柴胡中柴胡皂甙a的超声辅助溶剂提取

以溶剂提取法为基础,以超声波为辅助手段,对柴胡中的有效成分进行了提取.通过对提取液中柴胡皂甙a量的测定,研究了超声功率、提取温度、提取时间和样品浸渍时间等条件对提取效果的影响,优选出超声辅助溶剂提取的最佳条件为超声功率50%、提取温度50 ℃、提取时间20 min、样品浸渍时间24 h.实验结果表明,超声辅助溶剂提取比普通的溶剂提取具有更高的提取效率.     

超声提取-高效液相色谱法测定农吉利中农吉利甲素

采用甲醇超声提取法提取农吉利中农吉利甲素,用高效液相色谱法(HPLC)测定农吉利甲素的含量.用L9(34)正交试验设计优化了提取溶剂、提取温度、提取时间、料液比等试验条件;以甲醇一三乙胺(0.5+99.5)混合溶液(pH 7.0)为流动相,对生物碱提取液进行了色谱分离,农吉利甲素质量浓度在1.0～800 mg·L-1范围内呈线性关系,方法的检出限(3S/N)为0.1 mg·L-1,加标回收率试验的结果在97.8%～102.3%之间.     

加速溶剂萃取法快速提取黄连中的生物碱

探讨了快速溶剂萃取法（ASE）提取黄连中生物碱的可行性,并比较了该方法与回流提取法和超声提取法的优越性。以黄连中盐酸小檗碱的提取率为指标,以高效液相色谱法（HPLC）为检测方法,用正交实验对快速溶剂萃取法从黄连中提取盐酸小檗碱的工作条件进行优化。最佳仪器参数：提取溶剂为80%乙醇＋0.5%HCl,提取温度为130℃,静态提取时间为10 min,提取次数为1次。快速溶剂萃取法可作为黄连中生物碱分析测定的前处理方法。     

超声波提取含羞草种子中总黄酮工艺条件优化研究

采用超声提取法对含羞草种子中黄酮类物质进行提取,对提取工艺条件如溶剂、配料比、浸泡时间、提取温度、提取时间进行了优化。在单试验的基础上进行正交试验,得出黄酮类物质的最佳提取工艺条件:乙醇体积分数为60%,含羞草种子与60%乙醇配料比(g∶m L)为1∶8,超声温度范围40~44℃,超声时间为50 min。该方法操作简单,提取时间短,提取效率较高。     

微波辐射溶剂提取-分光光度法测定农吉利中的总黄酮

采用微波辐射溶剂法提取农吉利中的总黄酮。研究了微波功率、微波辐射时间、提取溶剂用量、提取温度、提取时间等实验条件。以牡荆素作为目标物表征,利用UV法测定了提取液中总黄酮。实验结果表明:与常规溶剂回流提取相比,在相同的提取条件下用微波辐射处理药材后再进行提取,其提取率明显提高,山东和广西样品中总黄酮的提取率分别提高48.3%和23.2%。该方法的加标回收率为94.2%~105.5%,重复测定结果的相对标准偏差为1.1%(n=6)。该法用于农吉利中总黄酮的提取和测定,处理方法简单,测定结果可靠。     

RP-HPLC法测定烟草中绿原酸含量的研究

采用超声波提取、反相高效液相色谱测定烟叶中绿原酸,用内标法进行定量,并对超声波提取烟叶中绿原酸的提取条件进行了优化,结果表明:用60%的乙醇溶液,在50 ℃、pH 4条件下,超声提取 45 min效果最佳.该法具有良好的线性(相关系数为0.999 9),检测限为 1.4×10-2 mg/10 mL (S/N=3) 加标回收率为 101.5%,方法RSD为1.58%.方法快速、简单、准确.     

气相色谱法测定芝麻中有机氯农药残留量

提出了超声波辅助提取-浓硫酸净化-气相色谱法测定芝麻中多种有机氯农药残留量的方法。在保证足够的准确度、精密度和灵敏度的前提下,对提取溶剂和超声辅助提取的条件进行了优化实验。选择石油醚-丙酮(7∶3,V/V)在40±2℃水浴中超声提取40 min,用浓硫酸净化,各种有机氯农药的回收率在83.4%~109.2%之间,RSD为1.01%~6.21%。该方法消耗溶剂少,能较好用于实际样品分析。     

正交设计优化木贼多糖的超声提取工艺(英文)

以蒸馏水为溶剂提取,通过单因素实验和正交实验,研究料液比、超声功率、超声提取温度和超声作用时间对木贼多糖提取效果的影响。超声提取法的优化工艺条件为:料液比(g/mL)1∶20,提取温度70℃,超声功率100 W,作用时间50 min。在此条件下,木贼多糖的平均提取率为12.33%,RSD为0.16%。超声波强化提取木贼多糖省时高效。     

高效液相色谱-二极管阵列检测器同时测定化妆品中的九种染料及中间体

建立了用高效液相色谱-二极管阵列检测器(HPLC-PDA)同时检测9种染料及中间体的系统方法。首先采用超声提取的方法处理样品,对提取溶剂和提取时间进行了选择,确定用甲醇-0.01 mol/L 乙酸铵(体积比为2∶1)作提取溶剂,超声提取20 min。然后,采用C18柱,以甲醇-0.01 mol/L乙酸铵(pH 6.2)为流动相梯度洗脱,用PDA检测。以保留时间定性,并以紫外吸收光谱图辅助定性,以外标法定量。定量检测波长为230 nm,15 min内可对9种目标物同时进行测定,且各化合物都达到基线分离(分离度大于1.5)。经测定,该方法的平均回收率(n=8)为81.0%～105.6%,相对标准偏差（RSD）为0.8%～4.9%,检出限(以信噪比为3计)为0.1～2 μg。该方法简单、快速,能有效提取和分离测定化妆品中9种染料及中间体。将该方法用于实际化妆品样品的检测,结果令人满意。     

微波辅助微固相萃取-气相色谱/质谱法测定河水中5种有机磷农药

建立了一种微波辅助微固相萃取法,用于提取河水中的5种有机磷农药,用多壁碳纳米管做微固相萃取的吸附剂,对河水中的有机磷农药进行吸附,解析液用气相色谱/质谱法(GC-MS)分析。实验考察了提取温度、时间、解析溶剂的种类、解析时间对目标化合物峰面积的影响。确定最优的实验条件为:微波提取温度为70℃、提取时间为5min、乙酸乙酯为解析溶剂、超声解析的时间为10min。对加标的河水样品进行了分析,所得河水样品中被测物的回收率为94.3%~99.3%,相对标准偏差(RSD)为2.1%~5.9%。     

Structural Features of Fructans from the Root of Cyathula officinalis Kuan

Three fructans (CoPS1, CoPS2 and CoPS3) were isolated from the root of Cyathula officinalis Kuan, a traditional Chinese medicine. The structures of the fructans were determined by methylation, reductive-deavage method combined with GC-MS analysis, and 13C NMR spectroscopy. These results show that the fructans (CoPS1, CoPS2 and CoPS3) are graminan type fructans, and comprised of (2→t)- and (2→6)-linked β-D-fructofuranosyl backbone residues containing high branches.     

Analysis of high-molecular-weight fructan polymers in crude plant extracts by high-resolution LC-MS

The main water-soluble carbohydrates in temperate forage grasses are polymeric fructans. Fructans consist of fructose chains of various chain lengths attached to sucrose as a core molecule. In grasses, fructans are a complex mixture of a large number of isomeric oligomers with a degree of polymerisation ranging from 3 to >100. Accurate monitoring and unambiguous peak identification requires chromatographic separation coupled to mass spectrometry. The mass range of ion trap mass spectrometers is limited, and we show here how monitoring selected multiply charged ions can be used for the detection and quantification of individual isomers and oligomers of high mass, particularly those of high degree of polymerization (DP > 20) in complex plant extracts. Previously reported methods using linear ion traps with low mass resolution have been shown to be useful for the detection of fructans with a DP up to 49. Here, we report a method using high-resolution mass spectrometry (MS) using an Exactive Orbitrap MS which greatly improves the signal-to-noise ratio and allows the detection of fructans up to DP = 100. High-sugar (HS) Lolium perenne cultivars with high concentrations of these fructans have been shown to be of benefit to the pastoral agricultural industry because they improve rumen nitrogen use efficiency and reduce nitrous oxide emissions from pastures. We demonstrate with our method that these HS grasses not only contain increased amounts of fructans in leaf blades but also accumulate fructans with much higher DP compared to cultivars with normal sugar levels.     

A new high-throughput LC-MS method for the analysis of complex fructan mixtures

In this paper, a new liquid chromatography-mass spectrometry (LC-MS) method for the analysis of complex fructan mixtures is presented. In this method, columns with a trifunctional C18 alkyl stationary phase (T3) were used and their performance compared with that of a porous graphitized carbon (PGC) column. The separation of fructan isomers with the T3 phase improved clearly in comparison with the PGC phase, and retention times were lower and more stable. When the T3-based method was applied on a wheat grain extract, multiple fructan isomers could be discerned, even for fructans with a degree of polymerization of 10. This indicates that wheat grain fructans do not, or not only, have a simple linear structure. The presented method paves the way for elucidation of fructan structures in complex mixtures that contain many structural isomers.     

Determination of inulin in foods

A method was developed for determining fructan inulin in various foods (yogurts, honey cakes, chocolates). Warm water was applied for extraction of samples, and mono- and dissacharides were determined by a thin-layer chromatographic densitometric method. A portion of the test solution was hydrolyzed 30 min with 1% oxalic acid in a boiling water bath. Fructose was determined in the hydrolysate. The amount of inulin in a sample was calculated as the difference between the amount of fructose in the sample before and after hydrolysis. The fructose from sucrose formed during the hydrolysis was also considered. The mean recovery from yogurt fortified with 4% inulin was 95.5 +/- 4.5% (mean +/- standard deviation); from honey cakes extract fortified with 10% inulin, 97.3 +/- 5.5%; and from chocolate extract fortified with 30% inulin, 98.6 +/- 6.6% (6 replicates in all cases). Determination of glucose is not necessary for analyzing fructans with the composition expressed shortened to GFn-1 (G, glucose; F, fructosyl) with the average degree of polymerization 8 < or = n < or = 15.     

Antibacterial activity of agave fructans against salmonella typhimurium

Abstract

The objective of this study was to evaluate the antimicrobial effect of Agave fructans against the Salmonella Typhimurium in “in vitro” experiments. The result of the antimicrobial activity was 263.89?±?0, 414.95?±?12.83, 494.54?±?13.88, 522.29?±?0, 580.41?±?14.92?AU for 10, 20, 30, 40 and 50% of Agave fructans (AF) respectively. In addition, there is a significant effect on the growth of the bacteria with all the percentages of AF evaluated (p?<?0.001, R2?=?0.859) with respect to the control. The growth rate of Salmonella with 25% AF was statistically significant compared to the control (?0.7353?±?0.586, 0.0079?±?0.002?D.O./h, respectively; p?>?0.01). Agave fructans could be an alternative to prevent the infections caused by Salmonella.     

Inulin and oligofructose are part of the dietary fiber complex

Dietary fiber has been defined as the remnants of plant cells resistant to hydrolysis by human alimentary enzymes. Its main chemical constituents are hemicelluloses, celluloses, lignin, pectins, gums, and waxes. The U.S. Food and Drug Administration and the U.S. Department of Agriculture determine compliance with nutritional labeling regulations for dietary fiber by use of the existing AOAC INTERNATIONAL methods for total dietary fiber. The above compounds are readily detected by these methods. However, some oligo- and polysaccharides are resistant to human alimentary enzymes and do not precipitate in 78% ethanol, the usual reagent for precipitating dietary fiber in analytical procedures. Some of these saccharides, termed fructans, are inulin and oligofructose. They possess many physiological attributes normally associated with dietary fiber. Inulin is a mixture of oligo- and polysaccharides composed of fructose moieties joined by beta(2-->1) linkages in linear chains. Almost each chain ends with a glucose moiety. Oligofructose is a synonym for fructo-oligosaccharides, with fructose moieties joined by beta(2-->1) linkages, as in inulin. Not all molecules have a glucose unit, and the chain length is less than 10 units. A method for inulin and oligofructose was developed and approved official first action by AOAC INTERNATIONAL in early 1997. It involves extraction of sample and treatment of the extract with amyloglucosidase followed by fructozyme (Fructozyme Enzyme Process Division, Novo Nordisk, Novo Industry, Copenhagen, Denmark). The sugars released in each of the 3 steps are measured by anion-exchange chromatography. The concentration of fructans is calculated as the difference of sugars, glucose and fructose, after the enzymatic treatments and the initial sample. The repeatability standard deviations for inulin and oligofructose ranged from 2.9 to 5.8% and the reproducibility standard deviations ranged from 4.7 to 11.1%. The method was accepted by AOAC INTERNATIONAL.     

Separation and identification of enzymatic sucrose hydrolysis products by high-performance anion-exchange chromatography with pulsed amperometric detection

An accurate carbohydrate analysis method, namely high-performance anion-exchange chromatography with pulsed amperometric detection was successfully applied to the study of sucrose hydrolysis under enzymatic (baker's yeast invertase) conditions. The hydrolysis was monitored by determining sucrose degradation and the corresponding formation of D-glucose, D-fructose and five intermediate fructans using a CarboPac PA-100 (Dionex) analytical anion-exchange column. Highly reproducible results were obtained. The unknown fructans were collected from a semi-preparative CarboPac PA-100 (Dionex) column, neutralized and then desalted on a column containing mixed bed resin AG 501-X8 (D) before identification of the chemical structure. This procedure permitted us to obtain about 20 microg of pure product which is not enough for NMR analysis. Detailed GC-MS analytical data of the methylated compounds indicated that these oligosaccharides were beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (1-kestose), beta-D-Fru-(2 --> 6)-alpha-D-glucopyranoside (6-beta fructofuranosylglucose), beta-D-Fru-(2 --> 1)-beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose) coeluating with a disaccharide.     

Hydrolytic Methods for the Quantification of Fructose Equivalents in Herbaceous Biomass

A low, but significant, fraction of the carbohydrate portion of herbaceous biomass may be composed of fructose/fructosyl-containing components (“fructose equivalents”); such carbohydrates include sucrose, fructooligosaccharides, and fructans. Standard methods used for the quantification of structural-carbohydrate-derived neutral monosaccharide equivalents in biomass are not particularly well suited for the quantification of fructose equivalents due to the inherent instability of fructose in conditions commonly used for hemicellulose/cellulose hydrolysis (>80% degradation of fructose standards treated at 4% sulfuric acid, 121°C, 1 h). Alternative time, temperature, and acid concentration combinations for fructan hydrolysis were considered using model fructans (inulin, β-2,1, and levan, β-2,6) and a grass seed straw (tall fescue, Festuca arundinacea) as representative feedstocks. The instability of fructose, relative to glucose and xylose, at higher acid/temperature combinations is demonstrated, all rates of fructose degradation being acid and temperature dependent. Fructans are shown to be completely hydrolyzed at acid concentrations well below that used for the structural carbohydrates, as low as 0.2%, at 121°C for 1 h. Lower temperatures are also shown to be effective, with corresponding adjustments in acid concentration and time. Thus, fructans can be effectively hydrolyzed under conditions where fructose degradation is maintained below 10%. Hydrolysis of the β-2,1 fructans at temperatures ≥50°C, at all conditions consistent with complete hydrolysis, appears to generate difructose dianhydrides. These same compounds were not detected upon hydrolysis of levan, sucrose, or straw components. It is suggested that fructan hydrolysis conditions be chosen such that hydrolysis goes to completion; fructose degradation is minimized, and difructose dianhydride production is accounted for.     

Agave fructans and oligofructose decrease oxidative stress in brain regions involved in learning and memory of overweight mice

Obesity is currently a public health problem worldwide. Recently, non-reducing carbohydrates, that include β(2→1) and β(2→6) linkages in their structure, have been of particular interest in the field of obesity because they are involved in lipid metabolism. Some of these are agave fructans (AF) and oligofructose (OF). In this study, we evaluated both AF and OF on oxidative stress (OS) markers in the brain of overweight mice (OM). AF and OF decreased TBARS levels and carbonyls at different levels in hippocampus (HP), frontal cortex (FC) and cerebellum (CB) of OM. The results indicated that fructans may have anti-oxidative potential and can be used as an alternative treatment for the prevention of the consequences of this pathology.