番石榴叶乙酸乙酯萃取物的体外抗氧化活性及化学成分的分离鉴定

本文研究了番石榴叶乙酸乙酯萃取物的体外抗氧化活性及活性物质基础。采用95%乙醇溶液浸泡提取、正己烷和乙酸乙酯萃取后得到粗提物,首先分析了乙酸乙酯萃取物的体外抗氧化活性,然后通过硅胶柱色谱、Sephadex LH-20凝胶柱色谱、质谱和核磁共振等技术对乙酸乙酯萃取物的化学成分进行了分离和鉴定。结果表明,乙酸乙酯萃取物对DPPH自由基、超氧阴离子、羟自由基具有较强的体外抗氧化活性,清除能力随着浓度的增大而增强,当浓度为1 mg/m L时,对DPPH自由基、超氧阴离子和羟自由基的清除率分别达94.15%、87.88%和67.3%,清除效果接近或强于同浓度的Vc。通过硅胶柱色普、Sephadex LH-20凝胶柱色谱等技术从番石榴叶乙酸乙酯萃取部位中分离纯化得到5个化合物,通过MS和NMR等波谱数据和结合文献,最终确定了4个化合物,分别为:去甲氧基荚果蕨(1)、胶藤素(2)、槲皮素(3)和异槲皮苷(4),其中化合物2为首次从番石榴属植物中分离得到的二氢黄酮类化合物。     

接骨木叶黄酮提取工艺及体外抗氧化活性研究

在单因素实验的基础上,采用响应面法对接骨木叶片总黄酮的超声辅助提取工艺进行了优化,并对接骨木叶片总黄酮乙醇提取物的乙酸乙酯、氯仿、正丁醇、水四种不同极性溶剂分级萃取组分的抗氧化活性进行了分析。结果表明:超声辅助提取接骨木叶片总黄酮的最佳工艺条件为:乙醇浓度70%,料液比1∶40,提取温度70℃,提取时间60 min,在此条件下,总黄酮最高提取得率可达18.67%;乙酸乙酯、氯仿、正丁醇、水四种极性萃取组分中黄酮相对含量分别为54.3%、28.22%、22.01%、9.817%,且四种组分对DPPH自由基和ABTS+自由基均有一定的清除活性,但均以乙酸乙酯萃取组分的清除活性最高,说明接骨木叶片乙酸乙酯萃取组分富含天然抗氧化剂,具有潜在的开发价值。     

育发类化妆品中斑蝥素的含量测定

建立用乙酸乙酯作为萃取剂的育发类化妆品中斑蝥素的含量气相测定方法。以乙酸乙酯为萃取剂,利用漩涡振荡器振摇提取,离心分离,气相色谱测定斑蝥素含量。结果表明：斑蝥素在0.0005~0.0031mg/ml之间线性关系良好,r=0.9960,回收率为96.0%,RSD为1.3%（n=6）。该方法操作准确、简单、分离好,安全可以作为育发类化妆品中斑蝥素含量的测定。     

玫瑰花总黄酮微波辅助提取及其抗氧化研究

采用微波辅助提取的方法提取玫瑰花中的总黄酮,并对提取的黄酮进行了抗氧化测定。结果表明:玫瑰花总黄酮含量为2.2%,最佳提取工艺条件为提取温度65℃、料液比1∶55、乙醇浓度65%、微波时间45min、微波功率700W,提取率为82.29%。清除DPPH·实验测得玫瑰花黄酮的乙酸乙酯、正丁醇、水萃取物的IC50分别为6.52、9.04、6.87μg/mL;清除O2-.实验测得在萃取物浓度为100μg/mL时,乙酸乙酯、正丁醇、水萃取物对O2-·的抑制率分别为14.43%、27.83%、23.21%;清除.OH的实验测得在萃取物浓度为500μg/mL时,乙酸乙酯、正丁醇、水萃取物对.OH的抑制率分别为23.74%、43.51%、32.75%。实验得到结论为玫瑰花中的黄酮类化合物具有一定的抗氧化活性。     

核桃粕中环烯醚萜苷提取分离与抗疲劳活性研究

核桃粕经乙醇提取,乙酸乙酯、正丁醇分别萃取,不同溶剂萃取物通过小鼠跑台试验和负重游泳试验确定抗疲劳作用,并对有明确抗疲劳效果的萃取物进行MCI分离柱、ODS反相柱层析分离,得到的单体化合物采用核磁共振法鉴定其结构。结果表明:核桃粕醇提物正丁醇萃取物抗疲劳作用效果最为明显,该部分上ODS柱经5%乙醇洗脱分离得化合物Ⅱ,鉴定得该化合物为4-羧基-7-羟基-8-乙酸乙酯基-3,6-环戊烯环烯醚萜苷,且能显著提高小鼠运动抗疲劳能力。     

翻白草活性成分的萃取

以翻白草全草为实验材料,用70%的乙醇为溶剂,采用超声波环流提取方法对翻白草进行粗提取,再用石油醚、乙酸乙酯、正丁醇依次对提取液进行萃取,减压干燥得到提取产物.测定萃取产物黄酮的含量,结果显示,用乙酸乙酯萃取翻白草活性成分效果最好.     

用茶末及废茶枝叶提取高纯茶多酚的研究

本文研究了以茶末和废枝叶为原料提取茶多酚的工艺。工艺流程为:(1)原料经微沸水浸提后加入碳酸氢铵调pH至中偏酸性后用硫酸锌沉淀纯化;(2)然后用硫酸解析溶解沉淀,加入乙酸乙酯进行萃取,分相后,水相(硫酸锌溶液)循环供沉淀纯化用,有机相(乙酸乙酯 茶多酚)真空分离、干燥制取高纯茶多酚,萃取剂乙酸乙酯回收循环使用;茶末、废茶枝叶和碳酸氢铵、硫酸进行茶多酚的浸提和纯化后,以有机多元复肥形式回收综合利用。茶多酚的综合提取率大于13%,质量达到GTP-l(大于95%)要求。     

月见草籽粕中抗氧化活性物质的研究

利用超声波辅助提取法对月见草籽粕中的抗氧化活性物质进行提取,再依次用石油醚、二氯甲烷、乙酸乙酯、正丁醇进行萃取分离。采用比色法测定各萃取物对DPPH·、O-2·、·OH 3种自由基的清除作用以及总还原力。结果表明:月见草籽粕乙酸乙酯萃取物对3种自由基具有明显的清除作用,对Fe3+也有较强的还原能力。对月见草籽粕乙酸乙酯部位进行显色反应,初步鉴定抗氧化活性物质为黄酮类物质。经聚酰胺柱色谱法和葡聚糖凝胶柱分离纯化及LC-MS鉴定,该活性物质为槲皮素和山奈酚。     

古尼虫草菌丝体维生素E的初步分析

古尼虫草与传统名贵中药冬虫夏草类似,具有多种活性物质及广泛的药理作用,是一种重要的虫草属真菌.分别用30 %、50 %、80 %乙醇溶液和乙酸乙酯作为提取液,从古尼虫草菌丝体中提取维生素E,并用乙酸乙酯萃取的方法进行初步分离,硅胶薄层层析和紫外分光光度法分析粗产物中的维生素E.结果表明,提取物质的总量与提取液的乙醇含量有关,提取液的有机溶剂比例越高,提取到维生素E量越高,但提取的维生素E的纯度越低.初步确定乙酸乙酯为提取虫草维生素E的最适溶剂.     

高速逆流色谱法分离纯化杜仲叶中绿原酸

目的:建立高速逆流色谱(HSCCC)法从杜仲叶中分离纯化绿原酸。方法:将杜仲叶用50%乙醇提取,乙酸乙酯萃取,减压浓缩得粗提物,绿原酸含量为16.15%,再进行HSCCC分离纯化。用HPLC考察了绿原酸在不同溶剂体系中的分配情况,选择正丁醇-乙酸乙酯-水(3∶1∶4)为HSCCC为溶剂体系,上相为固定相,下相为流动相,主机转速850r/min,流速2m L/min,检测波长327nm。结果:从100mg杜仲粗提物中分离到8.27mg绿原酸,经HPLC分析绿原酸质量分数为86.20%,紫外、红外光谱扫描与对照品特征峰一致。结论 HSCCC法可用于杜仲叶中高纯度的绿原酸快速分离纯化。     

微波技术在茶叶加工中的应用

简介微波工作原理，综述微波技术在茶叶加工的杀青工序、辅助萃取茶多酚、咖啡碱、茶多糖等药效成分、干燥工序以及在测定茶叶中农药和重金属残留中的应用。     

超声波辅助提取桦褐孔菌子实体中多糖和三萜

研究了优化超声辅助提取桦褐孔菌中多糖和三萜类物质的工艺。以蒸馏水和异丙醇为提取剂,用超声波辅助提取桦褐孔菌多糖和三萜类物质,以不同处理条件、超声功率、超声次数、超声处理时间为试验因素,以多糖和三萜的提取率为考察指标进行单因素实验确定最佳提取工艺。超声辅助技术提取桦褐孔菌子实体中多糖类和三萜类物质的最佳工艺条件为:超声功率400 W、超声20次、超声10 min,在此条件下多糖得率最高,为11.62%,总三萜类物质得率在2%,使得多糖和三萜类物质二者共提取得率达到13.57%。     

绿茶萃取物溶出变化研究

研究绿茶在50、60、70、80℃水中不同时段萃取时萃出液中茶多酚(EG、EGC、ECG、GGEG)、氨基酸、果胶等的变化。结果显示,游离型儿茶素在冷水中比较容易溶出,3萃时有80%～90%溶出;酯型儿茶素的溶出较慢,3萃时只有50%左右溶出;咖啡因的溶出特性与游离型儿茶素相类似;氨基酸在1萃溶出量较多,从1萃到3萃前,依次下降,除精氨酸外,其他氨基酸在2萃时溶出率达70%～80%,3萃时溶出率为90%～100%,精氨酸在2萃时溶出率为50%,3萃溶出率为70%;钙、镁、磷酸类在1～3萃取中溶出量依次降低;1萃时水溶及盐溶性果胶的萃取率较高。以上参数为茶饮料的工业化生产及品质保证提供参考。     

Extraction of active ingredients from green tea (Camellia sinensis): Extraction efficiency of major catechins and caffeine

The effect of different extraction set-ups that influence the extraction efficiency of catechins and caffeine from green tea leaves (variety Fanning Belas, China) were studied using different aqueous and pure solvents (acetone, ethanol, methanol, acetonitrile, water), different temperatures (60, 80, 95 and 100 °C) and times (5–240 min). Raw extracts were analysed for contents of major catechins (EC, EGC, ECG, EGCG), caffeine, proanthocyanidins and flavonols (myricetin, caempherol, quercetin). Starting material was found to contain 191 g major catechins/kg material, 36 g caffeine/kg material and 5.2 g flavonols/kg material on a dry mass basis. The content of major catechins in green tea extracts varied from approximately 280–580 g/kg dry extract, with extraction efficiencies of major catechins varying from 61% to almost 100%. Content of caffeine in extract was in the range of 75 g/kg, where its extraction efficiency varied from 62% to 76%. Average extraction yield was 30% with exceptions when using pure acetone and acetonitrile, where extraction yield was about 3%. Contents of flavonols and proanthocyanidins were in the ranges 6–20 and 12–19 g/kg, respectively. Different extraction procedures with water were also investigated and optimal conditions determined: maximum achieved extraction efficiency of catechins with water was obtained at 80 °C after 20 min (97%) and at 95 °C after 10 min of extraction (90%). Degradation of catechins was observed at higher extraction temperatures and with prolonged extraction times. Using a lower ratio of solvent to material, extraction efficiencies were increased by applying a multi-step extraction procedure. Optimal extraction procedure was then performed using decaffeinated green tea leaves, which were obtained by high-pressure extraction with CO₂, when 98% of caffeine was selectively isolated without significant impact on valuable catechins.     

超高效液相-串联质谱法研究银杏叶提取物提取过程中咖啡因的转移规律

目的:研究银杏叶提取物提取过程中咖啡因的转移规律,采用超高效液相色谱-串联质谱法测定咖啡因含量。方法:色谱柱为ACQUITY UPLC BEH C18(2.1 mm×50 mm,2.7 μm),流动相采用0.1%甲酸溶液和0.1%甲酸乙腈溶液梯度洗脱进行,流速0.3 mL/min,进样量5 μL,柱温30℃,运行时间5 min。质谱参数采用电喷雾离子源(ESI),检测方式采用多反应监测和正离子模式扫描,并进行定量分析。结果:通过优化检测方法,加标回收率在95.23%~102.49%之间,检出限为5 μg/kg,定量限为15 μg/kg。结论:建立的超高效液相色谱-串联质谱检测咖啡因含量方法操作简便,灵敏度高。研究发现,银杏叶中天然存在咖啡因,且不同产地银杏叶中咖啡因含量不同,可能和银杏生长的气候和地域有关系。银杏叶提取生产加工时,原料中约35%的咖啡因会转移至提取物中。     

超临界CO2脱除茶叶咖啡碱的工艺优化研究

本文在大量实验基础上,研究了超临界CO2脱除茶叶中咖啡碱的工艺条件优化,着重讨论了影响咖啡碱脱除率的因素及茶叶风味的保存因素,结合产品质量分析,得到了预脱茶香和脱咖啡碱的两级萃取、茶香吸附和咖啡碱解析的两路分离、加稀乙醇作夹带剂的最佳工艺路线及参数,达到既保持了茶叶特别香味,又能有效脱除茶叶中咖啡碱的目的。     

低咖啡因茶氨酸产品的精制工艺研究

研究以茶氨酸粗品为原料,采用树脂吸附法脱除咖啡因,溶剂萃取法和重结晶法进一步纯化茶氨酸,生产低咖啡因的高含量茶氨酸产品。结果表明,HPD-4大孔树脂能够有效吸附咖啡因,茶氨酸物料经HPD-4树脂1BV/h速度吸附后,纯水1BV/h速度洗脱1h,可得到几乎不含咖啡因的茶氨酸产品,同时产品中茶氨酸含量提高了50%,回收率83%以上。常规溶剂萃取对茶氨酸选择性较差,不能有效纯化茶氨酸;而3次重结晶可使茶氨酸含量再提高1倍以上。     

真空升华法脱除绿茶中咖啡碱工艺研究

根据咖啡碱升华的理化性质,本文采用真空升华法脱除炒青绿茶中的咖啡碱,并研究了其最佳工艺参数及此工艺对炒青绿茶品质的影响。结果表明,茶样中的咖啡碱处于结合态,不易升华,所以直接对茶样进行真空升华处理,茶样中咖啡碱的脱除率未超过15%。研究不同预处理对咖啡碱脱除效果的影响,发现水浸润预处理结合超声-微波协同萃取仪预处理,对咖啡碱的脱除最为有效。真空升华最佳工艺为:将茶样用2倍于其质量的水浸润后,采用超声-微波协同萃取仪在微波功率300W、超声功率50W条件下处理60s后在90℃条件下真空升华处理4h,所得茶样咖啡碱脱除率为62.24%,主要有效成分茶多酚损失率低于10%,且非酯型儿茶素的损失量大于酯型儿茶素。     

Column-chromatographic extraction and separation of polyphenols, caffeine and theanine from green tea

A highly efficient column-chromatographic extraction (CCE) followed by sequential adsorption to extract and separate bioactive compounds from green tea was developed. Tea powder was loaded into columns with 4-fold solvents and eluted through a cyclic CCE. High-quality tea extracts with greater than 90% extraction efficiencies of polyphenols, epigallocatechin-3-gallate, caffeine, theanine and polysaccharides were obtained with 4-fold water circulated five times among different columns at 70 °C. Similar results, except for low polysaccharide extraction (35.5%), were obtained with 4-fold 30% ethanol circulated three times at room temperature. The highly concentrated water extraction was directly passed through columns of polyamide, DM130 macroporous and 732 ion exchange resins, resulting in high-purity polyphenols (99%), caffeine (98%) and theanine (98%) after simple purification of the eluates from each column. This method uses simple equipment, minimum solvents and can be used for both quantitative analysis and continuous preparation of high-quality tea extracts and bioactive compounds.     

Solid–liquid extraction of caffeine from tea waste using battery type extractor: Process optimization

This article deals with solid–liquid extraction of caffeine from tea waste containing 2% (w/w) caffeine using water and chloroform as effective solvents. The extraction has been performed at isothermal conditions of 370 K for water and 293 K for chloroform in the battery type extraction plant including both three and five extractors connected in series. An obvious difference in extraction behavior has been observed for two solvents, distinguishing the divergent interactions attributed to the different mechanism of solvent–caffeine aggregation. The high degree of separation of caffeine by chloroform is feasible with the efficiency ranging about two times larger than water in terms of the solvent flow rates tested. The optimum process parameters were estimated through the graphical interpretation of dependently changing variables, composition, flow rate and extraction degree. Details underlying some aspect of selection of an appropriate differential equation for fitting the data are discussed.