中压硅胶柱层析连续纯化茶叶中EGCG及ECG的研究

采用一种连续中压硅胶柱层析分离高纯度表没食子儿茶素没食子酸酯(EGCG)及表儿茶素没食子酸酯(ECG),原料为含量高于 98 % 的茶多酚.连续中压柱层析分离工艺条件为:160～280μm 硅胶为填充料,1 200 mm×80 mm 的自制不锈钢中压层析柱,洗脱液为乙酸乙酯-石油醚-甲酸(体积比6:4:1),洗脱流速为 30 mL/min,负载量为 35 g/kg(以硅胶计,下同),可以得到纯度大于 98 % 的EGCG产品(平均回收率为 85.5 %)和 98 % 的ECG产品(平均回收率均为 80.3 %).回收的洗脱剂先校正pH值,再经薄层层析校正后可重复使用.使用后的层析柱用乙酸乙酯再生,石油醚为平衡剂平衡,平衡后的层析柱可重复使用.     

松树皮多聚原花青素片段化产物的分离鉴定及活性

采用多种柱层析手段,分别从基于茶多酚的思茅松和马尾松树皮多聚原花青素片段化反应产物中分离得到1个主要产物。通过MS、1H NMR和13C NMR波谱解析,其化学结构鉴定为(-)-表儿茶素-(4β-8)-(-)-表没食子儿茶素3-O-没食子酸酯(1)。结果表明,茶多酚中的(-)-表没食子儿茶素3-O-没食子酸酯(EGCG)在片段化反应中扮演着重要角色,化合物1是EGCG通过4β-8与(-)-表儿茶素C-4位上的正离子键合形成而来。采用DPPH、ABTS自由基清除活性测定方法评价了化合物1的抗氧化活性,其清除DPPH、ABTS自由基的能力均高于茶多酚、多聚原花青素及其片段化总产物,SC50值分别为6.12±0.03 g/m L和41.41±0.66 g/m L。     

杨梅不同部位单宁含量与结构研究

对杨梅的叶、枝和树皮的总酚含量与可溶缩合单宁含量进行了测定,并利用基质辅助激光解吸附飞行时间质谱(MALDI-TOFMS)详细研究了不同部位中缩合单宁的类型、聚合度及聚合物的分布情况。结果表明:树皮的总酚含量最高(43.56%),叶次之(34.69%),枝最低(18.53%);树叶的可溶缩合单宁含量最高(25.67%),皮次之(17.93%),枝最低(8.01%);3组分的缩合单宁都以(表)棓儿茶素-3-O-棓酸酯(EGCG/GCG)为基本结构单元的原翠雀定,且大部分聚合物的结构单元之间存在A型和B型两种连接方式,但其中叶和枝缩合单宁的聚合度要大于树皮。     

表棓儿茶素棓酸酯体外氧化及其低聚产物形成的研究

为控制儿茶素类低聚氧化产物形成条件,以表棓儿茶素棓酸酯(EGCG)为代表进行体外化学氧化,通过对产物的HPLC-MS分析确定研究对象,即EGCG氧化低聚物(EOP),其主要有3种低聚产物:产物1 m/z 911,产物2m/z 929,产物3m/z 911.产物1和产物3为EGCG脱氢二聚体;产物2为EGCG醌式二聚体.反应条件的研究表明,随温度升高EGCG氧化程度加剧,EOP生成量也随之增加,但温度达40℃时,EOP的生成量在氧化10 min后下降;体系pH值增大可加剧EGCG氧化,但pH值9.0时,EOP的生成量在15min后有所下降;随氧化剂所占质量比的增大,EGCG氧化程度加大,但EOP的生成量并不与之成正相关.EOP形成的最佳条件为:反应温度25℃,pH值7.5,氧化剂与底物的质量比1.5∶1,氧化时间15 min.     

EGCG-Cu络合物与牛血清蛋白相互作用研究

表没食子儿茶素没食子酸酯(EGCG)为茶叶中主要活性成分之一,具有抑制细胞增殖,诱导细胞凋亡,抑制肿瘤血管生成等多种生理活性功能。EGCG能够与蛋白质及金属离子形成络合物,从而影响其各种生理活性功能。笔者利用荧光猝灭法分别研究了EGCG及其Cu(Ⅱ)络合物(EGCG-Cu)与牛血清白蛋白(BSA)的相互作用,并分析了Cu(Ⅱ)的存在对EGCG与BSA相互作用的影响。利用Stern-Volmer曲线分析了EGCG及其Cu(Ⅱ)络合物分别与BSA络合反应中不同的荧光猝灭机理,采用Stern-Volmer方程及不同Stern-Volmer修正方程计算得到3种不同反应体系中EGCG与BSA相互作用的结合常数。结果表明:随EGCG和EGCG-Cu络合物样品浓度的增加,BSA出现典型的荧光猝灭现象,表明EGCG和EGCG-Cu络合物均与BSA发生了相互作用。反应溶液中Cu(Ⅱ)的存在会改变EGCG与BSA的相互作用形式,并降低EGCG与BSA相互作用的结合常数。此外,EGCG与Cu(Ⅱ)络合后能够提高EGCG与BSA之间的结合常数。研究结果可为深入分析EGCG在体内的各种生理活性功能提供参考。     

SA对低温胁迫后枇杷幼果AsA-GSH循环酶系统的影响

研究水杨酸处理对早钟6号枇杷幼果AsA-GSH循环酶系统的影响,探讨SA对枇杷幼果抗寒性的作用机理。结果表明:采用40和70mg·L-1的SA处理可提高低温胁迫后枇杷幼果还原型谷胱甘肽(GSH)含量,降低氧化型谷胱甘肽(GSSG)含量,导致GSH/GSSG比率的上升,同时也提高低温胁迫后枇杷幼果谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPX)和谷胱甘肽-S-转移酶(GST)的活性,启动细胞的解毒功能,从而降解低温胁迫后所产生的过量过氧化产物。此外,SA处理还可提高低温胁迫后枇杷幼果抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)和单脱氢抗坏血酸还原酶(MDAR)活性以及还原型抗坏血酸(AsA)含量,降低氧化型抗坏血酸(DHA)、过氧化氢(H2O2)和丙二醛(MDA)含量以及相对电导率(REC),导致AsA/DHA比率的上升,提高枇杷幼果组织内部的抗氧化能力,从而起到保护作用。SA处理可提高低温胁迫后枇杷幼果的抗氧化性,增强其抗寒能力,其中以70mg·L-1的SA处理效果较好。     

抗氧化剂和吸附剂促进银杏愈伤组织生长及防止褐化作用研究

探讨了抗氧化剂柠檬酸、抗坏血酸(VC)、植酸(PA)和聚乙烯吡咯烷酮(PVP),吸附剂活性炭(AC)对银杏愈伤组织继代培养中细胞生长和褐化的影响,结果表明:柠檬酸0.2 g.L-1对银杏继代细胞生长速率促进最大,可达11.354%;15 mg.L-1VC抗褐化效果最好,叶绿素含量可达0.248%。综合细胞生长和抗褐化效果,最佳处理为柠檬酸0.2 g.L-1。     

黑荆树原花色素二聚体的分离制备及抗氧化活性研究

以黑荆树皮为原料,采用超声波辅助提取技术提取原花色素,并利用溶剂萃取法得到低聚原花色素含量较高的乙酸乙酯萃取物;进一步通过葡聚糖凝胶Sephadex LH-20柱和快速蛋白液相色谱(FPLC)分离纯化制备黑荆树原花色素二聚体,并采用HPLC-MS对产物结构进行了鉴定。结果表明:超声波辅助提取原花色素的粗提物得率高达50.21%,其中含原花色素为40.75%,乙酸乙酯萃取物经葡聚糖凝胶Sephadex LH-20柱可得液相纯度约为60%的组分I(得率约为5%);组分I经FPLC分离,水-甲醇为流动相,得到纯度为91.72%的原花色素二聚体(得率约为13%);HPLC-MS分析表明,原花色素二聚体相对分子质量为578,可能是由原花青定的C-4键与原刺槐定的C-8键相连。黑荆树原花色素二聚体对DPPH自由基的清除率分析表明:原花色素二聚体的抗氧化活性总体高于儿茶素以及表没食子儿茶素没食子酸酯(EGCG)标样,当二聚体浓度为60μmol/L时对DPPH清除率大于80%,高于EGCG(约为68%)和儿茶素(约为50%)。     

冬枣冷藏期间果皮和果肉抗氧化物质含量及其抗氧化活性的变化

以白熟期冬枣为试材,对其冷藏期间果皮和果肉抗氧化物质含量及其体外抗氧化活性的变化进行测定,并采用HPLC-MS定性定量检测果皮中4种形态酚(游离酚、酯化酚、苷化酚和结合酚)含量的变化,分析果皮和果肉抗氧化物质含量与其抗氧化能力的关系及其主要形态酚酸的抗氧化能力.结果表明:随着贮藏期的延长,果肉的总酚、类黄酮和抗坏血酸的含量及其抗氧化能力均先升后降；而果皮中总酚、类黄酮和抗坏血酸含量及其抗氧化能力则持续下降；贮藏期间果皮中总酚、类黄酮和花青素含量始终极显著高于果肉(P＜0.01).相关分析表明:果皮中除花青素外的活性成分与体外抗氧化活性均显著相关,其抗氧化能力也极显著高于果肉(P＜0.01).贮藏期间,果皮中游离酚主要含有儿茶素、表儿茶素和芦丁,它们的含量变化呈先增加后降低趋势,且极显著高于其他3种形态酚,酯化酚和苷化酚含量较低,结合酚中以香豆酸含量略高,总酚中游离酚是主要的抗氧化活性物质.     

SNP与K~+、Ca~(2+)互作促进白桦悬浮细胞中白桦酯醇累积的初步研究

[目的]探究一氧化氮供体硝普钠(SNP)对白桦悬浮细胞中K~+、Ca~(2+)和白桦酯醇累积的影响及外源K~+、Ca~(2+)与SNP互作对白桦酯醇累积的影响。[方法]利用高效液相色谱法、原子吸收光谱法及比色法分别测定白桦酯醇、K~+及Ca~(2+)含量。[结果]SNP处理对白桦悬浮细胞中K~+、Ca~(2+)的累积存在浓度和时间效应,其中1 mmol·L-1SNP处理12 h时K~+含量最高,是对照组的1.47倍,而Ca~(2+)含量在5 mmol·L-1SNP处理96 h时最高,是对照组的1.50倍。1 mmol·L-1SNP与不同浓度KCl共同处理后,白桦酯醇含量高于单独SNP与KCl处理,其中,SNP与0.1 g·L-1KCl共同处理时,白桦酯醇的积累量最大,是单独SNP处理1.72倍,是单独KCl处理2.33倍。1 mmol·L-1SNP与不同浓度Ca Cl2互作处理后,白桦酯醇含量高于单独SNP与Ca Cl2处理,其中,SNP与0.1 g·L-1Ca Cl2共同处理时,白桦酯醇的积累量最大,是单独SNP处理2.75倍,是单独Ca Cl2处理2.18倍。[结论]SNP处理诱导了白桦悬浮细胞中K~+和Ca~(2+)的合成和白桦酯醇的累积,SNP分别与K~+或Ca~(2+)互作可以更好的促进白桦悬浮细胞中白桦酯醇的累积,同时推测SNP诱导的K~+、Ca~(2+)在一定程度上介导了白桦酯醇的累积。     

Epigallocatechin gallate content change of the fresh tea leaf homogenates extracted by different methods in extraction and preservation

Introduction Tea polyphenols, extracted from tea leaves, is a hydroxyl phenol compound. Of the components of green tea (Camellia sinensis), the content of (?)-epigallocatechin gallate (EGCG) is high, and this catechin has been extensively studied (Harold …     

中国茶产业发展现状分析

我国茶园总面积、茶叶总产量及绿茶、特种茶、乌龙茶出口创汇呈现持续上升的态势;茶叶功能成分的深度开发与利用,使得茶叶提取物作为膳食补充剂、医药原料及化妆品原料等在国际市场上呈急剧攀升之势。对比分析茶叶等植物原材料的销售产值与茶叶等植物提取物的销售产值,指出在世界茶产业面临供过与求的情况下,扬长避短,生产绿茶、特种茶、乌龙茶等具有国际竞争力的茶叶产品,加大茶叶深加工产品的开发与利用,出口符合国际保健品市场需要的茶叶功能产品,促进茶产业升级换代,是我国茶产业经济增长及发展的重要途径。     

"湘妃翠"鲜叶与成品茶主要品质成分的季节变化

采用氨基酸自动分析仪、高效液相色谱和茶叶国标检测方法测定分析了不同季节“湘妃翠”鲜叶及其成品茶中游离氨基酸、儿茶素、咖啡碱、茶多酚和水浸出物的含量。结果表明:鲜叶与成品茶中游离氨基酸、儿茶素、咖啡碱、茶多酚和水浸出物含量等的品质成分的季节变化明显,趋势一致,春季明显优于夏秋季、秋季优子夏季;与鲜叶的品质成分状况相比,成品茶的品质成分状况明显改善,奠定了感官品质的生化基础。根据分析结果提出了“湘妃翠”品种在夏秋季生产普通绿茶而不生产名优茶的建议。     

Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa,coffee, tea)

Polyphenols occurring in cocoa, coffee and tea can have a role in the prevention of cariogenic processes, due to their antibacterial action. Cocoa polyphenol pentamers significantly reduce biofilm formation and acid production by Streptococcus mutans and S. sanguinis. In the same way, trigonelline, caffeine and chlorogenic acid occurring in green and roasted coffee interfere with S. mutans adsorption to saliva-coated hydroxyapatite beads. Studies carried out on green, oolong and black tea indicate that tea polyphenols exert an anti-caries effect via an anti-microbial mode-of-action, and galloyl esters of (−)-epicatechin, (−)-epigallocatechin and (−)-gallocatechin show increasing antibacterial activities. The anti-cariogenic effects against α-haemolytic streptococci showed by polyphenols from cocoa, coffee, and tea suggest further studies to a possible application of these beverages in the prevention of pathogenesis of dental caries.     

The therapeutic effects of EGCG on vitiligo

Epigallocatechin-3-gallate (EGCG) is one of the main chemical constituents of green tea, which has been used as an important traditional Chinese medicine. Green tea has anti-inflammatory, anti-oxidant, and immunomodulatory properties. However, the effects of EGCG on vitiligo are not known. We assessed the role of EGCG in vitiligo induced by monobenzone in mice. We demonstrated that EGCG: delayed the time of depigmentation; reduced the prevalence of depigmentation; and decreased the area of depigmentation. Examination of depigmented skin treated with EGCG by reflectance confocal microscopy suggested increased numbers of epidermal melanocytes and histologic examination showed decreased perilesional accumulation of CD8⁺ T cells. To further investigate the mechanism of the anti-inflammatory effects of EGCG, levels of inflammatory mediator tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-6 were tested by enzyme-linked immunosorbent assay. Serum cytokine levels were significantly decreased after administration of EGCG compared with the model group. These results suggested that EGCG may have protective effects against vitiligo, and that it could contribute to suppression of activation of CD8⁺ T cells and inflammatory mediators. Based on these results, 5% EGCG was considered to be the most suitable concentration for treating vitiligo, and was used for further study. In addition, we investigated the gene-expression profile of this model in relation to EGCG. Using a 4 × 44 K whole genome oligo microarray assay, 1264 down-regulated genes and 1332 up-regulated genes were recorded in the 5% EGCG group compared with the model group, and selected genes were validated by real-time polymerase chain reaction. Our study demonstrated that EGCG administration was significantly associated with a decreased risk of vitiligo. EGCG could be a new preventive agent against vitiligo in the clinical setting.     

Synergetic deodorant effect and antibacterial activity of composite paper containing waste tea leaves

Composite paper containing waste tea leaves was prepared to investigate the effective utilization of waste tea leaves as deodorant material. Paper containing waste green tea leaves did not have increased deodorizing ability compared with controls either against acidic odors such as hydrogen sulfide and acetic acid gases or against neutral odors such as formaldehyde and acetaldehyde gases. In contrast, the paper had excellent deodorizing ability against basic odors such as ammonia and trimethylamine gases. It was observed during additional tests conducted on paper samples containing 60 wt% waste leaves of oolong tea, black tea, pu-erh tea, or hojicha, that all the samples reduced the ammonia concentration to below 1 ppm, which is the threshold concentration for olfactory recognition, within 30 min. Further, paper containing waste green tea leaves was found to decrease the odor residual rate to 5.1% in 30 min even for a waste tea leaf content of 10 wt%. The excellent deodorizing ability of the paper could be attributed to the chemical reactions between odorous substances and the catechins found in tea leaves. After the deodorization of ammonia, paper containing waste green tea leaves was found to have increased antibacterial activity against Staphylococcus aureus.     

Improving the antibacterial activity against Staphylococcus aureus of composite sheets containing wasted tea leaves by roasting

We used various kinds of wasted tea leaves to develop composite sheets with antibacterial properties. Antibacterial tests showed that the number of viable bacterial cells for the sheet containing wasted green tea leaves was around 10:⁶–10⁷ CFU/ml after 18 h culture compared to 108 CFU/ml for a tea-free sheet. This indicates that cell growth was signifi cantly inhibited. For sheets containing other types of tea leaves (oolong, black, hojicha, and pu-erh), living cells were not found, indicating that these sheets had superior antibacterial effects. Living cells were also not found in sheets containing wasted black tea leaves or roasted tea leaves at a concentration of 60% by weight after 6 h cultivation. Therefore, roasting treatment of wasted green tea leaves was examined to improve the antibacterial activity of the sheet. In particular, the focus was on structural conversion of catechins by heating.     

无公害施肥对茶园土壤理化性质的影响[]

文章研究无公害施肥对粤东乌龙茶茶园土壤自然含水量和土壤容重等物理性质、有机质、全氮、碱解氮等土壤养分的影响,结果表明：铺草、施绿肥、施有机肥均能提高土壤自然含水量和有机质质量比,而施有机肥对提高土壤有机质质量比的效果最好;施绿肥和铺草对于提高土壤全氮和碱解氮质量比的效果不明显,而施有机肥可以明显提高土壤全氮和碱解氮质量比,因此粤东各地茶园可以因地制宜改善本地的茶园土壤,采取施有机肥结合铺草措施,保证土壤肥力供应和含水量。     

不同品种茶叶的抗癌活性研究

本研究应用分光光度法和高效液相色谱法测定了4种不同茶叶的化学成分和儿茶素的含量,结果表明,茶叶品种不同,其化学成分、儿茶素的组成与配比差异较大,这是决定其抗癌作用的物质基础。     

林茶复合经营研究与应用

本文系统地总结了林茶复合经营技术的历史沿革、3种应用类型及经营技术、科学研究成果和研究现状, 并就间作茶园树种选择原则、系统结构优化及生态学机理等研究领域提出了新的研究方向。