC-ESI-MS ／TOF 为研究手段,应用正交实验、直观分析和方差分析等方法对仪器参数进行优化,并以茶叶中的茶多酚为研究对象,建立了大叶茶中 EGC,EC,EGCG 和 ECG 这4种儿茶素组分的质量分数质谱测定方法。结果表明,该方法可在6 min 内实现单个样品中茶多酚质量分数的快速定量,且方法简单、快速、灵敏度高、线性范围宽等,可用于茶叶中茶多酚质量分数的快速定量。 相似文献
4.
采用高效液相色谱法对不同茶叶中的表没食子儿茶素没食子酸酯(EGcG)的含量进行分析.采用C18色谱柱(4.6mm×250 mm,5μm),流动相为甲醇:水:乙酸(23:75:2,v/v),流速1.0 mL·min-1,柱温35℃,检测波长为272nm.EGCG线性范围为0.11～1.71μm,相关系数r=0.9996,平均回收率98.7%,RSD为0.7%.本方法分析速度快,灵敏度高,分离效果好,可作为测定茶叶中EGCG含量的方法. 相似文献
5.
研究了没食子儿茶素没食子酸酯（EGCG）对人肝癌细胞BEL-7402增殖凋亡及对信号转导蛋白和转录激活因子3（Stat3）蛋白及磷酸化Stat3蛋白表达的影响.应用MTT法检测不同浓度EGCG对BEL-7402细胞增殖的抑制作用,用流式细胞仪分析细胞的凋亡率,用ELISA方法检测EGCG对Stat3蛋白及磷酸化的Stat3蛋白表达的影响.结果表明：EGCG有抑制肝癌细胞增殖促进凋亡的作用,并呈剂量依赖性.ELISA结果显示EGCG能降低磷酸化Stat3蛋白的表达水平.EGCG能抑制肝癌细胞的增殖促进凋亡,其机制可能有与下调磷酸化的Stat3蛋白的表达有关. 相似文献
6.
Yue ZHANG Hai-peng LV Cheng-ying MA Li GUO Jun-feng TAN Qun-hua PENG Zhi LIN 《Journal of Zhejiang University. Science. B》2015,16(2):103-112
目的:从茶树中克隆一种可以催化表没食子儿茶素没食子酸酯(EGCG)生成甲基化EGCG的酶——咖啡酰辅酶A氧甲基转移酶(CCo AOMT),实现甲基化EGCG的酶学合成,为甲基化EGCG的进一步开发利用提供理论依据和技术指导。创新点:本研究首次从茶树中克隆了一条CCo AOMT基因组序列;分析了CCo AOMT基因在不同茶树品种和不同成熟度茶鲜叶中的基因表达规律;证明了CCo AOMT具有催化合成甲基化EGCG的生物活性。方法:采用聚合酶链式反应(PCR)和序列分析获得CCo AOMT的编码序列和基因组序列;采用高效液相色谱-四级杆-飞行时间串联质谱技术(HPLC-QTOF-MS)分析酶促反应生成的甲基化EGCG产物(图4);采用实时荧光定量PCR分析CCo AOMT基因的表达差异(图5)。结论:本研究从茶树中克隆了CCo AOMT基因的编码序列(738 bp)和基因组序列(2678 bp),明确了该基因具有4个内含子和5个外显子;揭示了CCo AOMT可以催化EGCG生成EGCG4"Me、EGCG3"Me和EGCG3’Me等多种甲基化产物;证明了CCo AOMT具有催化生成甲基化EGCG的活性;并发现该基因的表达量高低与茶鲜叶的成熟度呈正相关关系。 相似文献
7.
以茶叶籽为原料,采用超临界CO2萃取得到茶叶籽油,通过分子蒸馏富集提取茶叶籽油中抗氧化成分,并采用UHPLC-TOF-MS分析其组成。结果表明,CO2流速对萃取速率影响较大,采用超临界CO2梯度萃取的模式,不同萃取阶段得到的茶叶籽油的酸价存在一定规律,在萃取初期,茶叶籽油的酸价较高,随着萃取过程的进行,酸价逐渐降低,说明游离脂肪酸更容易溶解在超临界CO2中。茶叶籽油分子蒸馏馏出物中主要的抗氧化成分包括：山茶甙C,表儿茶素没食子酸酯,表阿福豆素,表儿茶素及表没食子儿茶素等5种。 相似文献
8.
用高效液相色谱仪（HPLC）分析普洱生茶、熟茶与红茶的主要化学成分含量（质量分数）.结果表明：普洱生茶、熟茶及红茶在278 nm处具有截然不同的色谱图及化学成分.普洱生茶保留了较多的ECG,EGCG以及C等多酚类物质;红茶因其酶促作用形成了一系列的氧化产物—茶黄素类和茶红素类,也保留了一定量的未氧化的多酚类物质;而普洱熟茶的湿热作用却只形成一定量的TR,未氧化多酚类物质的含量（质量分数）也较低,ECG和EGCG几乎完全氧化,且氧化产物中不含茶黄素类. 相似文献
9.
为了同时测定女儿茶中4种儿茶素（DC,EC,GC和EGC）及咖啡因（CAF）,对女儿茶质量评判奠定基础,笔者采用伊利特C18（250mm×4.6mm）色谱柱,甲醇-水-乙酸为流动相,流速1ml/min,检测波长278nm,在所选用条件下,各组分理想分离,效果良好。 相似文献
10.
目的:通过测定茶树叶片的分解速率及养分释放规律,研究茶多酚在茶树叶片分解过程中的作用。创新点:测定了茶树叶片在茶园地表的分解速率和养分释放规律,并确定了茶多酚/氮素比值在茶树叶片短期分解过程中的主导作用。首次利用高效液相色谱法监测了分解过程中儿茶素的变化规律。方法:采集成熟的茶树叶片,在室内风干后利用分解袋法测定其分解速率。分解袋放置于茶园地表用于模拟田间条件,逐月收集分解样品。实验结束后,测定各月份叶片的干重残留量、月均干重损失率、多酚等有机组分含量以及各元素含量。结论:茶树叶片的干物质损失规律可以"两相分解模型"进行描述,茶多酚/氮素比值是调控分解速率的主要因素。分解过程中,茶多酚的转换十分迅速,同时儿茶素单体的结构影响其分解速率:大部分的儿茶素单体在分解初始两个月内迅速消失,没食子酸(GA)、儿茶素没食子酸酯(CG)、儿茶素(GC)在分解后期少量检出,而其他儿茶素已不在检测限内。茶树叶片中大量多酚的存在及其特有性质可能影响着叶片中的养分释放过程。 相似文献
11.
通过对普洱茶的特级、三级、九级三个茶样进行五分钟沸水冲泡处理,测出相应的茶多酚和游离氨基酸含量．探讨普洱茶在冲泡过程中,茶多酚和游离氨基酸的浸出规律．研究表明：随着级别的降低,茶多酚和氨基酸含量明显减少;随着冲泡次数的增加,茶多酚和氨基酸的浸出含量也随之减少． 相似文献
12.
采用高效液相色谱法对3种不同发酵类型的茶叶中茶多酚的含量进行测定和比较分析．方法的变异系数小于4．38％,回收率为96．6％～104．0％．其分析结果为：3种不同发酵类型的茶叶中茶多酚的含量由多到少的顺序为：不发酵的绿茶,半发酵青茶,全发酵红茶,即茶叶中茶多酚的含量随着发酵程度增大而减少． 相似文献
13.
Dong-mei Fan Kai Fan Cui-ping Yu Ya-ting Lu Xiao-chang Wang 《Journal of Zhejiang University. Science. B》2017,18(2):99-108
Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols. 相似文献
14.
Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifica tion of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-ch a in acyl-derivative of epigallocatechin-3-o-gallate (EGCG) was first isol ated fro m purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v ). The molecular structure of the acyl-derivative, Epigallocatechin-3-O- gall ate-4′-O-hexadecanate , was elucidated by means of elemental analysis, I R, 1H-NMR and MS spectra. 相似文献
15.
Le Ying De-dong Kong Yuan-yuan Gao Feng Yan Yue-fei Wang Ping Xu 《Journal of Zhejiang University. Science. B》2018,19(3):199-210
Phenolics, as the main bioactive compounds in tea, have been suggested to have potential in the prevention of various human diseases. However, little is known about phenolics and their bioactivity in Zhangping Narcissue tea cake which is considered the most special kind of oolong tea. To unveil its bioactivity, three phenolic-enriched extracts were obtained from Zhangping Narcissue tea cake using ethyl acetate, n-butanol, and water. Their main chemical compositions and in vitro bioactivity were analyzed by high-performance liquid chromatography (HPLC) and ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The ethyl acetate fraction (ZEF) consisted of higher content of phenolics, flavonoids, procyanidins, and catechin monomers (including epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and gallocatechin gallate (GCG)) than n-butanol fraction (ZBF) and water fraction (ZWF). ZEF exhibited the strongest antioxidant capacity in vitro due to its abundant bioactive compounds. This was validated by Pearson correlation and hierarchical clustering analyses. ZEF also showed a remarkable inhibition on the growth, migration, and invasion of 4T1 murine breast cancer cells. 相似文献
16.
Lipophilic tea polyphenols (LTP) were prepared by catalytic esterification of green tea polyphenols (GTP) with hexadecanoyl
chloride. A novel long-chain acyl-derivative of epigallocatechin-3-o-gallate (EGCG) was first isolated from purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent
system composed of n-hexane-ethyl acetate-methanol-water (1∶1∶1∶1, v/v). The molecular structure of the acyl-derivative, Epigallocatechin-3-O-gallate-4′-O-hexadecanate, was elucidated by means of elemental analysis, IR,1H-NMR and MS spectra.
Project (No. 200010) supported by Zhejiang Provincial Natural Science Foundation, China 相似文献
17.
Tea polyphenols have been shown to have anticancer activity in many studies.In the present study,we investigated effects of theaflavin-3-3'-digallate(TF3),one of the major theaflavin monomers in black tea,in combination with ascorbic acid(AA),a reducing agent,and(-)-epigallocatechin-3-gallate(EGCG),the main polyphenol presented in green tea,in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay showed that the 50% inhibition concentrations(IC50) of TF3,EGCG,and AA on SPC-A-1 cells were 4.78,4.90,and 30.62 μmol/L,respectively.The inhibitory rates of TF3 combined with AA(TF3+AA) and EGCG combined with AA(EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%,respectively.Flow cytometry analysis showed that TF3+AA and EGCG+AA obviously increased the cell population in the G0/G1 phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%,respectively.TF3-treated cells exhibited 65.3% of the G0/G1 phase at the concentration of its IC50.Therefore,TF3+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells,and significantly held SPC-A-1 cells in G0/G1 phase.The results suggest that the combination of TF3 with AA or EGCG with AA enhances their anticancer activity. 相似文献