UPLC-MS/MS结合多探针底物方法研究刺五加叶中黄酮苷类成分对CYP450活性的影响

利用超高效液相色谱-串联质谱联用(UPLC-MS/MS)的多反应监测(MRM)技术结合多探针底物方法, 研究了刺五加叶中的主要黄酮苷类化合物槲皮苷、金丝桃苷及芦丁对肝细胞色素P450酶(CYP450)亚型CYP1A2, CYP2C, CYP2E1, CYP2D和CYP3A活性的影响. 结果表明, 3种化合物对各CYP亚型酶均有抑制作用, 其中金丝桃苷和槲皮苷对CYP1A2催化的非那西丁的O-脱乙基反应抑制的IC₅₀值分别为46.53和49.75 μmol/L, 金丝桃苷和芦丁对CYP2E1催化的氯唑沙宗的6-羟基化反应抑制的IC₅₀值分别为99.87和86.36 μmol/L. 机理性抑制实验结果表明, 3种化合物对2种亚型酶的抑制作用是随着预孵时间延长而增强的机理性抑制.     

降压类中成药及保健食品中21种非法添加化学药物的快速检测与确证方法研究

采用亚3μm色谱柱建立了降压类中成药及保健食品中21种非法添加化学药物的高效液相色谱快速检测及液相色谱-质谱联用确证方法。样品经甲醇-乙腈(体积比5∶5)超声提取,采用Agilent Poroshell 120Phenyl-Hexyl(100 mm×4.6 mm,2.7μm)色谱柱,以甲醇-乙腈(体积比2∶1)-甲酸水溶液(p H 2.5±0.1)为流动相,梯度洗脱,二极管阵列检测器检测,外标法定量,液质联用法进一步定性确证。结果表明,21种成分在17 min内完成分离,方法检出限为0.03~0.50 mg/g,定量下限为0.09~1.50 mg/g,平均回收率为82.0%~109.0%。采用上述方法对107批从互联网收集的样品进行检测,阳性检出率为42.1%。该方法快速、准确,适用于降压类中成药及保健食品中非法添加药物的快速检测。     

采用核磁共振/液相色谱-质谱异相关谱方法开展药用植物草棉活性提取物中多组分的同步结构分析研究

基于不完全分离分析策略,建立了NMR/LC-MS异相关谱(NMR/LC-MS HCS)方法对系列混合物样品的LC-MS和NMR谱数据的整合分析,发掘混合物图谱中来自同一组分的LC-MS和NMR谱数据间的内在相关性.以新疆维吾尔民族药用植物草棉(Gossypium herbaceam L.)花瓣的乙醇提取物(AB-8-2...     

Three New C21 Steroidal Glycosides from the Stems of Marsdenia tenacissima

Three new glycosides, (3β,5α,8α,11α,12β,14β,17α,20R)‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐12‐O‐tigloyl‐8,20 : 11,20‐diepoxypregnane‐12,14‐diol ( 1 ), (3β,5α,8α,11α,12β,14β,17α,20R)‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐ allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐12‐O‐(2‐methylbutanoyl)‐8,20 : 11,20‐diepoxypregnane‐12,14‐diol ( 2 ), and (3β,5α,11α,12β,14β,17α)‐12‐acetoxy‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐20‐oxo‐8,14‐epoxypregnan‐ 11‐yl isobutyrate ( 3 ) were isolated from the stems of Marsdenia tenacissima. The structures of the new compounds were elucidated by means of spectral data, including HR‐ESI‐MS, and 1D‐ and 2D‐NMR.     

Two New C21 Steroidal Glycosides from the Stems of Marsdenia tenacissima

Two new pregnane glycosides, (3β,5α,12β,14β,17α)‐3‐(β‐cymaropyranosyloxy)‐8,14,17,20‐tetrahydroxypregnan‐12‐yl benzoate ( 1 ) and (3β,5α,12β,14β,17α)‐3‐(β‐cymaropyranosyloxy)‐8,14,17,20‐tetrahydroxypregnan‐12‐yl cinnamate ( 2 ) were isolated from the stems of Marsdenia tenacissima. The structures and relative configurations of the new compounds were elucidated by spectroscopic methods, including mass spectrometry and NMR spectroscopy.     

A new C21 steroid glycoside from Marsdenia tenacissima

A new C21 steroid glycoside,11α-O-tigloyl-12-β-O-acetyl tenacigenin B 3-O-β-D-glucopyranosyl-（1→4）-β-D-glucopyr- anosyl-（1→4）-3-O-methyl-6-deoxy-β-D-allopyranosyl-（1→4）-β-D-oleandropyranoside（1）,named tenacissoside N was isolated from the stems of Marsdenia tenacissima.The structure of the glycoside was identified by HR-ESI-MS and NMR spectra.     

Polyoxypregnanes from the stems of Marsdenia tenacissima

From the stems ofMarsdenia tenacissima two new polyoxypregnanes were isolated, their structures were elucidated by 1D, 2D-NMR as 11α,12β-di-O-tigloyl-tenacigenin B （1） and tenacigenoside E （2）.     

Simultaneous quantification of two steroidal glycosides after oral gavage of Marsdenia tenacissima extract in rats using a LC‐MS/MS method

A specific, sensitive and accurate analytical LC‐MS/MS assay was developed for the simultaneous determination of two steroidal glycosides, tenacissoside H and tenacissoside I, in rat plasma. An Agilent ZORBAX SB‐C₁₈ column was used with an isocratic mobile phase system composed of methanol–water–formic acid (70:30:0.1, v/v/v) at a flow rate of 0.3 mL/min. The analysis was performed on a positive ionization electrospray mass spectrometer via selected reaction monitoring mode scan. One‐step protein precipitation with acetonitrile was chosen to extract the analytes from plasma. The lower limits of quantification were 0.9 ng/mL for tenacissoside H and tenacissoside I. The intra‐ and inter‐day precisions were 2.03–11.56 and 3.76–11.62%, respectively, and the accuracies were <110.28% at all quality control levels. The validated method was applied to a pharmacokinetic study in rats after oral gavage of Marsdenia tenacissima extract. Copyright © 2014 John Wiley & Sons, Ltd.     

Three New Pregnane Glycosides from Marsdenia tinctoria

Three new pregnane glycosides, tinctorosides A–C ( 1 – 3 , resp.), together with one known pregnane glycoside, stephanoside B ( 4 ), were isolated from the stems of Marsdenia tinctoria R. Br . (Asclepiadaceae). Their structures were elucidated by extensive spectral methods, especially 2D‐NMR experiments (¹H,¹H‐COSY, HSQC, HMBC, TOCSY, HSQC‐TOCSY, and ROESY), and chemical evidence.     

Dereplication of known pregnane glycosides and structural characterization of novel pregnanes in Marsdenia tenacissima by high‐performance liquid chromatography and electrospray ionization‐tandem mass spectrometry

In the search for novel natural products in plants, particularly those with potential bioactivity, it is important to efficiently distinguish novel compounds from previously isolated, known compounds, a process known as dereplication. In this study, electrospray ionization‐multiple stage tandem mass spectrometry (ESI‐MSⁿ) was used to study the behaviour of 12 pregnane glycosides and genins previously isolated from Marsdenia tenacissima, a traditional Chinese medicinal plant, as a basis for dereplication of compounds in a plant extract. In addition to [M + Na]⁺ and [M + NH₄]⁺ ions, a characteristic [M‐glycosyl + H]⁺ ion was observed in full‐scan mode with in‐source fragmentation. Sequential in‐trap collision‐induced dissociation of [M + Na]⁺ ions from 11,12‐diesters revealed consistent preferred losses of substituents first from C‐12, then from C‐11, followed by losses of monosaccharide fragments from the C‐3 tri‐ and tetrasaccharide substituents. A crude methanol extract of M. tenacissima stems was analysed using high‐performance liquid chromatography coupled to ESI‐MS. Several previously isolated pregnane glycosides were dereplicated, and the presence of an additional nine novel pregnane glycosides is predicted on the basis of the primary and fragment ions observed, including two with a previously unreported C₄H₇O C‐11/C‐12 substituent of pregnane glycosides. This study is the first report of prediction of the structures of novel pregnane glycosides in a crude plant extract by a combination of in‐source fragmentation and in‐trap collision‐induced dissociation and supports the usefulness of LC‐ESI‐MSⁿ not only for dereplication of active compounds in extracts of medicinal plants but also for detecting the presence of novel related compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

Identification of polyoxypregnane glycosides from the stems of Marsdenia tenacissima by high-performance liquid chromatography/tandem mass spectrometry

A facile method based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/(+)ESI-MSⁿ) has been established for the analysis of polyoxypregnane glycosides in the stems of Marsdenia tenacissima. The data reveals the ability of MSⁿ in the structural elucidation of polyoxypregnane glycosides including the nature of the polyoxypregnane core, the kinds of the substituents and the types of sugar residues. Offline Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is also performed to assign accurate elemental compositions. In this study, eighteen polyoxypregnane glycosides have been investigated. Among these components, five compounds are unambiguously identified as Marsdenoside K, Tencissoside A, B, C and D; two compounds are established as novel compounds based on mass spectral data; and the other eleven compound's structures are tentatively proposed. Furthermore, breakdown curves are constructed to distinguish five pairs of isomers among these eighteen compounds. As far as our knowledge, this is the first report on identification of polyoxypregnane glycosides in the stems of M. tenacissima by HPLC/ESI-MSⁿ directly, which could save time and material consuming efforts in traditional phytochemistry analyses.