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.     

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.     

Analysis of eleven iridoid glycosides by micellar electrokinetic capillary chromatography (MECC) and screening of plant samples by partial filling (MECC)-electrospray ionisation mass spectrometry

Of ammonium, lithium and sodium salts of dodecyl sulfate studied as surfactants in the separation of iridoid glycosides by micellar electrokinetic capillary chromatography (MECC), the last one gave the best results. Eleven neutral iridoid glycosides were separated by MECC with sodium dodecyl sulfate as surfactant, and the water–micelle partition coefficients of the compounds were calculated. The separation system was coupled via a coaxial sheath flow electrospray interface to a mass spectrometer, and the partial filling technique was used in the on-line analysis. Seven plant species belonging to five genera (Plantago, Veronica, Melampyrum, Succisa and Valeriana) were screened for the iridoid glycosides by the new method that was developed. The findings confirmed those of an earlier study on five of the iridoid glycosides. Some new iridoid glycosides were found in Plantago lanceolata, Veronica spicata and V. chamaedrys.     

Characterization and identification of iridoid glucosides,flavonoids and anthraquinones in Hedyotis diffusa by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry

The multiple bioactive constituents in Hedyotis diffusa Willd. (H. diffusa) were extracted and characterized by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC‐ESI‐MSⁿ). The optimized separation condition was obtained using an Agilent ZorBax SB‐C₁₈ column (4.6×150 mm, 5 μm) and gradient elution with water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid), under which baseline separation for the majority of compounds was achieved. Among the compounds detected, 14 iridoid glucosides, 10 flavonoids, 7 anthraquinones, 1 coumarin and 1 triterpene were unambiguously identified or tentatively characterized based on their retention times and mass spectra in comparison with the data from standards or references. The fragmentation behavior for different types of constituents was also investigated, which could contribute to the elucidation of these constituents in H. diffusa. The present study reveals that even more iridoid glycosides were found in H. diffusa than hitherto assumed. The occurrence of two iridoid glucosides and five flavonoids in particular has not yet been described. This paper marks the first report on the structural characterization of chemical compounds in H. diffusa by a developed HPLC‐ESI‐MSⁿ method.     

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 glucosides from the aerial parts of Globularia alypum L. (Globulariaceae)

From the hydromethanolic extract of the aerial parts of Globularia alypum grown in Morocco, a new chlorinated iridoid glucoside, globularioside has been isolated beside 5 known iridoid glycosides, globularin, globularicisin, globularidin, globularinin and globularimin. This is the first report of a chlorinated iridoid in G. alypum and in the Globulareaceae. Unlike all other known 7-chlorinated iridoid glucosides where the chlorine atom exhibits an alpha configuration, globularioside incorporate the chlorine atom as a 7beta substituent. The structures of the isolated compounds were established on the basis of ESI-MS, MS-MS, 1D and 2D NMR spectral analysis.     

Two novel tetrairidoid glucosides from Dipsacus asper

[reaction: see text] Two new iridoid glucoside tetramers, dipsanosides A (1) and B (2), the first-reported iridoid tetramers with four glucosides, were isolated from Dipsacus asper. Their structures were determined by analysis of 1D and 2D NMR data as well as by comparison with model compounds. Their cytotoxicities were tested, but neither of them showed obvious activity.     

Iridoid glucosides from Wendlandia tinctoria roots

Four new iridoid glucosides, 5-dehydro-8-epi-adoxosidic acid, 5-dehydro-8-epi-mussaenoside, 10-O-dihydroferuloyldeacetyldaphylloside, and wendoside, together with one known iridoid glucoside, 8-epi-mussaenoside, beta-D-glucose, D-mannitol and beta-sitosterol have been isolated from the roots of Wendlandia tinctoria. On the basis of chemical and spectral analyses, the structures of new iridoid glucosides have been elucidated.     

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.     

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.     

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.     

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.     

13C NMR spectroscopy of naturally occurring iridoid glucosides and their acylated derivatives

The ¹³C NMR spectra of twenty one iridoid glucosides and fourteen acyl iridoid glucosides of various cyclopentane oxidation states have been analysed and their carbon shifts assigned. Evidence is presented which demonstrates that ¹³C NMR spectroscopy is a valuable and reliable technique for distinguishing the sites of acylation in iridoid glucosides and confirming the predictions of the configuration at C-6 and C-8. A cis configuration of vicinal substituents is generally associated with a substantial increase in shielding, as compared with the trans analog. The ring size and C-1 configuration in the glucose moiety are also evident from the spectra.     

Iridoid and lignan glycosides from Citharexylum spinosum L

From the aerial parts of Citharexylum spinosum L., one new iridoid glucoside, the 7-ss-O-acetate (1) of lamiide, along with four known iridoid glucosides, lamiide (2), lamiidoside (3), duranterectoside C (4), 8-epiloganin (5) and one known lignan glucoside (+)-lyonirenisol-3a-O-ss-D-glucopyranoside (6) were isolated. The compound structures were established by one- and two-dimensional 1H- and 13C-NMR as well as by ESI-MS spectra.     

Iridoids and Cytotoxic Terpenes from Lindenbergia indica

Chemistry of Natural Compounds - A new iridoid aglycone, 1-acetylscyphiphin B2, along with two known iridoid aglycones and three triterpenes, was isolated from the whole plant of Lindenbergia...     

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。     

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 mutagenic new iridoid in the water extract of catalpae fructus

A mutagenic principle in the water extract from Catalpae Fructus (originated from Catalpa ovata G. DON) (Bignoniaceae) was isolated and characterized as a new iridoid named catalpin. The iridoid exhibited mutagenic activity towards Salmonella typhimurium strain TA100 in the presence and absence of rat liver homogenate (S9) mix in Ames' test.     

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.