碘量法测定黄花蒿中青蒿素含量

为了快速简便准确测定黄花蒿中青蒿素含量,利用碘量法建立一种青蒿素的测定方法。使用间接碘量法,以淀粉为指示剂,硫代硫酸钠为滴定剂,测定黄花蒿的石油醚提取液中青蒿素含量。通过稳定性、重现性、线性关系考察和加样回收率等指标考察方法的可行性。碘量法测定黄花蒿中青蒿素含量具有良好的线性关系,重现性、稳定性和加样回收率满足分析要求。     

Microwave-Assisted Batch Extraction of Polyphenols from Sea Buckthorn Leaves

Extraction of polyphenols from sea buckthorn leaves using microwave-assisted extraction (MAE) is described. The influence of different parameters on the extraction process (reactor type, stirring rate, extraction time, temperature, ethanol/water ratio) was studied. The polyphenolic extracts were analyzed in order to determine the total phenolic content (TPC) either by the Folin–Ciocalteu method or by differential pulse voltammetry (DPV), and the concentration of the main polyphenolic compounds by high-performance liquid chromatography (HPLC). The specific microwave energy was also determined. MAE resulted in a shorter extraction time (7.5 versus 30 min for the conventional method). The best results for MAE were obtained at a temperature of 90°C, using a solvent/plant ratio of 20/1 and 50% ethanol in the extraction solvent. The highest values of antioxidant capacity were obtained for polyphenolic extracts resulted from microwave extraction.     

中药蛇床子中黄酮类成分的研究

介绍了优选蛇床子总黄酮的最佳提取工艺。采用L9（3^3）正交试验，考察乙醇浓度、提取温度及提取时间，以总黄酮含量为评价指标，并采用分光光度法测定吸光度。并对黄酮类成分进行验证，得出蛇床子总黄酮的最佳提取工艺为80％的乙醇提取2次，每次30min，提取温度65℃。优选得到的工艺稳定可行。     

A rapid and quantitative method for total fatty acid analysis of fungi and other biological samples

A quantitative method for the one-step esterification and determination of absolute amounts of polyunsaturated fatty acids in biotechnologically produced fungal mycelia is proposed. A system of two internal standards was used to quantify the total fatty acid content of the samples by gas chromatography. The degree of methylation of the analyzed fatty acids was calculated using the internal standards, and subsequently this quotient was used to validate the derivatization and extraction reactions. By utilizing this degree of methylation, the corrected amounts of the various fatty acids in the sample can be calculated.     

离子液体提取构树叶总黄酮的工艺

以构树叶为研究对象,研究了离子液体苯并噻唑甲烷磺酸盐在总黄酮提取工艺上的应用,采用Al（NO₃）₃-NaNO₂比色法测定了构树叶中总黄酮的含量。通过单因素试验,以构树叶中总黄酮提取率为指标,探讨了离子液体浓度、乙醇体积分数、提取温度、提取时间、料液比对构树叶中总黄酮提取率的影响。实验结果表明在离子液体浓度0.5mol/L、乙醇体积分数60%、提取温度60℃、提取时间20 min、料液比1：20的工艺条件下,测得构树叶总黄酮含量为0.4685mg/g。该提取工艺操作简单、合理、提取效率较高。     

Effect of Different Drying Methods on the Microwave Extraction of Phenolic Components and Antioxidant Activity of Highbush Blueberry Leaves

In the last few decades, researchers have found blueberry leaves to be an interesting source of different phenolic compounds, and drying is an important part of their postharvest and sample preparation processes. In the current study, blueberry leaves were dried using microwave-assisted hot air drying or hot air drying alone at 45, 60, and 75°C to 10–15% wet basis. Corresponding drying characteristics were determined by fitting the moisture ratio obtained in each case with eight theoretical and semitheoretical models for hot air and microwave drying stages. It was observed that best fitting drying models for blueberry leaves depended not only on the nature of the biomaterial but also on the method of drying and the temperature of drying. Phenolic content, monomeric anthocyanin content, and the corresponding antioxidant activity in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition activity and ferric reducing ability of plasma (FRAP) activity were evaluated for the leaf extract obtained following microwave extraction of the dried samples obtained using the above-mentioned drying methods and were compared to the corresponding bioactive compositional characteristics of freeze-dried blueberry leaves. It was observed that the freeze-dried sample had the highest content of total phenolics and total monomeric anthocyanins along with high antioxidant activity. Furthermore, extracts obtained from the microwave-dried leaf samples obtained with a drying temperature of 60°C had highest total phenolic content and highest total monomeric anthocyanin content among all other drying methods and the extract had an antioxidant activity similar to the freeze-dried blueberry leaf samples, implying that microwave drying at 60°C is a potential alternative to freeze drying for preservation of the phenolic components and antioxidant activity of dried blueberry leaves.     

An Improved Method for Separating Cardiolipin by HPLC

Herein we report an improved method to separate cardiolipin (Ptd(2)Gro) from tissue total lipid extracts using a biphasic solvent system combined with high performance liquid chromatography. This method uses a normal phase silica column and two mobile phases: mobile phase A that was n-hexane:2-propanol (3:2 by vol) and mobile phase B that was n-hexane:2-propanol:water (56.7:37.8:5.5 by vol). The initial solvent conditions were 95% A and 5% B, with a flow rate of 1.5 mL/min. The samples were from non-derivatized aliquots of liver, heart, or brain lipid extracts. The peak corresponding to Ptd(2)Gro appeared at 31 min, was well defined and did not overlap with neighboring peaks. The adjacent peak corresponded to ethanolamine glycerophospholipids and the remaining phospholipids were eluted in a single peak. The identity of the phospholipids separated by this method was verified by thin layer chromatography (TLC) and fatty acid analysis, which confirmed that the Ptd(2)Gro was well resolved from other phospholipids. This method is useful to separate and quantify Ptd(2)Gro from small tissue samples thereby avoiding the variability associated with TLC methods.     

Selection of Direct Transesterification as the Preferred Method for Assay of Fatty Acid Content of Microalgae

Assays for total lipid content in microalgae are usually based on the Folch or the Bligh and Dyer methods of solvent extraction followed by quantification either gravimetrically or by chromatography. Direct transesterification (DT) is a method of converting saponifiable lipids in situ directly to fatty acid methyl esters which can be quantified by gas chromatography (GC). This eliminates the extraction step and results in a rapid, one-step procedure applicable to small samples. This study compared the effectiveness of DT in quantifying the total fatty acid content in three species of microalgae to extraction using the Folch, the Bligh and Dyer and the Smedes and Askland methods, followed by transesterification and GC. The use of two catalysts in sequence, as well as the effect of reaction water content on the efficiency of DT were investigated. The Folch method was the most effective of the extraction methods tested, but comparison with DT illustrated that all extraction methods were incomplete. Higher levels of fatty acid in the cells were obtained with DT in comparison with the extraction-transesterification methods. A combination of acidic and basic transesterification catalysts was more effective than each individually when the sample contained water. The two-catalyst reaction was insensitive to water up to 10% of total reaction volume. DT proved a convenient and more accurate method than the extraction techniques for quantifying total fatty acid content in microalgae.     

Optimizing Microwave‐Assisted Extraction Conditions to Obtain Phenolic‐Rich Extract from Chromolaena odorata Leaves

Phenolic compounds are secondary metabolites that are mainly responsible for different pharmacological activities of plant extracts. In this study, microwave‐assisted extraction (MAE) variables were optimized for the extraction of phenolic compounds from Chromolaena odorata leaves by using a Box‐Behnken design of response surface methodology. The concentration of polyphenols and functional characteristics of the extracts were identified by using liquid chromatography quadrupolar time‐of‐flight mass spectrometry and FTIR analyses, respectively. The obtained results indicated the MAE conditions for the optimal recoveries of the total phenolic content and total flavonoid content from C. odorata leaves. The results reveal that the C. odorata leaf is enriched with phenolic compounds.     

超声强化溴化1-乙基-3-甲基咪唑从黄花蒿中提取青蒿素

利用超声强化[emim]Br(溴化1-乙基-3-甲基咪唑)-水体系从黄花蒿粉末中提取青蒿素. 正交实验和单因素实验结果表明,影响黄花蒿中青蒿素提取因素的显著性次序为液固比>提取时间>提取温度>超声波功率>占空比. 综合考虑单因素实验结果及成本,得出优化工艺条件为黄花蒿原料粒度0.38 mm,液固比50 mL/g,提取时间30 min,提取温度20℃,超声波功率600 W,占空比1.6 s/0.4 s. 在上述条件下青蒿素提取量为4.37 mg/g,提取率为97%.     

Rapid Separating and Enrichment of 4,4′-Dimethylsterols of Vegetable Oils by Solid-Phase Extraction

Phytosterols are separated into three classes: 4-desmethylsterols, 4-monomethylsterols and 4,4′-dimethylsterols. 4,4′-Dimethylsterols are used to detect vegetable oil adulteration and some compounds from this class can have anti-inflammatory and anticancer properties. There are methods such as thin layer chromatography (TLC) and solid phase extraction (SPE) used to separate phytosterol classes from each other. However, in some cases, separation of all three classes is not required. In addition, TLC has some drawbacks such as low recovery and it is time consuming. An SPE method has previously been used, but it was necessary to use high volume of solvents with this method to avoid coelution of phytosterol classes. In this study, an SPE (silica, 1 g) method was developed to separate and enrich only 4,4′-dimethylsterols from unsaponifiables of vegetable oil samples using 25 mL n-hexane and diethyl ether (95:5, v:v). This method was applied to hazelnut and olive oils and results were compared with those of TLC and the previously developed SPE method. Recovery of 4,4′-dimethylsterols was two times higher with the new SPE method compared with the TLC method. The newly developed SPE method generally gave a similar recovery compared with the previously developed SPE method. Moreover, the SPE method developed in this study has the advantage of using a 3.5 times lower volume of solvent than previously developed SPE methods. Because the newly developed SPE method has a single step requiring a low volume of solvents, it is rapid and simple, and can easily be used to detect olive oil adulteration with hazelnut oil and to analyze and quantify effective nutritional compounds in the 4,4′-dimethylsterols class.     

中药固废原料特性与热解失重特性关联性分析

为了了解中药渣热解特性与组成结构的关联,本研究以10种典型植物类中药渣样品为原料,分析了其组成结构以及有机组分,并采用热重分析仪研究其热解失重特性,通过对中药渣原料特性与热解过程行为进行关联性分析,探讨影响中药渣热解过程的物性因素以及关联耦合机制。研究结果表明：中药渣均检出较高含量的N、S,根类样品的纤维素含量较高,叶类样品的木质素含量较高。叶类、茎秆类以及种子类中药渣样品热解脱挥发分能力较差,采用Coats-Redfern积分法得到热解活化能基本在100 kJ/mol以内;而块根类中药渣样品热解脱挥发分能力较强,活化能高于110 kJ/mol。其中,山药样品热解脱挥发分能力最强,热解活化能为169.83 kJ/mol;青蒿叶样品热解活化能最低,仅64.32 kJ/mol。纤维素和木质素是影响热解脱挥发分和热解活化能的主要物性因素,纤维素和木质素含量可用于预测中药渣热解脱挥发分能力与热解活化能。     

One-step extraction/methylation method for determining the fatty acid composition of processed foods

In a one-step extraction/methylation (OSM) method for determining individual fatty acids (FA) in processed food products, freeze-dried samples, containing 10–50 mg fat, were transmethylated without prior fat extraction with a mixture of methanol-HCl/toluene. After washing the organic phase the formed FA methyl esters were ready for separation by gas-liquid chromatography (GLC). The relative standard deviation for total FA content was <3.5%, regardless of the food type analyzed. Furthermore, the FA composition of selected fatty foods as obtained by the OSM procedure was almost identical with the FA composition of the pure fats extracted by the Soxhlet procedure and with chloroform-methanol, respectively. The OSM method is inexpensive and simple to perform and is, therefore, well suited for nutrient labeling studies, especially in situations where many samples have to be analyzed for their total FA content.     

Isolation and characterization of sucrose polyesters

Various chromatographic techniques for isolation and separation of highly esterified sucrose polyesters (SPE) of olive oil are described. High-performance size-exclusion chromatography was used to check the purity of the samples, particularly to show that SPE were free from unreacted fatty acid methyl esters. Thin-layer chromatography (TLC), Iatroscan TLC flame-ionization detection (FID) and highperformance liquid chromatography (HPLC) on reversed-phase were applied for separation of octa-, hepta- and hexaesters of sucrose. Pure fractions from the total mixture, obtained by column chromatography, were identified by infrared and nuclear magnetic resonance spectroscopy. When necessary, specific reactions were applied; particularly, silylation and lead acetate-dichlorofluorescein (in toluene) spray were used to ascertain the degee of esterification of sucrose. Finally, octa-, hepta- and hexaesters of sucrose were quantitated by silica column chromatography, TLC/FID and HPLC on reversed-phase.     

超高压提取刺五加叶中总黄酮的研究

研究了从刺五加叶中超高压提取总黄酮的工艺条件。通过单因素试验确定了各影响因素的较优水平范围,在此基础上采用均匀设计方法进一步优化出最优提取工艺参数为:压力485 MPa,保压5 min,乙醇体积分数40%,固液质量体积比(1∶50)g/mL,在此条件下刺五加叶中总黄酮的提取率可达7.76%。超高压提取时间短、提取率高,是由于高压能够显著地提高溶剂渗透的通量和速率,以及在升压和保压阶段,导致细胞内产生剧烈的涡流扩散的结果。超高压提取法是一种全新的快速有效的提取方法。     

Preparation and Characterization of Micronized Artemisinin via a Rapid Expansion of Supercritical Solutions (RESS) Method

The particle sizes of pharmaceutical substances are important for their bioavailability. Bioavailability can be improved by reducing the particle size of the drug. In this study, artemisinin was micronized by the rapid expansion of supercritical solutions (RESS). The particle size of the unprocessed white needle-like artemisinin particles was 30 to 1200 μm. The optimum micronization conditions are determined as follows: extraction temperature of 62 °C, extraction pressure of 25 MPa, precipitation temperature 45 °C and nozzle diameter of 1000 μm. Under the optimum conditions, micronized artemisinin with a (mean particle size) MPS of 550 nm is obtained. By analysis of variance (ANOVA), extraction temperature and pressure have significant effects on the MPS of the micronized artemisinin. The particle size of micronized artemisinin decreased with increasing extraction temperature and pressure. Moreover, the SEM, LC-MS, FTIR, DSC and XRD allowed the comparison between the crystalline initial state and the micronization particles obtained after the RESS process. The results showed that RESS process has not induced degradation of artemisinin and that processed artemisinin particles have lower crystallinity and melting point. The bulk density of artemisinin was determined before and after RESS process and the obtained results showed that it passes from an initial density of 0.554 to 0.128 g·cm(-3) after the processing. The decrease in bulk density of the micronized powder can increase the liquidity of drug particles when they are applied for medicinal preparations. These results suggest micronized powder of artemisinin can be of great potential in drug delivery systems.     

超声提取-膜过滤-超临界萃取联合技术提取青蒿素

将超声提取技术、膜分离技术、超临界流体萃取技术进行了耦合并应用于青蒿素的生产工艺中,讨论了提取试剂、提取方式的差别,考察了膜的选择与运行状况,确定了工艺参数,并进行了乙醇溶液的中试实验,可得收率为0.48%、纯度为92%的青蒿素粗品,为该联合技术的工业化清洁生产提供了借鉴和参考。     

三明产柿叶总黄酮的微波提取研究

采用微波法提取柿叶中总黄酮,探讨了乙醇质量浓度、微波辐射功率、固液比和微波辐射时间等因素对柿叶总黄酮提取率的影响,并用UV和FTIR对提取产物进行了表征.通过单因素实验和正交实验确定最佳提取条件为:乙醇质量浓度65％,固液比1∶ 25(g:mL),微波辐射功率300 W,微波辐射时间15 min(间歇作用5次,每次3 ...     

假奓包叶氨基酸提取纯化工艺及其氨基酸组成分析

用响应面法考察假奓包叶氨基酸提取最佳工艺并确定其氨基酸组成,以氨基酸提取率为评价指标,通过单因素和响应面实验优化其工艺条件并进行氨基酸分析。在盐酸浓度6.1 mol/L,液料比〔即溶液用量(mL)与原料质量(g)的比值,下同〕21.6∶1,水解时间22.3 h,水解温度100℃条件下,氨基酸的提取率为11.21%。再经活性炭脱色、离子交换树脂纯化后得到假奓包叶氨基酸产品。氨基酸分析结果表明,假奓包叶氨基酸产品中总氨基酸质量分数为79.7%,其中必需氨基酸的质量分数达24%,可作为功能性食品或药品的营养添加剂应用。