无患子三萜皂苷研究进展

无患子是一种集工业、药用、观赏、生态于一体的多功能综合利用价值极高的经济树种,近年来,由于其具有较高的商业价值和药理活性,受到了广泛的重视。迄今文献中报道的无患子中分离鉴定的三萜皂苷类化合物有71种,具有抗菌、抗肿瘤、保护心脑血管、保护肝脏、抗生育、杀虫等多种生物活性和良好的非离子表面活性作用,在医药、食品保健、日化和农业等领域应用前景广阔。本文对其皂苷的种类、提取与分离及其应用进行了综述,以期为今后无患子的研究、开发与利用提供参考。     

贴近中学的无患子皂苷制备实验

以苏教版高中化学选修教材《化学与生活》专题一第四单元中“常见洗涤剂”的知识为切入点,介绍天然表面活性剂——无患子皂苷及其工艺制备方法,并在此基础上设计了简易的中学可行的实验操作方案,同时提供了相关的背景知识,融入STS教育理念。     

人参二醇类皂苷的生物转化动态及人参稀有皂苷C-K或F2的制备

为了低成本有效制备人参稀有皂苷C-K或F₂, 将A. niger g.848菌酶用于转化含有人参皂苷(质量分数)分别为49.6% Rb₁, 25.9% Rd, 19.3% Rc和5.23% Rb₂的西洋参二醇混合皂苷. 霉菌发酵时, 采用人参二醇皂苷诱导物比人参提取液诱导物的产酶总活力提高10%~15%. 所产的2种诱导酶均能水解人参二醇皂苷的3-O-和20-O-多种糖基, 均为人参皂苷酶Ⅰ型; 但是人参二醇皂苷诱导物所产酶几乎全部转化人参二醇皂苷为C-K, 而人参提取液诱导物所产酶则残留中间产物. 使用黑曲霉人参二醇皂苷诱导所产酶, 在转化西洋参二醇皂苷的动态研究中发现, 酶反应1.5~2.5 h, 主要为产物F₂; 酶反应12 h后, 主要产物为C-K皂苷. 基于此, 40 g人参二醇类皂苷在45 ℃粗酶反应24 h, 经处理得到含C-K质量分数为87%的23 g酶反应产物, C-K转化率达85%(摩尔分数). 用40 g西洋参二醇皂苷在45 ℃粗酶反应2.5 h, 经处理得到含有质量分数为58%的F₂和27%的C-K的26 g酶反应产物, F₂转化率为50.4%, C-K转化率为29.5%. 通过人参二醇皂苷诱导的黑曲霉粗酶转化人参二醇类皂苷动态研究, 建立了C-K转化率为85%, F₂转化率为50%的制备方法, 为大批量制备提供了基础依据.     

皂苷、皂苷元分子聚集相行为的原子力显微镜研究

用原子力显微镜检测了不同浓度下皂苷和皂苷元的分子聚集相行为.实验表明,当浓度为1.0×10-5 mol/L时,皂苷形成分散较均匀的小片段结构,表现为皂苷分子的聚集体结构;而皂苷元由多个分子连接形成聚集体结构,与皂苷相比高度起伏较低,链的长度较长.浓度为1.0×10-4 mol/L时,皂苷出现了不规则片层与小片段共存结构;皂苷元却形成多孔的网状结构.当浓度增大到1.0×10-3 mol/L时,皂苷小分子紧密聚集、分布在云母表面;皂苷元则形成紧密聚集的大片层多孔结构.结构分析表明,分子官能团的属性对于皂苷和皂苷元分子形成的不同结构起到了关键作用,分子骨架中的糖链阻碍皂苷形成大片层结构,而皂苷元由于分子骨架中羟基间氢键相连接,易于形成大的片层结构.     

田七花提取物中22种皂苷类成分的液相色谱-质谱测定

在甲酸体系中以高效液相色谱负离子模式电喷雾电离质谱以及碰撞诱导裂解技术研究了12种人参皂苷(Re、Rg1、Rg2、Rg3、Rf、Rb1、Rb2、Rb3、Rc、Rd、Rh1 和Rh2).结果表明,应用皂苷化合物(包括人参皂苷、田七皂苷和绞股蓝皂苷)的质谱及裂解规律可在缺少相应对照品的情况下对其进行可靠的鉴定.在此基础上,对田七花样品以加压溶剂萃取法提取,然后以LC-MS/MS分析,从中鉴定出22种皂苷,其中六糖皂苷Ⅰ和Ⅱ、乙酰基Rb1为首次报道,并且定量测定了其中10种皂苷的含量.     

酸枣仁中三萜皂苷的分离和结构研究

从酸枣仁(Zizyphus jujuba Mill. Var. spinosa Hu)中分离得到四个三萜皂苷, 分别鉴定为酸枣仁皂苷G (1, jujuboside G), 酸枣仁皂苷A (2, jujuboside A), 酸枣仁皂苷B (3, jujuboside B)和酸枣仁皂苷A₁ (4, jujuboside A₁). 其中酸枣仁皂苷G与其它酸枣仁皂苷不同, 为新的酮基达玛烷型三萜皂苷. 运用现代波谱技术, 包括二维核磁共振谱和高分辨质谱, 对上述化合物的结构进行了确证.     

HPLC-ELSD测定茜芷胶囊中三七皂苷R1、人参皂苷Rg1及Rb1的含量

利用HPLC-ELSD对茜芷胶囊中的活性成分三七皂苷R1、人参皂苷Rg1和Rb1的含量进行测定.三七皂苷R1、人参皂苷Rg1及Rb1分别在0.13~2.60、0.30~6.00、0.38~7.60μg范围内呈现良好的线性关系,平均回收率分别为98.0%(RSD1.7%),97.1%(RSD1.8%),97.0%(RSD1.5%).该方法简便、准确、重现性好,可用于茜芷胶囊的质量控制.     

川麦冬中的新呋甾皂苷的分离与鉴定

从川麦冬块根总皂苷中分离并鉴定了4个双糖链甾体皂苷化合物, 其中化合物1为新化合物, 化合物2~4是已知化合物.     

人参中人参皂苷的直接高压微波辅助降解

采用高效液相色谱-电喷雾质谱联用法测定了人参提取液中的人参皂苷. 考察了天然人参皂苷发生降解的条件, 同时研究了单体人参皂苷Rg1, Re, Rb1, Rc, Rb2和Rd的降解, 并对降解产物进行了分析. 结果表明, 随着提取压力的升高, 提取液中天然人参皂苷的含量逐渐减少, 同时产生多种次级人参皂苷. 当微波提取压力达到600 kPa, 提取时间为10 min时, 提取液中的主要天然人参皂苷达到完全降解, 次级人参皂苷Rg3含量达到最高. 在单体人参皂苷Rb1, Rc, Rb2和Rd的降解产物中均得到人参皂苷Rg3.     

黄褐毛忍冬中主皂苷成分的结构解析

报道了黄褐毛忍冬中的两个皂苷主成分, 其中化合物1为新化合物, 并对另一个含量最高的皂苷结构进行了修正.     

高效液相色谱-质谱联用分析无患子中的表面活性物质

 应用高效液相色谱和大气压电离质谱联用技术 ,分离分析了无患子果皮中的表面活性成分。根据质谱结果确定其相对分子质量 ,根据源内的碰撞诱导解离 (CID)技术产生的碎片初步推测表面活性物质的结构 ,发现了数个未见文献报道的组分。     

ESI-QqTOF-MS/MS and APCI-IT-MS/MS analysis of steroid saponins from the rhizomes of Dioscorea panthaica

Using high-resolution quadrupole time-of-flight mass spectrometry along with an electrospray ionization source (ESI-QqTOF-MS), accurate molecular weights of 13 steroid saponins extracted from the rhizomes of Dioscorea panthaica were acquired and the corresponding molecular formulae obtained. In order to elucidate the fragmentation pathways of steroid saponins in D. panthaica, 10 authentic samples were investigated using ESI-QqTOF-MS/MS. In addition, atmospheric pressure chemical ionization mass spectrometry combined with ion trap tandem mass spectrometry (APCI-IT-MS/MS) was used to analyze the structures of 13 steroid saponins in D. panthaica. Through the analysis of their tandem mass data, diagnostic fragment ions of the spirostanol and furostanol steroid saponins in D. panthaica were detected as m/z 271.2056 and 253.1951. In addition, four pairs of isomers were detected and the possible structures of four unknown steroid saponins in D. panthaica speculated. ESI-TOF and APCI-MS(n) have proved to be effective tools for research on fragmentation mechanism of steroid saponins and the rapid determination of native steroid saponins in extract mixture, thereby avoiding tedious derivation and separation steps.     

Structural analysis of saponins from medicinal herbs using electrospray ionization tandem mass spectrometry

The underivatized saponins from Tribulus terrestris and Panax ginseng have been investigated by electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)). In ESI-MS spectra, a predominant [M + Na](+) ion in positive mode and [M - H](-) ion in negative mode were observed for molecular mass information. Multi-stage tandem mass spectrometry of the molecular ions was used for detailed structural analysis. Fragment ions from glycoside cleavage can provide information on the mass of aglycone and the primary sequence and branching of oligosaccharide chains in terms of classes of monosaccharides. Fragment ions from cross-ring cleavages of sugar residues can give some information about the linkages between sugar residues. It was found that different alkali metal-cationized adducts with saponins have different degrees of fragmentation, which may originate from the different affinity of a saponin with each alkali metal in the gas phase. ESI-MS(n) has been proven to be an effective tool for rapid determination of native saponins in extract mixtures, thus avoiding tedious derivatization and separation steps.     

Rapid annotation and structural characterization of saponins in the active fraction of Albizia julibrissin by high‐performance liquid chromatography coupled with quadrupole time of flight mass spectrometry based on accurate mass database

The purified active fraction of Albizia julibrissin saponin was proved to be a promising adjuvant candidate for vaccine. In this study, a simple, convenient, and practical strategy was established for characterizing the saponins in this purified active fraction. The personal accurate mass database including chemical structure, molecular formula, and theoretical mass was first constructed by collecting 110 reported known saponins from genus Albizia species. The raw data was obtained by high‐performance liquid chromatography coupled with quadrupole time of flight mass spectrometry. The potential compounds were extracted from raw data, and matched with the accurate mass databases. A series of saponin compounds were predicted and their chemical structures were characterized by interpreting the tandem mass spectrometry data. A total of 29 saponins including 10 new compounds and 5 first found saponins from A. julibrissin were successfully characterized in this purified active fraction using this new strategy.     

Rapid isolation of new furostanol saponins from fenugreek seeds based on ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry

An ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry method was established to rapidly identify and guide the isolation of target saponins from fenugreek seeds. Based on the online screening performance, totally forty-six furostanol saponins were detected and elucidated. Among them, twenty compounds were predicted to be new. To rapidly obtain new furostanol saponins from these seeds, a further phytochemical study was carried out under the guidance of the ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry. Finally, six new furostanol saponins, named as trigoneosides XIV (1), XV (2), XVI (3), XVIIa (4), XVIIb (5), and XIV (6), together with one known furostanol saponin, parvifloside (7), were rapidly obtained, and their definitive structures were determined by NMR and chemical evidence.     

Rapid characterization of triterpene saponins from Conyza blinii by liquid chromatography coupled with mass spectrometry

Conyza blinii Le'vl is a medicinal herb used for the treatment of inflammation in Chinese folk medicine. Its major bioactive constituents are triterpene saponins, most of which contain 6–8 sugar residues. In this report, electrospray ionization tandem mass spectrometry fragmentation behaviors of bisdesmosidic triterpene saponins (conyzasaponin A, B, and C) were studied in both positive and negative ion modes with an ion‐trap mass spectrometer. In full scan mass spectrometry, these saponins gave predominant [M–H]^? and [M+Na]⁺ ions, which determined the molecular weights. In tandem mass spectrometry (MSⁿ, n = 2–4), the [M–H]^? and [M+Na]⁺ ions yielded fragments [Y_0α–H]^? and [B_α+Na]⁺, which were diagnostic for the structures of the triterpene skeleton and sugar chains. The structural elucidation was approved by accurate mass data using IT‐TOF‐MS. An interpretation guideline based on MSⁿ (n = 2–4) diagnostic ions was proposed in order to elucidate the chemical structures of unknown triterpene saponins in C. blinii extract. The saponins in C. blinii were separated by liquid chromatography with a methanol/acetonitrile/water solvent system, and then analyzed by ion‐trap and IT‐TOF mass spectrometers. Based on the interpretation guideline, a total of 35 triterpenoid saponins were tentatively identified. Among them, 15 saponins had been previously reported, and the other 20 saponins were reported from Conyza species for the first time. This study indicates that LC/MS is a powerful technology for the rapid characterization of complicated saponins in herbal extracts. Copyright © 2010 John Wiley & Sons, Ltd.     

穿龙薯蓣化学成分的液相色谱-质谱联用分析

穿龙薯蓣(DiosoreanipponicaMakino)为薯蓣科薯芋属植物,产于内蒙古,黑龙江等省区,其根茎俗称穿山龙,既是生产治疗心血管疾病药物地奥心血康的原料药材,又是用于合成多种甾体激素类药物的原料薯蓣皂苷元的重要来源之一。临床报道穿龙薯蓣总皂苷对治疗冠心病、抗动脉粥样硬化、降血脂、平喘、抗炎和抗肿瘤有一定疗效,其有效部位为穿龙薯蓣甾体皂苷.我们采用高效液相与电喷雾串联质谱联用方法分析穿龙薯蓣中主要的皂苷成分,并发现一种未见报道的甾体皂苷元。     

Rapid identification of saponins in plant extracts by electrospray ionization multi-stage tandem mass spectrometry and liquid chromatography/tandem mass spectrometry

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)) and liquid chromatography coupled with on-line mass spectrometry (LC/MS/MS) were applied to characterize saponins in crude extracts from Panax ginseng. The MS(n) data of the [M - H](-) ions of saponins can provide structural information on the sugar sequences of the saccharide chains and on the sapogins of saponins. By ESI-MS(n), non-isomeric saponins and isomeric saponins with different aglycones can be determined rapidly in plant extracts. LC/MS/MS is a good complementary analytical tool for determination of isomeric saponins. These approaches constitute powerful analytical tools for rapid screening and structural assignment of saponins in plant extracts.     

Rapid structural characterization of triterpenoid saponins in crude extract from Symplocos chinensis using liquid chromatography combined with electrospray ionization tandem mass spectrometry

Triterpenoid saponins in bioactive crude extract from Symplocos chinensis were rapidly identified using electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) and liquid chromatography coupled with sequential mass spectrometry (LC-MSn). According to the characteristic fragmentation behavior of known glucuronide-type triterpenoid saponins isolated from this plant, a total of fourteen constituents in the crude extract were structurally characterized on the basis of their retention time and tandem mass spectrometric analysis, including five pairs of naturally occurring isomers. Except one known saponin formerly obtained, the other constituents were new compounds. The analytical method of LC-MSn combined with ESI-MSn in positive and negative ion modes has been developed for the direct structural elucidation of triterpenoid saponins of this kind in plant extracts.     

Rapid identification of C21 steroidal saponins in Cynanchum versicolor Bunge by electrospray ionization multi-stage tandem mass spectrometry and liquid chromatography/tandem mass spectrometry

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) and liquid chromatography coupled with on-line electrospray ionization tandem mass spectrometry (LC/ESI-MSn) were performed to elucidate the clearage rule of nine investigated C21 steroidal saponins and identify them in the saponin fraction of 90% ethanolic extracts from the root and rhizome of Cynanchum versicolor Bunge. The fragments of C21 steroidal saponins in positive and negative ESI-MSn were used to deduce their mass spectral fragmentation mechanisms, and their structures were further confirmed by ESI-MSn in positive mode. The MSn spectra of the [M+Na]+ ions for saponins provided a wealth of structural information on glycosidic bond cleavage, which allowed a straightforward interpretation of spectra, with respect to the identifications of features such as the sequences of sugars attached to saponins and sugar type. By using LC/ESI-MSn, nine C21 steroidal saponins were detected in the saponin fraction of C. versicolor, and an isomer of atratoglaucoside A was elucidated simultaneously. All nine compounds showed an abundant ion for the loss of 46 Da (HCOOH) from [M+Na]+. The losses of monosaccharide sequences and aglycone as neutral fragmentation from [M+Na-HCOOH]+ were also acquired as the characteristic ions of these C21 steroidal saponins. It provided important information on monosaccharide sequences and in particular on sugar types and could be used to identify and elucidate other C21 steroidal saponins. These studies allowed us to rapidly identify C21 steroidal saponins from Radix cynanchi atrati. It is indicated that the described method had wide applicability to rapidly screen and provide structural confirmation on C21 steroidal saponins in crude materials.