Studies of iridoid glycosides using liquid chromatography/electrospray ionization tandem mass spectrometry

Fragmentation pathways of five iridoid glycosides have been studied by using electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)). The first-stage MS data of the five iridoid glycosides were compared. The MS spectra showed that the adduct ions of iridoid glycosides and the formate anion were diagnostic ions to distinguish iridoid glycosides with a carboxyl group at the C-4 position or an ester group at the C-4 position. The MS fragmentation pathways of the five iridoid glycosides were also studied. Analyzing the product ion spectra of iridoid glycosides, some neutral losses were observed, such as H(2)O, CO(2) and glucose residues, which were very useful for the identification of the functional groups in the structures of iridoid glycosides. Furthermore, specific loss of one molecule of methyl 3-oxopropanoate or 3-oxopropanic acid was firstly discussed, which corresponded to the isomerization of the hemiacetal group in the structure of iridoid aglycone. According to the fragmentation mechanisms and HPLC/MS(n) data, the structures of five iridoid glycosides in a crude extract of Gardenia jasminoisdes fruit have been identified. Three compounds were compared with standards and the other two were identified as shanzhiside and genipin gentibioside by their MS(n) data without standard compounds. In order to further validate the veracity of the deduction, genipin gentiobioside was isolated from the extract of Gardenia jasminoisdes fruit using Purification Factory and was further identified by C- and H-NMR.     

串联固相萃取法选择性富集白花蛇舌草中的环烯醚萜苷类成分

研究了从白花蛇舌草水提取物中选择性富集环烯醚萜苷类成分的方法。该方法采用硅胶基质的寡聚乙二醇(OEG,实验室自合成)和ODS两种填料依次作为固定相,对白花蛇舌草水提醇沉样品进行固相萃取,并以超高效液相色谱(UPLC)系统对在富集的各个阶段得到的产物进行了色谱表征。实验结果表明,采用该方法得到的终产物的产率为8.21%。从UPLC谱图中可以看出固相萃取环烯醚萜苷类成分选择性富集的过程。终产物中14种典型的环烯醚萜苷类化合物含量明显升高,可达白花蛇舌草水提物的6.1倍,回收率为50.1%,富集效果明显。因此,将白花蛇舌草水提物醇沉后依次经过OEG柱与ODS柱的串联固相萃取可选择性地富集环烯醚萜苷类成分。该方法操作步骤较少,操作简便,选择性好,提取效率较高,富集效果明显。     

Allobetonicoside and 6-O-Acetylmioporoside: Two new iridoid glycosides from Betonica officinalis L.

A new allose-containing iridoid diglycoside, allobetonicoside ( 1 ), and a new acyl iridoid glucoside, 6-O-acetylmioporoside ( 2 ) have been isolated from the aerial parts of Betonica officinalis L. in addition to two known iridoid glucosides, acetylharpagide ( 3 ) and reptoside ( 4 ). Their structures have been determined by spectroscopic methods as well as by means of chemical evidence.     

Two new acylated iridoid glucosides from the aerial parts of Paederia scandens

Two new acylated iridoid glucosides were isolated from the aerial parts of Paederia scandens along with six known iridoid glucosides. The structures of two new compounds were elucidated as 6'-O-E-feruloylmonotropein (1) and 10-O-E-feruloylmonotropein (2) by spectroscopic methods.     

Iridoid-glycoside isolation and purification from Premna fulva leaves

Premna fulva Craib, rich in iridoid glycosides, is widely used to treat periarthritis, osteoproliferation, pain, and other diseases. However, no studies have reported effective purification methods for obtaining iridoid glycosides as active materials. This paper describes an efficient strategy for separating iridoid glycosides from Premna fulva leaves using high-speed counter-current chromatography and preparative high-performance liquid chromatography. A two-phase solvent system, ethyl acetate/n-butanol/water (7.5:2.5:10, v/v), was selected for high-speed counter-current chromatography separation. The proposed method effectively separated and purified four iridoid glycosides and four lignans, including three new iridoid glycosides ( 4–6 ) and five known compounds ( 1–3, 7, 8 ), from Premna fulva leaves, indicating that high-speed counter-current chromatography combined with prep-HPLC can efficiently isolate catalpol derivatives from the genus Premna. Additionally, the in vitro anti-inflammatory activities of all isolated compounds were analyzed using lipopolysaccharide-stimulated RAW 264.7 cells, and the results indicated that six compounds ( 1 and 3–7 ) exhibited potential anti-inflammatory activities.     

山茱萸炮制过程中环烯醚萜苷类成分的质谱研究

利用高效液相色谱-电喷雾多级串联质谱(HPLC-ESI-MSn)联用技术, 对传统中药山茱萸炮制过程中环烯醚萜苷类成分的变化进行了研究. 采用反相C18色谱柱, 二元线性梯度洗脱, 分离并获得了山茱萸中7个环烯醚萜苷类化合物. 并通过电喷雾一级质谱获得了上述7种化合物的分子量信息, 利用电喷雾质谱的源内碰撞诱导解离技术, 获得了该类化合物在负离子模式下的碎裂特征, 在此基础上, 对其进行了结构鉴定和含量分析. 首次发现了差向异构体7α-乙氧基莫诺苷和7β-乙氧基莫诺苷化合物. 研究结果表明, 当采用HPLC-ESI-MS法分析山茱萸环烯醚萜苷类化合物时, 通过色谱保留时间色谱峰面积和质谱特征两方面信息能够提供更加准确可靠的定性定量结果.     

Isolation of two major iridoid glucosides from Incarvillea emodi

Two major iridoid glucosides, namely plantarenaloside, a neurotrophic compound, and boschnaloside, an antibacterial iridoid glucoside, have been isolated from the shoots of Incarvillea emodi (a wild ornamental plant). The compounds are characterised by NMR spectral data and ESI mass spectrometery. This is the first ever report on the isolation of iridoid glucosides from I. emodi (Bignoniaceae).     

An iridoid glucoside dimer and a non-glycosidic iridoid from the leaves of Lasianthus wallichii

A new iridoid glucoside dimer (1) and a non-glycosidic iridoid (2) was isolated together with the known compounds, asperuloside (3), paederoside (4), daphylloside (5), citroside A (6) and benzyl 6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranoside (7), from the leaves of Lasianthus wallichii. The structures of the new compounds were elucidated by spectroscopic and chemical evidence.     

Two new iridoid glycosides from the Tibetan folk medicine Swertia franchetiana

Two new iridoid glycosides designated as senburiside III (2) and senburiside IV (3), together with one known iridoid glycoside senburiside I (1) and three known secoiridoid glucosides swertiamarin (4), gentiopicroside (5) and sweroside (6), were isolated from the whole plant of Swertia franchetiana. The structures of the two new compounds were elucidated by spectroscopic methods.     

Determination of iridoid glycosides in larvae and adults of butterfly<Emphasis Type="Italic"> Melitaea cinxia</Emphasis> by partial filling micellar electrokinetic capillary chromatography—electrospray ionisation mass spectrometry

The iridoid glycosides, methyl catalpol, asperuloside, verbenalin, cinnamoyl catalpol, catalpol and aucubin, were studied from both larvae and adults of butterfly Melitaea cinxia. Special emphasis in the study was put on finding a correlation between the iridoid glycoside content in butterflies and plants. An optimised partial filling micellar electrokinetic capillary chromatographic–electrospray ionisation mass spectrometric (PF-MECC-ESI-MS) method was employed for the separation and identification of the six iridoid glycosides. In this work, the isolation and determination of catalpol and aucubin from extracts of both larvae and adults of Melitaea cinxia butterflies is demonstrated. The PF-MECC-ESI-MS method, using the [M+Na]+, [M+Li]+ and/or [M+NH₄]+ adducts in ESI-MS, was used for quantification of aucubin and catalpol in the insects. In addition, the identification of all analytes was attempted by direct infusion MS/MS analysis. LOQ values for the iridoid glycosides varied between 10 mg/l (for verbenalin) to 50 mg/l (for catalpol and aucubin) corresponding to 0.1% of the sample´s dry mass. A correlation was noticed between the concentrations of iridoid glycosides in plants and the concentrations in larvae feeding on them.     

Rapid quantification of iridoid glycosides analogues in the formulated Chinese medicine Longdan Xiegan Decoction using high-performance liquid chromatography coupled with mass spectrometry [corrected

Longdan Xiegan Decoction (LXD) is a formulated preparation composed of 10 ingredient herbs, with iridoids as the main bioactive components. In this study, a rapid, simple and reliable method of simultaneous determination of four iridoid glycosides in LXD using high-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (MS) was first developed and validated. The four iridoid glycosides references were isolated from LXD extract and purified using a preparative HPLC chromatography. The sample preparation for quantification comprised of a simple ultrasonic extraction and the satisfactory chromatographic separation of the four structurally similar iridoid glycosides was effected in less than three minutes on a CAPCELL PAK C(18) MGII column (3 microm, 100 mm x 2.0 mm), using an elution system of 10% methanol and their concentrations in different batches of LXD and ingredient herbs were simultaneously determined by HPLC-MS/MS using a multiple reaction monitoring (MRM) mode. The method was validated with respect to the overall intra- and inter-day variation (RSD less than 8%) and the limits of quantification for the four iridoid glycosides were 35, 20, 37 and 33 ng/mL, respectively.     

Veronicosid,ein neues Iridoidglucosid aus Veronica officinalisL.(Scrophulariaceae)

Veronicoside, a new iridoid glucoside from Veronica officinalis L. (Scrophulariaceae) A new iridoid glucoside, Veronicoside ( 1 ) has been isolated from Veronica officinalis L. The structure of 1 has been determined by chromatographic and spectroscopic analysis as 6-benzoylcatalpol.     

Determination of iridoid glycosides by micellar electrokinetic capillary chromatography-mass spectrometry with use of the partial filling technique

A fast and easy method was sought for determination of the iridoid glycosides catalpol, ketologanin, verbenalin, loganin, 8-epi-loganic acid, geniposidic acid and 10-cinnamoyl catalpol in plant samples. The method involved micellar electrokinetic capillary chromatography (MEKC) coupled on-line to mass spectrometry. The partial filling technique and electrospray ionization were used. Seven iridoid glycosides could be separated with use of MEKC under basic conditions. However, 8-epi-loganic acid and geniposidic acid could not be detected simultaneously with the five neutral iridoid glycosides by mass spectrometry. Therefore, only the neutral iridoid glycosides were screened from plant samples. Catalpol, verbenalin, loganin and possibly 10-cinnamoyl catalpol were found in an examination of seven plant species in the genera Plantago, Veronica, Melampyrum, Succisa, and Valeriana. Aucubin, which was not included in the sample mixture used in method development because of overlapping with catalpol in MEKC, was also detected. The limits of detection for the iridoid glycosides, both at the UV and at the mass spectrometer, are given.     

New Iridoid Glucosides and a Lignan Diglucoside from Globularia alypumL

The four new iridoid glucosides globularicisin (2) , globularidin (5) , globularimin (9) , and globularinin (13) , the lignan diglucoside liriodendrin (18) , and syringin (20) have been isolated from Globularia alypum L. along with the previously reported glucosides globularin (1) and catalpol (4) . Compound 2 is the first report of any cinnamoyl iridoid with a cis-configuration at the acyl double bond. Compound 5 is another novel iridoid which lacks the characteristic C(3), C(4) double bond in the aglucone part. Compounds 9 and 13 are diastereomeric and contain highly oxygenated aglucone structures. The isolation of liriodendrin, from Globularia alypum is the first demonstration of the occurrence of a lignan in the family Globulariaceae. The structures have been elucidated by ¹ H - and ¹³ C-NMR . spectroscopy as well as by chemical transformations. Taxonomical significance of the cooccurrence of iridoid and lignan glycosides as well as the antileukemic potentiality of the latter are also appraised.     

A New Bis-iridoid Glucoside from Mussaenda incana

Mussaenda incana Wall (Rubiaceae), an endemic medium sized tree of semi-forest regions of North Eastern States of India, is used in traditional medicine as detergent to ulcers and treatment of white leprosy1. Earlier we reported some terpenoids and iridoi…     

Four new iridoid glucosides from Ajuga reptans

Four new iridoid glucosides were isolated from the whole plant of Ajuga reptans L. (Labiatae) along with four known iridoid glucosides, one known diterpenoid glycoside, one known aliphatic alcohol glycoside, and three known ecdysteroids. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence. The diterpenoid glycoside exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and H?O? scavenging activities.     

Iridoid and acyclic monoterpene glycosides, kankanosides L, M, N, O, and P from Cistanche tubulosa

Three iridoid glycosides, kankanosides L, M, and N, and two acyclic monoterpene glycosides, kankanosides O and P, were isolated from fresh stems of Cistanche tubulosa (Orobanchaceae) together with eight iridoid glycosides, five acyclic monoterpene glycosides, three phenylpropanoid glycosides, and four lignan glycosides. Their structures were elucidated on the basis of chemical and physicochemical evidence.     

On the chemical constituents of Dipsacus asper

Bioassay-guided fractionation of 95% EtOH extract from the roots of Dipsacus asper lead to the isolation of some phenolic acids (caffeic acid, 2,6-dihydroxycinnamic acid, vanillic acid, 2'-O-caffeoyl-D-glucopyranoside ester, and caffeoylquinic acid) as the major active components, and five new iridoid glucoside dimers (1-5) and one new iridoid glucoside monomer (6), other known iridoid glycosides loganin, cantleyoside, triplostoside A, lisianthioside, 6'-O-beta-D-apiofuranosyl sweroside, as well as triterpenoids oleanic acid and akebiasaponin D. The structures of new compounds 1-6 were determined as dipsanosides C (1), D (2), E (3), F (4), G (5), and 3'-O-beta-D-glucopyranosyl sweroside (6) by spectroscopic, including 1D and 2D NMR techniques, and chemical methods.     

A new iridoid glycoside from Veronica sibirica

A new iridoid glycoside,versibirioside（1）,and a known iridoid glycoside,verbaspinoside（2）,were isolated from the whole plant of Veronica sibirica L.Their structures were elucidated by spectroscopic methods,including 2D-NMR spectra.     

Monoterpene constituents from Cistanche tubulosa--chemical structures of kankanosides A-E and kankanol-

Four new iridoid glycosides, kankanosides A (1), B (2), C (3), and D (4), a chlorinated iridoid, kankanol (5), and an acyclic monoterpene glycoside, kankanoside E (6), were isolated from the methanolic extract of dried stems of Cistanche tubulosa (SCHRENK) R. WIGHT (Orobanchaceae) together with 16 known compounds. The structures of these new compounds (1-6) were determined on the basis of the chemical and physicochemical evidence.