甜菜碱的电喷雾质谱研究

使用电喷雾质谱检测了糖用甜菜中甜菜碱,并且采用串联质谱技术分析了甜菜碱的碎裂规律。实验结果表明:甜菜碱在酸性条件下检测,在质谱中表现为[M+H]+离子,谱图比较简单,然而在中性条件下检测,簇和及加钠和加钾离子现象严重,谱图比较复杂,因此确定了甜菜碱的检测条件为酸性。在串联质谱中甜菜碱碎裂产生含氮和不含氮的两种特定的子离子,可以作为甜菜碱的定性依据。甜菜提取液不需经过复杂的前处理就可以检测出甜菜碱,操作简单、快速,灵敏度高、特异性好,可以作为复杂体系中甜菜碱的快速检测方法。     

糖用甜菜抗氧化性研究

实验测定了甜菜水提取液和乙醇提取液对DPPH自由基的清除率,并且采用福林-酚比色法测定了这两种提取液中总酚含量。结果表明,乙醇提取液对自由基的清除率(85.3%)高于甜菜中水提取液(59.5%),并且高于文献报道的甜菜渣的乙醇提取液,这与其中的总酚含量呈现正相关性,说明酚酸是甜菜抗氧化成分。实验表明甜菜具有很好的抗氧化性能,这为甜菜的综合开发提供了重要的理论依据。     

电喷雾串联质谱法鉴定甜叶菊干叶中甜菊糖苷的结构

为了对甜叶菊中甜菊糖苷类成分的结构进行鉴定.建立了一种利用电喷雾质谱法鉴定甜叶菊中甜菊糖苷类结构的方法,与液质联用技术不同,该方法不需要复杂的前处理过程,能够直接判断样品中含有的多种甜菊糖苷.结果表明,对甜叶菊中的甜菊糖苷进行电喷雾质谱研究,正离子模式下电离成加氢、钠、钾离子,负离子模式下电离成减氢、加氯离子,并在负离...     

水稻根尖质膜蛋白质组学研究方法的建立

以徐稻3号水稻苗期幼嫩根尖为材料,利用葡聚糖/聚乙二醇两相分配法纯化得到纯度达 90% 的质膜组分,使用优化的双向电泳水化液溶解质膜蛋白,通过等电聚焦/十二烷基磺酸钠 聚丙烯酰胺凝胶双向电泳 （IEF/SDS PAGE）分离和基质辅助激光解吸电离串联飞行时间质谱（MALDI TOF/TOF）分析,鉴定了31个水稻质膜相关蛋白。结果表明IEF/SDS PAGE 双向电泳适合分离亲水性相对较高的膜附着蛋白。进一步利用高盐和温和去污剂对纯化的质膜进行洗涤,以降低质膜组分的复杂程度,通过 SDS PAGE 单向电泳分离和液相色谱串联质谱（LC MS/MS）分析,鉴定了 8个质膜蛋白。经洗涤后的质膜组分复杂度显著降低,SDS PAGE 中的蛋白条带只包含1~2 种蛋白,且主要为疏水性较强的穿膜蛋白,说明多种生物化学分离方法及不同质谱分析的综合运用,是解决生物膜蛋白质组学难点的有效途径。     

复合酶提取人参的高效液相色谱-电喷雾质谱研究

采用高效液相色谱法和电喷雾质谱联用技术并结合紫外光谱技术对复合酶提取的人参化学成分进行了分析,结果表明复合酶可提高人参的提取效率,提取物中人参皂苷Re、Rg1、Rg2、Rb1、Rc、Rb2、Rd、Rk3、Rh4的含量明显增多,并得到了常规提取方法中不能得到的Rk1、Rg5、20(S)-Rg3和20(R)-Rg3。复合酶法提取天然药物并结合高效液相色谱和电喷雾质谱联用技术进行即时分析具有高效,灵敏和直观的特点,以实现对人参中微量成分的检测,并可指导其他天然药物的研究。     

超高效液相色谱-串联质谱同时测定茶叶中高氯酸盐和氯酸盐

建立了超高效液相色谱-串联质谱同时测定茶叶中高氯酸盐和氯酸盐的分析方法。选用ProElut C_(18)固相萃取柱对茶叶提取液进行净化、亲水性的Click Xion色谱柱分离,流动相A为水(含5 mmol·L~(-1)甲酸铵),流动相B为V_(甲醇)︰V_水=9︰1(含5 mmol·L~(-1)甲酸铵),甲酸调节pH至3.2,梯度洗脱分离,UPLC-MS/MS多反应监测(MRM)模式检测。该方法适用于茶叶中高氯酸盐和氯酸盐检测,平均回收率在60.5%~85.8%,RSD在4.9%~7.7%,高氯酸盐检出限为3mg·kg~(-1),氯酸盐检出限为5mg·kg~(-1)。方法操作简单、快速、灵敏度高,可以满足茶叶中高氯酸盐和氯酸盐的检测要求。     

UPLC-MS-MS法测定浓缩菠萝汁中的克百威及3-羟基克百威

建立快速测定动物组织中克百威及其代谢产物3-羟基克百威残留量的液相色谱串联质谱分析方法。浓缩菠萝汁样品中加入无水硫酸钠利用乙腈提取,提取后溶液过Florisil硅土柱和墨炭黑柱,净化后的提取液经氮吹后用0.1%甲酸溶液-乙腈(50:50,V/V)溶解,进行UPLC-MS-MS分析。采用Eclipse Plus C 18色谱柱分离,用0.1%甲酸+5mmol/L乙酸铵水-乙腈作为流动相进行梯度洗脱,电喷雾正离子模式电离,多反应监测模式检测。克百威和三羟基克百威分别在2~50.0μg/L和2~50.0μg/L质量浓度范围内具有良好的线性关系,线性相关系数均大于0.998;在浓缩菠萝汁中克百威和三羟基克百威的方法检测限分别为2μg/kg和2μg/kg。添加范围为2~50μg/kg时,平均回收率在87.2%~99.1%之间,RSD范围在0.367%~2.06%之间。该方法能满足浓缩菠萝汁中克百威及其代谢产物残留量快速分析的要求。     

分子印迹固相萃取和电喷雾质谱法联用测定茶叶中四种儿茶素

为了对茶叶样品中微量儿茶素进行快速准确分析,利用分子印迹固相萃取(MIPs-SPE)与电喷雾质谱(EIMS)联用技术进行了茶叶中四种儿茶素—表儿茶素(EC)、表没食子儿茶素(EGC)、表儿茶素没食子酸酯(ECG)、表没食子儿茶素没食子酸酯(EGCG)的分离测定。首先以表儿茶素(EC)为模板分子,采用紫外聚合方法合成分子印迹聚合物(EC-MIPs),功能单体为甲基丙烯酸(MAA),交联剂为乙烯二醇二甲基丙烯酸酯(EDMA),引发剂为偶氮二异丁腈(AIBN)。利用EC-MIPs作为固定相制备EC-MIPs-SPE柱,对茶叶样品进行分离萃取后采用EIMS对洗脱液中儿茶素单体进行检测,分别与常规C18和非分子印迹聚合物(NIP)固相萃取方法进行比较。结果表明EC-MIPs-SPE法对儿茶素类单体有特异性识别能力,对茶中主要干扰物质咖啡因、茶碱的结合能力远小于儿茶素分子。最佳萃取条件为:水相上样,用50%(v/v)甲醇/水溶液淋洗除去非特异性结合干扰物,1%(v/v)醋酸的甲醇洗脱特异性结合的四种儿茶素单体。对真实茶叶样品测试发现:经过EC-MIPs-SPE法预富集,可以去除94.2%的咖啡因和全部茶碱干扰,同时可得四个主要儿茶素信号,相对强度分别为:EC(12.1%),EGC(8.2%),ECG(35.4%),EGCG(45.7%)。本法可特异性地识别和分离儿茶素单体,有效消除咖啡因和茶碱干扰,可用于茶叶中微量儿茶素分离鉴定。     

超高效液相色谱-串联四级杆质谱联用法测定甘蔗中噻虫胺 的残留

本研究建立了超高效液相色谱串联质谱（UPLC-MS/MS）法检测甘蔗中噻虫胺残留量的方法。甘蔗植株、茎 秆及嫩稍样品经乙腈-水（V∶V=2∶1）提取,Envi-Carb 复合 PSA 固相萃取小柱净化,ACQUITY UPLC BEH C18 色谱 柱分离,电喷雾正离子源（ESI+ ）多反应监测（MRM）模式检测,外标法定量。结果表明：采用 Envi-Carb 固相萃取 小柱,以乙腈为淋洗液,在小柱中添加 PSA 净化效果最好。在甘蔗植株、茎秆及嫩稍中分别添加 0.04、0.4、1 mg/kg 噻虫胺,平均回收率为 81.4%~109.1%,相对标准偏差（RSD）为 0.9%~10.9%。该方法的最小检出量为 0.4 ng,在甘蔗 中的最低检出浓度（LOD）为 0.04 mg/kg,能满足农药残留检测的要求。     

胡椒叶抗氧化物质提取条件初探

采用系统溶剂提取法处理胡椒叶,确定了胡椒叶的乙醇提取相和水提取相具有较强的DPPH自由基清除能力和较高的多酚含量;通过对胡椒嫩叶、完全稳定叶和老叶的乙醇和水提取液的DPPH自由基清除能力和多酚含量的测量,得出胡椒嫩叶的多酚含量较高,抗氧化活性较高,老叶次之;采用不同浓度的乙醇水溶液常温搅拌浸提胡椒老叶,得出50%左右的乙醇水溶液提取液具有较强的清除自由基能力,较高的多酚含量(5.4 g/100g)和黄酮类化合物含量(0.8 g/100g)。     

大豆种子蛋白质组样品制备方法研究

以中黄13大豆成熟种子为材料,采用苯酚甲醇醋酸铵法、三氯乙酸丙酮法和尿素硫脲法进行了蛋白质初提与复提,并利用纳升级液相色谱串联质谱技术(Nano LC-MS/MS)分析比较了尿素硫脲法初提和尿素硫脲法初提后苯酚甲醇醋酸铵法复提的样品,以及一维电泳预分离的尿素硫脲法初提样品,旨在构建能有效提高蛋白质提取率和鉴定率的样品制备方法。结果表明:尿素硫脲法初提结合苯酚甲醇醋酸铵法复提的蛋白得率最高,分别达到29.18%与4.08%;尿素硫脲法初提与尿素硫脲法初提后苯酚甲醇醋酸铵法复提样品中共鉴定到2 246个蛋白质组,初提和复提样品之间差异十分明显;每次独立制备的尿素硫脲法初提样品平均可鉴定到1 167个蛋白质组,经一维电泳预分离后平均可鉴定到1 868个蛋白质组。研究表明,采用适当的蛋白质样品制备和预分离方法,能有效提高大豆种子蛋白质的提取率和鉴定率。     

茶多糖的分级纯化及组成分析

从粗老绿茶中提取茶叶粗多糖,经DEAE-纤维素DE-52和Sephacryl S-300柱层析纯化,获得三个纯化的茶多糖组分：TPS2-H₂O、TPS2-0.25和TPS2-0.40;此三个组分的中性糖含量分别是：41.23％、29.33％和21.39％,糖醛酸含量分别是：19.5%、22.5%和56.4%,蛋白质含量分别是：未检出、0.8％和未检出;GC-MS分析了三个分级组分均由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖等六种单糖构成的杂多糖,其摩尔比分别是TPS2-H2O（21.3:13.8:1.8:23.3:6.9:32.9）,TPS2-0.25（60.7:13.4:1.6:2.0:1.2:21.1）,TPS2-0.40（60.2:10.8:4.4:3.2:5.7:15.7）;HPGPC-ELSD法分析了各组分的分布及所占比重。     

巴西橡胶树胶乳化学成分的GC-MS分析

采用气相色谱-质谱联用(GC-MS)技术,对巴西橡胶树胶乳氯仿、乙酸乙酯萃取物中的化学成分进行分析测定,结合计算机检索技术对其成分进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果表明,氯仿萃取物中共鉴定出33个化学成分,占总量的78.90%。乙酸乙酯萃取物中共鉴定出46个化学成分,占总量的90.15%。其中,τ-杜松醇、(Z)-金合欢醇、角鲨烯、环阿屯醇、24-亚甲基环木菠萝醇等萜类化合物及γ-谷甾醇、β-豆甾醇、菜油甾醇、异岩藻甾醇等植物甾醇在橡胶生物合成途径甲羟戊酸途径中作为中间体或终产物。除24-亚甲基环木菠萝醇以外,几种萜类和甾醇都具有一定药用作用,尤其是角鲨烯,具有抗癌、抗氧化、预防心血管疾病等生理活性,目前已成为天然药物研究的热点。     

Serial batch extraction of zein from milled maize

Prolamine-rich, water insoluble proteins (zeins) can be extracted from milled maize by vigorous mixing in heated ethanol solutions. Whenever solvent extraction is used process cost considerations require that all the solvent be recovered. Because of the low zein content of maize rinsing extract liquid from the extracted maize particles must be done in a way that minimizes dilution. The solid mass fraction of milled grain slurry that can be pumped is 0.25 or less. Because the mass fraction of zein in maize is only approximately 0.05, the zein mass fraction of a batch extract will be less than 0.015. To increase the zein concentration, a batch extract (liquid and fines) can be repeatedly separated from the extracted solid particles and used to extract fresh milled grain. A series of batch extractions with extract reuse can approach the performance of a continuous counter-current solids/liquid extraction, which would be preferable at a commercial scale. Extract reuse is constrained by losses of liquid with the extracted grain and by reductions of the extracting capacity of the extract due to the increasing solute or fines content. By examining the extract composition and yield of a series of batches, it is possible to estimate the zein concentration that could be achieved in a continuous, countercurrent process and to examine effects of higher zein concentrations on extraction that would be inaccessible with a single batch. The centrifugate concentrations for a series of maize extractions in which the extracted maize and extract solution were cooled prior to centrifugation were analyzed. The data were fit with a model based on a maximum zein concentration in the extract. The fit indicates that the protein content of the liquid centrifugate will not exceed 2% for any series of similar batch extractions, by using centrifugation to separate the maize from the extraction slurry after cooling it to ambient temperature. This contrasts with concentrations of zein of 10% or more achieved by extracting corn gluten using similar conditions. Although the concentration of zein in gluten is higher we believe the concentration difference is mainly due to chemical changes to the zein that take place in the gluten production and the methods used to extract zein from gluten.     

Kurilosides A1, A2, C1, D,E and F—Triterpene Glycosides from the Far Eastern Sea Cucumber Thyonidium (= Duasmodactyla) kurilensis (Levin): Structures with Unusual Non-Holostane Aglycones and Cytotoxicities

Six new monosulfated triterpene tetra-, penta- and hexaosides, namely, the kurilosides A₁ (1), A₂ (2), C₁ (3), D (4), E (5) and F (6), as well as the known earlier kuriloside A (7), having unusual non-holostane aglycones without lactone, have been isolated from the sea cucumber Thyonidium (= Duasmodactyla) kurilensis (Levin) (Cucumariidae, Dendrochirotida), collected in the Sea of Okhotsk near Onekotan Island from a depth of 100 m. Structures of the glycosides were established by 2D NMR spectroscopy and HR-ESI mass spectrometry. Kurilosides of the groups A and E contain carbohydrate moieties with a rare architecture (a pentasaccharide branched by C(4) Xyl1), differing from each other in the second monosaccharide residue (quinovose or glucose, correspondingly); kurilosides of the group C are characterized by a unique tetrasaccharide branched by a C(4) Xyl1 sugar chain; and kurilosides of the groups D and F are hexaosides differing from each other in the presence of an O-methyl group in the fourth (terminal) sugar unit. All these glycosides contain a sulfate group at C-6 of the glucose residue attached to C-4 Xyl1 and the non-holostane aglycones have a 9(11) double bond and lack γ-lactone. The cytotoxic activities of compounds 1–7 against mouse neuroblastoma Neuro 2a, normal epithelial JB-6 cells and erythrocytes were studied. Kuriloside A₁ (1) was the most active compound in the series, demonstrating strong cytotoxicity against the erythrocytes and JB-6 cells and a moderate effect against Neuro 2a cells.     

铁观音茶梗中挥发性物质分析

本研究以铁观音茶梗为供试材料,采用顶空进样法-气质联用(HS-GC/MS)技术对其挥发性物质进行提取和检测,利用质谱结合保留指数对其进行定性,并对挥发物种类、相对含量及部分挥发物所具备的生物活性进行比较和探讨。结果表明:从安溪铁观音茶梗中共检测出130种化合物,其中共有的成分108种;采用质谱法(mass spectrometry,MS)完全鉴定出45种、初步鉴定出58种,采用各化合物的保留指数(retention index,RI)鉴定出54种;MS与RI相结合共完全鉴定出68种挥发物。这表明谱库检索与保留指数相结合,有利于提高可定性挥发物的数量以及定性的准确度。在梗中,碳氢类化合物、醛、醇、酯的种类和含量都最为丰富,相对含量高于1%的挥发物有24种,部分挥发物具有麻醉、抑菌、抗癌等生物活性作用,其含量占茶梗挥发物总含量的20.51%。该结果为研究茶梗在形成乌龙茶香气品质中所起的作用及茶梗的综合利用提供理论基础。     

外源添加糖及氨基酸对咖啡果皮酒风味和感官品质的影响

为探究不同外源添加物对咖啡果皮酒风味和感官品质的影响,本研究添加4种可发酵糖（葡萄糖、果糖、麦芽糖和蔗糖）和2种可发酵氨基酸（精氨酸和谷氨酸）发酵生产咖啡果皮酒。以顶空固相微萃取-气相质谱法结合感官评价,分析外源添加物对咖啡果皮酒风味和感官品质的影响。结果表明:共检出9大类75种风味组分,以酯类和醇类为主;添加可发酵糖能显著增加咖啡果皮酒醇类组分（23.99%~121.24%）,添加可发酵氨基酸咖啡果皮酒能增加酯类组分（25.77%~28.18%）,而添加可发酵糖咖啡果皮酒酯类组分显著减少（10.81%~69.94%）;方差齐性检验P=0.206>0.05,在α=0.05的水平上各外源添加物果酒风味组分没有显著性差异,事后两两比较P=(0.371~0.989)>0.05,说明样品间差异不显著,但PCA分析（PC1:96.01%,PC2:3.13%）能将其完全区分;使用模糊数学法感官评判发现,添加精氨酸所酿造的果酒综合得分最高（92.40）,更加适合人们的口味,整体风格显著,协调性好,谷氨酸添加次之（80.80）,果糖和蔗糖所酿造的咖啡果皮酒综合评分一致（78.20）,添加麦芽糖果酒得分最低（74.20）。综上所述,添加氨基酸可改善咖啡果皮酒风味和口感,发酵糖改善效果不如氨基酸。     

Long-Term Feeding of Chitosan Ameliorates Glucose and Lipid Metabolism in a High-Fructose-Diet-Impaired Rat Model of Glucose Tolerance

This study was designed to investigate the effects of long-term feeding of chitosan on plasma glucose and lipids in rats fed a high-fructose (HF) diet (63.1%). Male Sprague-Dawley rats aged seven weeks were used as experimental animals. Rats were divided into three groups: (1) normal group (normal); (2) HF group; (3) chitosan + HF group (HF + C). The rats were fed the experimental diets and drinking water ad libitum for 21 weeks. The results showed that chitosan (average molecular weight was about 3.8 × 10⁵ Dalton and degree of deacetylation was about 89.8%) significantly decreased body weight, paraepididymal fat mass, and retroperitoneal fat mass weight, but elevated the lipolysis rate in retroperitoneal fats of HF diet-fed rats. Supplementation of chitosan causes a decrease in plasma insulin, tumor necrosis factor (TNF)-α, Interleukin (IL)-6, and leptin, and an increase in plasma adiponectin. The HF diet increased hepatic lipids. However, intake of chitosan reduced the accumulation of hepatic lipids, including total cholesterol (TC) and triglyceride (TG) contents. In addition, chitosan elevated the excretion of fecal lipids in HF diet-fed rats. Furthermore, chitosan significantly decreased plasma TC, low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), the TC/high-density lipoprotein cholesterol (HDL-C) ratio, and increased the HDL-C/(LDL-C + VLDL-C) ratio, but elevated the plasma TG and free fatty acids concentrations in HF diet-fed rats. Plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected by the HF diet, but it was significantly increased in chitosan-supplemented, HF-diet-fed rats. The high-fructose diet induced an increase in plasma glucose and impaired glucose tolerance, but chitosan supplementation decreased plasma glucose and improved impairment of glucose tolerance and insulin tolerance. Taken together, these results indicate that supplementation with chitosan can improve the impairment of glucose and lipid metabolism in a HF-diet-fed rat model.     

Relationships involving several types of extractives of five native argentine wood species of genera Prosopis and Acacia

The relationships existing among the values obtained when extracting the wood of four Argentinean species of Prosopis (P. alba, P. kuntzei, P. nigra, and P. ruscifolia) and one of the Acacia (A. aroma) by several procedures were evaluated and discussed. The used methods were: extraction in toluene/ethanol and hot water; determination of tannic and non-tannic content; measurement of phenolic compounds. Additionally, liquid chromatography (HPLC) was also used in order to quantitatively evaluate the content of (−)-mesquitol, a relatively unusual flavonoid (flavanol type). The total amount of Oxidation Products was also measured. They result from oxidation and polymerization processes of phenolic compounds occurring during heartwood formation, and were not separated during chromatographic analysis. Data evidenced a linear trend (R² = 0.970) between organic and tannic extractives of all species, and a similar one (R² = 0.927) between total phenols and tannic (or organic) extractives in the case of heartwood of Prosopis species. Interestingly, for sapwood very different values of organic extracts, tannic content or Oxidation Products type compounds were measured in spite of a similar amount of phenolic substances. Moreover, the various species presented the same peaks in chromatograms, thus evidencing the chemical similarity of compounds but a different quantity between heartwood and sapwood and also among the various species. The observed similarity implied that the various methods of extraction did not really extract only a single class of substances, and that great care must be adopted when using some specific procedures for extractions.Furthermore, the existing relationships between extractives and selected technological properties, namely specific volumetric shrinkage coefficient (BSvol) and natural durability (evaluated in terms of mass loss after fungal attacks in laboratory conditions), were given. It appeared that in heartwood BSvol was well correlated to organic extractives (R² = 0.984), thus evidencing the microimpregnation of cell walls by extractives, but the fitting quality of the correlation was dependent on the type of extractives used. Analogously, a good relationship between mass loss and phenolic compounds existed (R² = 0.764), and in this case the value of R² was even more dependent on the considered extracts. Moreover, the availability of quantitative data on several Prosopis species allowed to consistently evaluate the bioactivity of (−)-mesquitol on the resistance against fungal attack, and the logarithmic form of the relationship between mass loss and (−)-mesquitol content suggested a direct fungicidal activity of this compound. On the other hand, data also evidenced that neither phenolic compounds nor (−)-mesquitol can be considered as the unique and definite factor able to determine the durability of the considered species.     

Anti HSV-1 Activity of Halistanol Sulfate and Halistanol Sulfate C Isolated from Brazilian Marine Sponge Petromica citrina (Demospongiae)

The n-butanol fraction (BF) obtained from the crude extract of the marine sponge Petromica citrina, the halistanol-enriched fraction (TSH fraction), and the isolated compounds halistanol sulfate (1) and halistanol sulfate C (2), were evaluated for their inhibitory effects on the replication of the Herpes Simplex Virus type 1 (HSV-1, KOS strain) by the viral plaque number reduction assay. The TSH fraction was the most effective against HSV-1 replication (SI = 15.33), whereas compounds 1 (SI = 2.46) and 2 (SI = 1.95) were less active. The most active fraction and these compounds were also assayed to determine the viral multiplication step(s) upon which they act as well as their potential synergistic effects. The anti-HSV-1 activity detected was mediated by the inhibition of virus attachment and by the penetration into Vero cells, the virucidal effect on virus particles, and by the impairment in levels of ICP27 and gD proteins of HSV-1. In summary, these results suggest that the anti-HSV-1 activity of TSH fraction detected is possibly related to the synergic effects of compounds 1 and 2.