高效液相色谱-二极管阵列检测/质谱法分析生脉饮煎剂中的人参皂甙类成分

采用高效液相色谱-二极管阵列检测/质谱（HPLC-DAD/MS）联用技术,以10 mmol/L醋酸铵和乙腈混合溶液梯度洗脱 系统为流动相,应用C18色谱柱对生脉饮煎剂中人参皂甙类成分进行分离鉴定。分析结果表明:生脉饮煎剂中主要含有17个 人参皂甙类成分,即20(R)-人参皂甙Rh1、Rh2、Rg3、Rg2,20(S)-人参皂甙Rh1、Rh2、Rg3、Rg2,人参皂甙Rf、Rg6、Rg5 、F4、Rk1、Rk3、Rh4,20(S)-和20(R)-原人参三醇。人参皂甙成分在煎煮过程中发生了很大变化,主要变成了一些中低 极性产物,这是因为煎煮过程中发生了水解、差向异构、脱水等反应。该方法简便、精确、灵敏度高,可以用来分析生脉 饮煎剂中人参皂甙的变化。     

人参皂甙的反相高效液相色谱多台阶梯度优化方法

建立了一种反相高效液相色谱多台阶梯度分离人参皂甙的方法.该方法以乙腈-水溶液为流动相,通过一系列等度实验,获得了8种人参皂甙Rg1,Re,Rf,Rg2,Rb1,Rc,Rb2和Rd的色谱保留参数,发现两参数保留方程不适合用于人参皂甙这种天然产物的分离条件的优化,而三参数保留方程的高精度才可满足预测的要求.在三参数保留方程的基础上,通过计算确定了8种人参皂甙(包括3台阶梯度)的液相色谱分离条件.通过实验对此优化条件进行了验证,实验结果显示了较好的预测精度和分离度.将本方法用于分离人参皂甙,分析时间短且分离度高,显示了等度台阶梯度优化方法对确定色谱分离条件的优越性.     

微生物酶催化制备人参皂苷20(S)-Rg2,20(S)-Rh1和20(S)-PPT

摘要 人参次级皂苷具有较强的抗癌、抗癌转移等药理活性,但由于在人参中含量少或不存在,因此以人参中含量较高的主要人参皂苷制备药效更高的人参次级皂苷不仅有必要,而且很有意义．本文以微生物Microbacterium esteraromaticum GS514的培养液中分离的粗酶为催化剂水解人参皂苷Re和Rg1,并通过1H NMR和13C NMR谱进行了水解产物的结构表征．实验结果表明,反应体系中无机盐NaCl的存在与否直接影响人参皂苷Re,Rg1与粗酶液的反应结果.人参皂苷与粗酶液直接反应,人参皂苷Re不发生反应,人参皂苷Rg1通过C6所连β-D-吡喃葡萄糖的选择性水解转化成人参皂苷F1.如果该反应是在无机盐NaCl存在下进行,人参皂苷Re通过对C20 所连β-D-吡喃葡萄糖的选择性水解定向转化为20(S)-人参皂苷Rg2;人参皂苷Rg1定向转化成20(S)-人参皂苷Rh1以及20(S)-原人参三醇（PPT）.这说明NaCl的加入激活了C20β-D-吡喃葡萄糖苷酶的活性,这对定向合成不同次级人参皂苷具有重要意义.     

大孔树脂分离提取人参茎叶中的人参皂甙

选择了10种大孔吸附树脂,比较其对人参茎叶提取液中人参皂甙的吸附量和解析率,筛选了较优的人参皂甙吸附剂,并对其吸附动力学曲线和动态解析曲线进行了探究。实验结果表明,人参茎叶提取液经LX-R2树脂吸附,用浓度70%的乙醇洗脱,人参皂甙解吸率达92%以上,纯度达85%以上。静态的、动态的吸附、解吸实验表明大孔树脂LX-R2为分离人参皂甙较为理想的吸附材料。     

竹节人参中氨基酸和皂甙特征组分的分析鉴别

建立了利用高效液相色谱法和红外光谱法分析鉴别竹节人参中氨基酸和皂甙的特征组分的方法。分离了竹节人参中的皂甙和水溶性氨基酸, 并对其中的Rb1和Rg1两种人参皂甙以及17种氨基酸进行了定性分析;粗皂甙红外图谱的主要特征峰与Rb1一致。通过与指定的粗皂甙的红外图谱相比较,可鉴定药品的真伪;分析样品色谱图中氨基酸和皂甙等成分的比例,可对该产品进行内在品质的鉴定。该方法简便 快速,所得实验结果代表性强,重现性良好。     

基体辅助激光解吸电解飞行时间质谱用于有参皂甙Rg3的定量分析

考察了基体辅助激光解吸时间飞行质谱用于人参皂甙Rg3定量分析时内标的选择,加入棉子糖作为内标时,Rg3的定量标准曲线的回归系数R^2=0.938,平均相对误差为28.6%,加入性质相近的芦丁后,Rg3的定量标准曲线的回归系数R^2=0.933,平均相对误差为7.5%,分辨率的提高以及采用Rg3和内标物的质谱峰的相对面积来人表Rg3的浓度可以使定量的重现笥明显改善.     

超高效液相色谱-飞行时间质谱快速分析人参根中的皂甙化合物

建立了超高效液相色谱-飞行时间质谱快速分析人参根部提取物中的皂甙类化合物的方法。色谱柱为HSS T3超高效液相色谱柱(100 mm×2.1 mm, 1.8 μm);以15 mmol/L甲酸铵水溶液-乙腈为流动相,采用二元梯度洗脱的方式对人参主根的皂甙提取物进行分离。基于待测目标物的多级质谱碎片离子、精确质量等信息,结合9种人参皂甙标准化合物的多级质谱碎片离子质谱图,共鉴定出人参主根提取物中27种皂甙类化合物。在确定的条件下,以9种人参皂甙标样为研究对象,进行了全面的方法学考察,发现它们的线性范围分别为0.33～9.00 mg/L (Rg1), 0.11～9.00 mg/L (Re), 0.02～2.00 mg/L (Rf), 0.07～6.00 mg/L (Rg2), 0.04～3.00 mg/L (Rb1, Rb3), 0.22～6.00 mg/L (Rc), 0.04～9.00 mg/L (Rb2, Rd);在中等加标浓度时,经内标物峰面积校正的9种皂甙标准化合物的峰面积的相对标准偏差(RSD)不高于11.3%;低、中、高3个质量浓度加标水平的回收率范围分别为90%～100%、98%～104%及96%～103%;最低检出限为3.5～18.5 μg/L。该方法具有高分辨、快捷、简便、可靠等特点,并成功地应用于分析同一产地、不同生长时间的人参干燥主根中皂甙的差异。可以预计此方法可进一步应用于各种人参原料和制品中皂甙的快速测定。     

基体辅助激光解吸电离飞行时间质谱用于人参皂甙Rg3的定量分析

考察了基体辅助激光解吸电离时间飞行质谱用于人参皂甙Rg3 定量分析时内标的选择。加入棉子糖作为内标时 ,Rg3 的定量标准曲线的回归系数R2 =0 .938,平均相对误差为 2 8 6 % ;加入性质相近的芦丁后 ,Rg3 的定量标准曲线的回归系数R2 =0 993,平均相对误差为 7 5 %。分辨率的提高以及采用Rg3 和内标物的质谱峰的相对面积来代表Rg3 的浓度可以使定量的重现性明显改善     

液相色谱-大气压化学电离质谱法分析人参中的人参皂甙

研究了用反相高效液相色谱-大气压化学电离质谱(HPLC/APCI-MS)分析人参皂甙的方法。液相色谱采用乙腈-水流动相进行梯度洗脱,质谱采用正负离子同时扫描并结合二级质谱进行定性,用选择反应离子模式(SRM)测定检测限。实验发现虽然人参皂甙是热不稳定物质,但在大气压化学电离质谱的高温汽化过程中仍能检测到很强的负离子分子离子峰,而且随着汽化温度的升高,人参皂甙的负离子分子离子峰的强度增加。该方法对人参皂甙Rb1和Rg1的检测限分别为1.2×10-13 g和3.0×10-14 g,并检测出白参中包括丙二酰人参皂甙在内的29种人参皂甙。该法灵敏度高,重复性好,结果准确,能有效地对药材提取物中的多种人参皂甙进行检测和结构分析。     

源内裂解液相色谱-质谱鉴别人参皂甙砒和拟人参皂甙F11

研究了利用源内碰撞诱导解离（in-source collision—induced dissociation）的高效液相色谱-大气压化学电离质谱（HPLC—APCI／MS）获取人参和西洋参的化学标志物——人参皂甙Rf和拟人参皂甙F11的特征结构信息及鉴别人参和西洋参的方法。在乙腈-水梯度洗脱反相液相色谱及源内碰撞诱导解离条件下，能获得人参皂甙Rf和拟人参皂甙F11的母核离子及去糖基离子的源内碰撞诱导解离谱，从其差别能清楚区分这对同分异构体。本方法对人参皂甙Rf和拟人参皂甙F11的检出限能达到10^-7g柱上样量，简单、快速，单次质谱实验就能鉴别人参和西洋参。     

Two New Triterpenoids from Saussurea petrovii

Saussurea petrovii Lipsch (Compositae) is a perennial herb mainly distributed in Gansu and Inner Mongolia provinces of China. Its whole herb has been used as a folk remedy for the treatment of rheumatism and bleeding1. In order to find active principles, the chemical constituents of Saussurea petrovii were studied and two new triterpenoids 1 and 2 were isolated from the acetone extract of the rhizome. In this paper, we report the structural elucidation of the compound 1 and 2. Compound 1 wa…     

Regioselective synthesis and structures of anti-cancer 20(R)-ginsenoside Rg3 derivatives

Abstract

Regioselective synthesis of three novel palmitates of 20(R)-ginsenoside Rg₃ was accomplished via a facile strategy, along with complete assignment of their ¹H and ¹³C NMR resonances by 1D and 2D NMR (¹H-¹H COSY, DEPT 135, HSQC, HMBC, and NOESY) techniques. The derivatives were tested for in vitro anti-proliferative activities against pancreatic cancer PANC-1 cells. Compounds 2, 3, and 4 exhibited more potent activity than did 20(R)-ginsenoside Rg₃.     

P123(PEO20-PPO70-PEO20)嵌段共聚物水溶液物理凝胶化行为的耗散粒子动力学模拟

采用耗散粒子动力学(Dissipative particle dynamics, DPD)方法研究了P123(PEO20-PPO70-PEO20)嵌段共聚物水溶液常温下的物理凝胶化行为. 在体积分数(2%~10%)较低时, P123在水溶液中形成球形胶束. 当P123的水溶液体积分数升高到20%时, 会形成柱状胶束. 在P123的水溶液体积分数为30%和40%时, 观察到具有三维网络结构的凝胶. 这些模拟结果不仅与实验结果一致, 而且证明了耗散粒子动力学方法是一种非常适合研究物理凝胶化行为的重要方法. 另外, 在P123的水溶液体积分数为40%时, 研究了凝胶随着时间发展的形成过程.     

Structural determination of two new triterpenoids from Potentilla discolor Bunge by NMR techniques

Two new pentacyclic triterpenoids, 3alpha, 30-dihydroxylup-20(29)-en-27-oic acid (1) and (20S)-3alpha, 29-dihydroxylupan-27-oic acid (2) were isolated from the whole herbs of Potentilla discolor Bunge. The structures of these two new compounds were elucidated, and complete assignments of the (1)H and (13)C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HSQC, HMBC, (1)H-(1)HCOSY and ROESY).     

Microbial carbonylation and hydroxylation of 20(R)-panaxadiol by Aspergillus niger

20(R)-panaxadiol (PD) was metabolised by the fungus Aspergillus niger AS 3.3926 to its C-3 carbonylated metabolite and five other hydroxylated metabolites (1–6). Their structures were elucidated as 3-oxo-20(R)-panaxadiol (1), 3-oxo-7β-hydroxyl- 20(R)-panaxadiol (2), 3-oxo-7β,23α-dihydroxyl-20(R)-panaxadiol (3), 3,12-dioxo- 7β,23β-dihydroxyl-20(R)-panaxadiol (4), 3-oxo-1α,7β-dihydroxyl-20(R)-panaxadiol (5) and 3-oxo-7β,15β-dihydroxyl-20(R)-panaxadiol (6) by spectroscopic analysis. Among them, compounds 2–6 were new compounds. Pharmacological studies revealed that compound 6 exhibited significant anti-hepatic fibrosis activity.     

水热微乳法合成La(OH)3纳米棒的形貌控制研究

自1991年Iijima发现碳纳米管以来,一维纳米材料如纳米管、纳米线、纳米棒和纳米纤维等由于其具有独特的光、电、磁等性质及其潜在的应用前景而引起全世界的广泛关注,一维纳米材料的制备方法有化学气相沉积法、溶胶一凝胶法、催化剂辅助法、固相化学反应法、模板法、溶剂热法、微乳法和水热,微乳法等,其中水热,微乳法是近年来兴起的一种很有发展前途的制备一维纳米材料的方法。     

A novel strategy for rapid quantification of 20(S)-protopanaxatriol and 20(S)-protopanaxadiol saponins in Panax notoginsengP. ginseng and P. quinquefolium

A novel strategy for the qualitative and quantitative determination of 20(S)-protopanaxatriol saponins (PTS) and 20(S)-protopanaxadiol saponins (PDS) in Panax notoginseng, Panax ginseng and Panax quinquefolium, based on the overlapping peaks of main components of PTS (calibrated by ginsenoside Rg1) and PDS (calibrated by ginsenoside Rb1), was proposed. The analysis was performed by using high-performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD). Under specific chromatographic conditions, all samples showed two overlapping peaks containing several main ginsenosides belonging to PTS and PDS, respectively. The overlapping peaks were also identified by using HPLC–MS. Based on the sum and ratio of PTS and PDS, 60 tested Panax samples were divided into three main clusters according to their species. The findings suggested that this strategy provides a simple and rapid approach to quantify PTS and PDS in Panax herbs.     

Selective Oxidation of Betulin by Cr(VI) Reagents

Oxidation of betulin by pyridinium dichromate, pyridinium chlorochromate, and K₂Cr₂O₇ -H₂SO₄ in the presence of tetrabutylammonium bromide was studied. Products of regioselective C-3, C-28-, and exhaustive oxidation, 28-hydroxylup-20(29)-3-one, 3-hydroxy- and 3-oxolup-20(29)-en-28-al were obtained.     

钛酸铋系化合物的光催化性能研究

采用化学溶液分解法制备了钛酸铋化合物: Bi₁₂TiO₂₀, Bi₄Ti₃O₁₂和Bi₂Ti₂O₇, 并采用XRD表征了其结构. 用TEM观察发现其平均粒径＞100 nm, UV-Vis漫反射谱测定显示它们在可见光区均呈现极强的吸收特征. 紫外光照射下甲基橙的光催化降解脱色实验表明, 三种钛酸铋化合物均具有较强的光催化活性, 其中, Bi₁₂TiO₂₀的光催化活性最强, 几乎与P-25相同. 钛酸铋化合物光催化性能的不同在于它们具有不同的晶相结构和电子结构.     

Flammability studies of 3-methyl pyridine/water system

In industrial processes, information on the safety property of chemicals is essentially crucial for safe handling during unit operations. Ensuring the safe use of combustible or flammable substances in processes is unlikely without detailed investigations of their flammability characteristics and related hazards. We studied 3-methyl pyridine (3-picoline), e.g., flammability limits (LFL/UFL), maximum explosion pressure (P _max), maximum explosion pressure rise (dP/dt)_max, minimum oxygen concentration (MOC), vapor deflagration index (K _g), and characterized the influence of inert steam (H₂O) on critical parameters for 3-picoline/water mixtures at 270°C, 1 atm, various oxygen concentrations, and vapor mixing ratios (100/0, 30/70, 10/90 and 5/95 vol.%) with a 20-L-Apparatus in simulated conditions, respectively. The results showed that the flammability characteristics of 3-picoline_(aq) all increased with the oxygen concentration. However, as the composition of inert steam increased, the flammability parameters and the degree of fire and explosion hazards were significantly reduced, instead. This study elucidated the flammability properties of 3-picoline mixed with inert steam. The conclusions could be applied to proactively prevent the relevant processes from incurring fire and explosion accidents.