Evaluation of Chromogenic Reaction Ability of Hydrochloric Acid (Sulfuric Acid)-vanillin by the Colorimetry for Determining Tea Catechins Aggregates

测定了茶叶儿茶素及绿茶、红茶中的儿茶素与盐酸(硫酸)-香草醛的显色反应水平,通过对反应系数、准确度、精密度测定和比较,评价了儿茶素与酸性香草醛的显色反应能力.结果表明:两种酸性体系对儿茶素反应灵敏,且呈高度线性相关(R2盐酸=0.9976±0.0014,R2硫酸=0.9978±0.0018);显色反应系数上,盐酸法为34.77±10.00(绿茶)、83.83±20.13(红茶);硫酸法为39.65±8.97(绿茶)、86.68±19.87(红茶),均低于茶叶儿茶素总量经验计算公式中Roberts系数(145.68).盐酸-香草醛显色反应体系的回收率为94.22％±3.33％(绿茶)、99.71％±1.39％(红茶),精密度的变异系数为0.08％(绿茶)、0.07％(红茶);硫酸-香草醛显色反应体系的回收率为95.78％±1.95％(绿茶)、99.95％±2.56％(红茶),精密度的变异系数为0.07％(绿茶)、0.06％(红茶),表明两种体系均能测定茶叶儿茶素总量.来源于不同茶类、等级茶的儿茶素类与酸性香草醛的显色能力差异极显著(F=37.434＞F0.01[1,5]=6.61),说明两种反应体系均能客观表征茶叶儿茶素总量.由经验公式计算法得到的回收率(绿茶120.59％±34.86％,红茶114.09％±0.20％)和变异系数(绿茶28.91％,红茶0.17％)均不稳定,且其测定的儿茶素总量也偏高于实际值.     

木麻黄针叶中矿质元素的快速测定

用原子吸收分光光度计对１．５ｍｏｌ．Ｌ－１盐酸浸提木麻黄针叶中钠、钙、镁等矿质元素进行测定，具有快速简单、容易操作、减少污染等特点。实验结果表明：用该方法测定木麻黄针叶中钠、钙、镁等矿质元素，变异系数小、回收率高，具有较高的精密度和较好的重现性。与国家标准法：硫酸—高氯酸湿灰化法比较，测定结果无显著差异，适合于大批量样品的分析     

木麻黄针叶中矿质元素的快速测定

用原子吸收分光光度计对１．５ｍｏｌ．Ｌ＾－１盐酸浸提木麻黄针叶中钠、钙、镁等矿质元素进行测定，具有快速简单、容易操作，减少污染等特点，实验结果表明：用该方法测定木麻黄针叶中钠、钙、镁等矿质元素，变异系数小，回收率高，具有较高的精密度和较好的重现性。与国家标准法：硫酸－高氯酸湿灰化法比较测定结果无显著差异，适合于大批量样品的分析。     

思茅松树皮多聚原花青素降解优化（英文）

【目的】以基于茶多酚的思茅松树皮多聚原花青素降解反应中(-)-表儿茶素-(4β-8)-(-)-表没食子儿茶素3-O-没食子酸酯(化合物1)的含量作为评价指标,确定思茅松树皮多聚原花青素的最佳降解条件,为思茅松树皮多聚原花青素降解产物的进一步开发利用提供基础。【方法】采用HPLC定量分析方法测定各反应溶液中化合物1的含量,通过单因素试验考察反应温度(50~90℃)、反应时间(30~180 min)、盐酸浓度(0.1%~5%)和茶多酚/多聚原花青素比率(1∶3~3∶1,w/w)对化合物1生成的影响。采用4因素5水平中心组合旋转设计的响应面法优化其降解条件,以化合物1的含量为响应值,以上述4个因素为自变量,利用Design-Expert V8.0.6软件对28个试验点测定所得数据进行多元非线性分析,建立回归模型,并通过方差分析对模型进行显著性检测。【结果】反应温度、盐酸浓度和茶多酚/多聚原花青素比率明显影响降解反应中化合物1的生成,建立的回归模型极显著(P0.000 1),且线性系数良好(R2=0.952 6),说明建立的数学模型能较好地描述试验结果,可用于分析和预测化合物1的生成。思茅松树皮多聚原花青素的最佳降解条件为反应温度70℃、反应时间60 min、盐酸浓度1%和茶多酚/多聚原花青素比率3∶2。经验证此条件下反应液中化合物1的浓度可达718.57 nmol·mL~(-1),与理论值(721.39 nmol·mL~(-1))较为接近。【结论】采用中心组合旋转设计的响应面法分析优化思茅松树皮多聚原花青素降解以获取主产物(-)-表儿茶素-(4β-8)-(-)-表没食子儿茶素3-O-没食子酸酯的方法可行。     

大血藤原花色素抗氧化活性及酶抑制活性研究

用70%乙醇从大血藤中提取原花色素,并对粗提物进行纯化和分离,采用香草醛-盐酸比色法测定各样品中原花色素含量,并测定各样品抗氧化活性和酶抑制活性。结果表明:大血藤乙醇粗提物(CE)、石油醚萃取物(PE)、乙酸乙酯与水两相不溶物(EIF)、乙酸乙酯萃取物(EF)、正丁醇萃取物(BF)和水相留余物(WR)中含原花色素分别为(36.03±0.40)%、(1.19±0.11)%、(57.99±0.22)%、(32.40±0.07)%、(25.03±0.08)%和(41.32±0.37)%。大血藤乙醇粗提物经葡聚糖凝胶LH-20纯化后,含原花色素(98.35±0.72)%,约为粗提物的2.73倍;大血藤纯化物(PT)对二苯基苦基肼自由基(DPPH·)的半数抑制质量浓度(IC_(50))为(70.70±1.38)mg/L,是L-抗坏血酸的1.12倍;对α-葡萄糖苷酶的IC_(50)为(4.37±0.17)mg/L是阿卡波糖的120.71倍。说明大血藤含有丰富的原花色素,大血藤原花色素具有较强的体外抗氧化活性和酶抑制活性。     

木质素模型化合物香草醛Mannich反应及其产物化学结构表征

以木质素模型化合物香草醛、二乙醇胺及多聚甲醛为原料,1,4-二氧杂环己烷为溶剂,通过Mannich反应合成了香草醛胺基多元醇,研究了物料配比、反应温度、时间及溶剂用量等因素对Mannich反应的影响。实验结果表明:反应物料按物质的量比n(香草醛)∶n(甲醛)∶n(二乙醇胺)1∶1∶1,甲醛与二乙醇胺60℃反应2 h生成1,3-氧氮杂环戊烷,再将其滴入香草醛中,80℃反应3 h,二氧六环溶剂用量为100 mL/mol(以香草醛的物质的量计),二乙醇胺的转化率最高可达到84.92%。采用HPLC、LC-MS、FT-IR及1H NMR表征了香草醛胺基多元醇的化学结构,相对分子质量269。     

杜仲叶酸性多糖提取分离及含量测定

研究杜仲叶酸性多糖的提取分离工艺及其含量测定的简便方法.结果表明,以提取过药用有效成分后的杜仲叶为原料提取酸性多糖的较佳工艺条件是:1.0%的碱水在100 ℃下提取2次,每次2 h;提取液经大孔吸附树脂处理,多次醇沉等步骤分离的酸性多糖含量可达到41.46%.采用DNS法测定杜仲叶酸性多糖含量时水解时间控制在15～20 min,显色反应为10 min,检测波长为492 nm;在试验条件下,葡萄糖浓度在0.20～0.60 mg·mL-1范围内显色灵敏、稳定,线性关系良好;用该法测定杜仲叶渣酸性多糖含量时加样回收率为98.30%,RSD为1.76%;显色溶液在2 h内吸光度值比较稳定,能够完全满足测定工作要求,可以作为实验室测定多糖含量的简便、快捷、有效的方法.     

人造板制品中三甲胺的检测方法研究

建立人造板中三甲胺的顶空气质联用检测方法,样品经盐酸溶液提取后,在氢氧化钠溶液作用下转化为三甲胺,顶空进样检测,SIM模式外标法定量。结果显示:三甲胺在质量浓度范围0.1~5mg/kg呈良好的线性关系(R^2=0.9994),样品加标的平均回收率为94.5%~101.2%,相对标准偏差为2.11%(n=6)。该法具有较高的精密度,回收率和重现性良好,适用于人造板制品中三甲胺的测定。     

七叶莲总皂苷定量分析方法及其提取工艺研究

以齐墩果酸为对照品,建立了比色法测定七叶莲总皂苷含量的方法;以总皂苷得率为指标,采用正交试验法对七叶莲总皂苷提取工艺进行了优化.结果表明:在比色法定量分析时,以5%香草醛冰醋酸溶液-高氯酸为显色剂,70℃加热15min显色后,选择546nm为测定波长,在40min内,测量结果稳定,总皂苷质量浓度在0.002~0.02g/L范围内呈良好的线性关系(r=0.99933);平均加样回收率为101.2%,相对标准偏差(RSD)为0.86%(n=6).在提取过程中,优化的工艺参数为:以50%(体积分数)乙醇为溶剂,控制固液比1∶15(g∶mL),80℃水浴提取2次,每次120min,此条件下总皂苷得率1.217%.     

全自动索氏提取-气相色谱三重四极杆串联质谱法测定土壤中18种多环芳烃

建立了全自动索氏提取-气相色谱三重四极杆串联质谱法测定土壤中18种多环芳烃的分析方法。土壤经正己烷和乙酸乙酯(1∶1v/v)提取后,硅胶小柱净化,外标法定量。方法对土壤前处理和仪器条件进行了优化,实际测定结果表明:18种多环芳烃含量在2～50μg/L间呈良好的线性关系,相关系数r2均大于0.997;添加0.05～0.50mg/kg浓度,平均回收率在80.2%～92.4%,相对标准偏差(RSD)为3.2%～8.9%,该方法的灵敏度、准确度和精密度均符合测定的技术要求。     

An early gene of the flavonoid pathway, flavanone 3-hydroxylase, exhibits a positive relationship with the concentration of catechins in tea (Camellia sinensis)

Tea (Camellia sinensis (L.) O. Kuntze) leaves are a major source of flavonoids that mainly belong to the flavan 3-ols or catechins. Apart from being responsible for tea quality, these compounds have medicinal properties. Flavanone 3-hydroxylase (F3H) is an abundant enzyme in tea leaves that catalyzes the stereospecific hydroxylation of (2S)-naringenin to form (2R,3R)-dihydrokaempferol. We report a full-length cDNA sequence of F3H from tea (CsF3H Accession no. AY641730). CsF3H comprised 1365 bp with an open reading frame of 1107 nt (from 43 to 1149) encoding a polypeptide of 368 amino acids. Expression of CsF3H in an expression vector in Escherichia coli yielded a functional protein with a specific activity of 32 nmol min(-1) mg protein(-1). There was a positive correlation between the concentration of catechins and CsF3H expression in leaves of different developmental stages. CsF3H expression was down-regulated in response to drought, abscisic acid and gibberellic acid treatment, but up-regulated in response to wounding. The concentration of catechins paralleled the expression data. Exposure of tea shoots to 50-100 microM catechins led to down-regulation of CsF3H expression suggesting substrate mediated feedback regulation of the gene. The strong correlation between the concentration of catechins and CsF3H expression indicates a critical role of F3H in catechin biosynthesis.     

Reactivity of green tea catechins with formaldehyde

In the reaction of green tea catechins with formaldehyde at room temperature (25°C), tea catechins were found to have reactivity. In particular, (-)-epicatechin gallate and (-)-epigallocatechin gallate, which have a galloyl moiety at the C-3 position, showed higher reactivity than (+)-catechin, (-)-epicatechin, or (-)-epigallocatechin. Reactivity of various kinds of simple phenolic compounds and flavonoids with formaldehyde was also examined. Among these compounds, only phloroglucinol showed reactivity to the same degree as that of nongalloylated catechins. These results suggest that factors for reactivity with formaldehyde at room temperature may be the presence of a phloroglucinolic A-ring structure and the absence of the electron-attractive group such as a carbonyl group in Cring. The comparison of the reactivity of 3-O-acylated catechins with that of 3-O-galloylated catechins indicated that only a galloyl group effectively enhanced reactivity with formaldehyde.     

"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。     

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。     

Localization and quantitative determination of catechins and proanthocyanidins in the phloem of elm and cherry

The localization of catechins and proanthocyanidins in the phloem of elm (Ulmus minor Mill.) and cherry (Prunus avium L.) was determined histochemically by use of 4-dimethylaminocinnamaldehyde (DMACA) reagent. The two tree species showed a characteristic distribution of these phenols, which were most abundant in the phloem rays of cherry, but were largely confined to upright parenchyma cells of elm. Quantitative determination and qualitative separation of catechins and proanthocyanidins were performed using HPLC-CRD (chemical reaction detection), with 4-dimethylaminocinnamaldehyde as the staining reagent. Up to 14 different catechins and proanthocyanidins were found in both species.     

浙江山区茶园茶叶氟含量及影响因素

氟是人体必需的微量元素之一,它在人体生长发育和骨骼代谢中起着重要作用,摄入适量的氟有益于身体健康.但是过量摄入会导致慢性氟中毒,主要表现为氟斑牙和氟骨症等.茶树(Camellia sinensis)对土壤和环境中氟具有较强富集作用,所以茶叶中氟含量状况以及饮茶是否会摄入过量氟等问题为社会所关注(孙殿军等,2005).     

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.     

山杏叶桦木酸、齐墩果酸和熊果酸的研究

我国山杏资源十分丰富,是绿化荒山的优良树种。采用HydersirBDSC18色谱柱（150×4．6mm,5μm）,流动相体积比为90：10的0．3‰硫酸甲醇溶液一3‰硫酸水溶液,检测波长210nm,建立了山杏叶中三萜酸测定的高效液相色谱法。结果表明：桦木酸、齐墩果酸与熊果酸的浓度在30～2000μg／mL（r桦=0．9971,r齐=0．9986,r熊=0．9978）范围内与色谱峰面积呈良好线性关系;平均加标回收率分别为99．9％、101．1％和98．9％。以山杏叶为材料,采用高效液相色谱法和紫外可见分光光度法分别对山杏叶中的三萜酸成分进行分析,结果表明,山杏叶富含三萜酸,落叶期山杏叶中总三萜酸（17078#g／g）、桦木酸（1842μg／g）、齐墩果酸（2536μg／g）和熊果酸（5706μg／g）含量均高于非落叶期。本研究首次建立了山杏叶中桦木酸、齐墩果酸和熊果酸同时测定的反向高效液相色谱法（HPLC）,发现落叶期山杏叶富含三萜酸,为山杏叶综合开发利用提供了基础数据。     

苗圃灰色潮土大团聚体粒级的氮素分布特性

本文对苗圃灰色潮土大团聚体进行分析表明:水稳性团聚体含量为47.55％。水稳性团聚体各粒级上的有机质与相应粒级上的全氮含量呈极显著的线性相关(F=38.81>F_(0.01)=21.2),而与相应粒级上的水解性氮之间无显著相关性。     

竹炭对苯胺吸附的热力学与动力学研究

从热力学和动力学角度，研究了竹炭对水中苯胺的吸附行为。动力学研究表明：竹炭对苯胺的吸附拟用准一级动力学描述，动力学方程可表示为-In（1-F）=kt。表观吸附速率常数与温度的关系符合Arrhenius经验公式，测得其表观活化能约为29．4kJ／mol。热力学研究表明：温度升高，吸附平衡常数减小，吸附量减小。竹炭对苯胺吸附的焓变为负值，说明竹炭吸附过程为放热过程，且AH〈40kJ／mol，表明吸附过程主要为物理吸附。测得吉布斯自由能AG〈0，表明吸附质从溶液到吸附刺表面的吸附过程是自发过程。