Structural characterization of iridoid glucosides by ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Potent inhibition of human tyrosinase inhibitor by verproside from the whole plant of Pseudolysimachion rotundum var. subintegrum

Affinity-based ultrafiltration-mass spectrometry coupled with ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry was utilised for the structural identification of direct tyrosinase ligands from a crude Pseudolysimachion rotundum var. subintegrum extract. False positives were recognised by introducing time-dependent inhibition in the control for comparison. The P. rotundum extract contained nine main metabolites in the UPLC-QTOF-MS chromatogram. However, four metabolites were reduced after incubation with tyrosinase, indicating that these metabolites were bound to tyrosinase. The IC50 values of verproside (1) were 31.2 µM and 197.3 µM for mTyr and hTyr, respectively. Verproside showed 5.6-fold higher efficacy than that of its positive control (kojic acid in hTyr). The most potent tyrosinase inhibitor, verproside, features a 3,4-dihydroxybenzoic acid moiety on the iridoid glycoside and inhibits tyrosinase in a time-dependent and competitive manner. Among these three compounds, verproside is bound to the active site pocket with a docking energy of -6.9 kcal/mol and four hydrogen bonding interactions with HIS61 and HIS85.

Identification of pancreatic lipase inhibitors from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Orbitrap MS and in vitro validation

Pancreatic lipase inhibitors can reduce blood lipids by inactivating the catalytic activity of human pancreatic lipase, a key enzyme involved in triglyceride hydrolysis, which helps control some dyslipidemic diseases. The ability of Eucommia ulmoides tea to improve fat-related diseases is closely related to the natural inhibitory components of pancreatic lipase contained in the tea. In this study, fifteen pancreatic lipase inhibitors were screened and identified from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Q-Exactive Orbitrap/MS. Four representative components of geniposidic acid, quercetin-3-O-sambuboside, isochlorogenic acid A, and quercetin with high binding degrees were further verified by nanoscale differential scanning fluorimetry (nanoDSF) and enzyme inhibitory assays. The results of flow cytometry showed that they could significantly reduce the activity of pancreatic lipase in AR42J cells induced by palmitic acid in a concentration-dependent manner. Our findings suggest that Eucommia ulmoides tea may be a promising resource for pancreatic lipase inhibitors of natural origin.

Comprehensive chemical profiling and quantitative analysis of ethnicYi medicine Miao-Fu-Zhi-Tong granules using UHPLC-MS/MS

Developing analytical methods for the chemical components of natural medicines remains a challenge due to its diversity and complexity. Miao-Fu-Zhi-Tong (MFZT) granules, an ethnic Yi herbal prescription, comprises 10 herbs and has been clinically applied for gouty arthritis (GA) therapy. Herein, a series of chemical profiling strategies including in-house library matching, molecular networking and MS/MS fragmentation behavior validation based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) were developed for qualitative analysis of MFZT granules. A total of 207 compounds were identified or characterized in which several rare guanidines were discovered and profiled into alkyl substituted or cyclic subtypes. Moreover, network pharmacology analysis indicated that MFZT's anti-gout mechanism was mostly associated with the nuclear factor kappa-B (NF-κB) signaling, nucleotide oligomerization domain (NOD)-like signaling and rheumatoid arthritis pathways, along with the synergistic effect of 84 potential active compounds. In addition, a quantitative analytical method was developed to simultaneously determine the 29 potential effective components. Among them, berberine, pellodendrine, 3-feruloylquinic acid, neoastilbin, isoacteoside and chlorogenic acid derivatives at higher concentrations were considered as the chemical markers for quality control. These findings provide a holistic chemical basis for MFZT granules and will support the development of effective analytical methods for the herbal formulas of natural medicines.

An integration of UPLC-Q-TOF/MS and chemometrics analysis for the holistic quality evaluation of different geographical Paederia scandens

RATIONALE

Due to the special geographical location and climate of China, there are large differences in the chemical composition and content of Paederia scandens (PS) from different origins, which will have a large impact on its efficacy.

METHODS

An efficient quality control method for PS was established by combining ultra-high-performance liquid chromatography (UPLC) and electrospray ionization mass spectrometry analyses. First, a UPLC-quadrupole time-of-flight mass spectrometry system was employed to identify the chemical composition of PS from seven different origins. Then, the chemical variation in 73 batches of PS samples was subsequently investigated by quantitation of four marker compounds.

RESULTS

A total of 15 common compounds were identified in the samples of PS from seven origins. And four of the marker compounds were chosen based on VIP values to characterize the differences between PS samples of different origins. The linearity ranged between 0.005 and 2.500 mg/mL; the correlation coefficients (r² ) ranged from 0.999 to 1; the limits of detection ranged from 0.013 to 0.033 μg/mL; and the relative standard deviations for repeatability, precisions, and stabilities were below 0.2%, 1.6%, and 0.6%, respectively.

CONCLUSION

The results show that the method can be effective and comprehensive in evaluating the quality of PS from different origins. And this comprehensive strategy proved to be a powerful technique used to differentiate between different geographical herbs.

Structural Characterization and Discrimination of Morinda officinalis and Processing Morinda officinalis Based on Metabolite Profiling Analysis

Morindae officinalis Radix (MOR) is a famous traditional Chinese medicine (TCM) and functional food material for invigorating kidneys and tonifying yang. Processed Morindae officinalis Radix (PMOR) is obtained by steaming MOR. Traditionally, the clinical effects are discrepant between processing and nonprocessing herbal medicines. MOR and PMOR are commonly used in both clinical practice and dietary supplements, and the effect of invigorating kidneys and tonifying yang of PMOR is stronger than MOR. To clarify the overall chemical composition and the difference of MOR and PMOR, a method was developed with an ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). Among the 110 identified components shared by MOR and PMOR, 55 compounds showed significant differences in contents. Among them, the contents of 29 components, including fructooligosaccharides, monotropein, deacetylasperulosidic acid, geniposide, and anthraquinone glycosides, were higher in MOR than in PMOR; the contents of 26 components, including difructose anhydride sucrose, and iridoid glycoside derivatives, were higher in PMOR than in MOR. Difructose anhydrides and iridoid glycoside derivatives were first discovered in PMOR. These results provided a scientific basis for research on the therapeutic material basis of MOR. It would provide a method for the comparison of processing and nonprocessing in Chinese medicines.

Prolonged Administration of Rudgea viburnoides (Cham.) Benth. Prevents Impairment of Redox Status, Renal Dysfunction, and Cardiovascular Damage in 2K1C-Hypertensive Rats by Inhibiting ACE Activity and NO-GMPC Pathway Activation

Rudgea viburnoides is widely found in the Brazilian Cerrado, and commonly used in Brazilian folk medicine. In this study, we evaluated the effects of prolonged administration of the aqueous extract from R. viburnoides leaves (AERV) on impaired redox status, renal dysfunction, and cardiovascular damage in 2K1C hypertensive rats, as well as its chemical composition by LC-DAD-MS. Renal hypertension (two kidney, one-clip model) was surgically induced in male Wistar rats and AERV (30, 100 and 300 mg/kg) was administered orally five weeks after surgery for 28 days. Renal function was assessed and urinary electrolytes, pH, and density were measured. Electrocardiography, blood pressure and heart rate were recorded. Cardiac and mesenteric vascular beds were isolated for cardiac morphometry and evaluation of vascular reactivity, and aortic rings were also isolated for measurement of cyclic guanosine monophosphate levels, and the redox status was assessed. Prolonged treatment with AERV preserved urine excretion and electrolyte levels (Na+, K+, Ca2+ and Cl-), reversed electrocardiographic changes, left ventricular hypertrophy and changes in vascular reactivity induced by hypertension, and reduced blood pressure and heart rate. This effect was associated with a positive modulation of tissue redox state, activation of the NO/cGMP pathway, and inhibition of the angiotensin-converting enzyme. Glycosylated iridoids, chlorogenic acids, glycosylated triterpenes, O-glycosylated flavonols, and triterpenoid saponins were annotated. AERV showed no acute toxicity in female Wistar rats. Therefore, AERV treatment reduced the progression of cardiorenal disease in 2K1C hypertensive rats, which can be involved with an important attenuation of oxidative stress, angiotensin-converting enzyme inhibition, and activation of the NO/cGMP pathway.

Fungal Biotransformation of 2'-Methylflavanone and 2'-Methylflavone as a Method to Obtain Glycosylated Derivatives

Methylated flavonoids are promising pharmaceutical agents due to their improved metabolic stability and increased activity compared to unmethylated forms. The biotransformation in cultures of entomopathogenic filamentous fungi is a valuable method to obtain glycosylated flavones and flavanones with increased aqueous solubility and bioavailability. In the present study, we combined chemical synthesis and biotransformation to obtain methylated and glycosylated flavonoid derivatives. In the first step, we synthesized 2'-methylflavanone and 2'-methylflavone. Afterwards, both compounds were biotransformed in the cultures of two strains of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2. We determined the structures of biotransformation products based on NMR spectroscopy. Biotransformations of 2'-methyflavanone in the culture of B. bassiana KCH J1.5 resulted in three glycosylated flavanones: 2'-methylflavanone 6-O-β-d-(4″-O-methyl)-glucopyranoside, 3'-hydroxy-2'-methylflavanone 6-O-β-d-(4″-O-methyl)-glucopyranoside, and 2-(2'-methylphenyl)-chromane 4-O-β-d-(4″-O-methyl)-glucopyranoside, whereas in the culture of I. fumosorosea KCH J2, two other products were obtained: 2'-methylflavanone 3'-O-β-d-(4″-O-methyl)-glucopyranoside and 2-methylbenzoic acid 4-O-β-d-(4'-O-methyl)-glucopyranoside. 2'-Methylflavone was effectively biotransformed only by I. fumosorosea KCH J2 into three derivatives: 2'-methylflavone 3'-O-β-d-(4″-O-methyl)-glucopyranoside, 2'-methylflavone 4'-O-β-d-(4″-O-methyl)-glucopyranoside, and 2'-methylflavone 5'-O-β-d-(4″-O-methyl)-glucopyranoside. All obtained glycosylated flavonoids have not been described in the literature until now and need further research on their biological activity and pharmacological efficacy as potential drugs.

The integrated study on the chemical profiling and in vivo course to explore the bioactive constituents and potential targets of Chinese classical formula Qingxin Lianzi Yin Decoction by UHPLC-MS and network pharmacology approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Qingxin Lianzi Yin Decoction (QXLZY), a Chinese classical formula, has been widely used in the treatment of various chronic kidney diseases over 1,000 years. However, the current studies on QXLZY were mostly focused on its clinical efficacy, lacking systematic material basis research on constituents.

AIM OF THE STUDY

This work aims to elucidate and quantify the chemical constituents, clarify the blood-absorbed components and excretion pathways, predict major bioactive constituents and discover potential therapeutic targets.

MATERIALS AND METHODS

UHPLC-LTQ-Orbitrap HRMS was employed to clarify the chemical constituents and metabolites of QXLZY. The extraction of diagnostic ion and neutral loss fragment was aimed for searching specific type of constituents. The plasma, urine, bile and feces samples of rats after oral administration of QXLZY were systematically studied. UHPLC-QQQ-MS/MS was employed to simultaneously detect different types of constitutes. Based on the analysis of ingredients in vivo, the bioactive constituents and potential therapeutic targets in the treatment of diabetic nephropathy (DN) was investigated by using network pharmacological analysis.

RESULTS

Totally, 220 compounds were identified or tentatively characterized by UHPLC-LTQ-Orbitrap HRMS. Among them, 59 compounds were confirmed by reference standards. Meanwhile, 21 representative components were simultaneously determined within 15 min by UHPLC-QQQ-MS/MS. 123 components (74 prototypes as well as 49 metabolites) were identified or tentatively characterized. By using network pharmacological analysis, baicalein, liquiritigenin, succinic acid, formononetin, wogonin might be the major effective constituents in QXLZY during the treatment of DN.

CONCLUSIONS

Flavonoids, saponins and organic acids were the major chemical ingredients of QXLZY. Flavonoids were the main components absorbed into blood, followed by organic acids. Phase II conjugation reaction was the major metabolic type. The pathways that QXLZY in the treatment of DN were probably related to glucose and lipid metabolism, oxidative stress and inflammation.

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

Flavonoids are known for their numerous biological activities; however, their pharmacological application is limited by poor bioavailability. Glycosides are usually more stable and more soluble in water and in this form, flavonoids are present in nature. Likewise, the presence of the methyl group in the flavonoid skeleton results in facilitated absorption and greater bioavailability. Entomopathogenic filamentous fungi are effective in the biotransformation of flavonoids; they are known especially for efficient glycosylation. In the current study we used strains of Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2 to biotransform flavonoids with a single methyl group. 2′-Hydroxy-5′-methylchalcone was biotransformed by both strains into 2′-hydroxy-5′-methylchalcone 3-O-β-D-(4″-O-methyl)-glucopyranoside. In the culture of B. bassiana KCH J1.5 four products were obtained from 6-methylflavanone: 4′-hydroxy-6-methylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside; 4′-hydroxyflavanone 6-methylene-O-β-D-(4″-O-methyl)-glucopyranoside; 6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside and 4′-hydroxy-6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside. Biotransformation with I. fumosorosea KCH J2 as a biocatalyst resulted in the formation of 6-methylflavanone 4′-O-β-D-(4″-O-methyl)-glucopyranoside and 2-phenyl-6-methylchromane 4-O-β-D-(4″-O-methyl)-glucopyranoside. All of these flavonoids can be used in biological activity tests and can be useful in studies concerning structure—bioactivity relationships.

The evolutionary origins of the cat attractant nepetalactone in catnip

Catnip or catmint (Nepeta spp.) is a flowering plant in the mint family (Lamiaceae) famed for its ability to attract cats. This phenomenon is caused by the compound nepetalactone, a volatile iridoid that also repels insects. Iridoids are present in many Lamiaceae species but were lost in the ancestor of the Nepetoideae, the subfamily containing Nepeta. Using comparative genomics, ancestral sequence reconstructions, and phylogenetic analyses, we probed the re-emergence of iridoid biosynthesis in Nepeta. The results of these investigations revealed mechanisms for the loss and subsequent re-evolution of iridoid biosynthesis in the Nepeta lineage. We present evidence for a chronology of events that led to the formation of nepetalactone biosynthesis and its metabolic gene cluster. This study provides insights into the interplay between enzyme and genome evolution in the origins, loss, and re-emergence of plant chemical diversity.

Rapid discovery and identification of the anti-inflammatory constituents in Zhi-Shi-Zhi-Zi-Chi-Tang

The anti-inflammatory active ingredients of Zhi-Shi-Zhi-Zi-Chi-Tang (ZSZZCT), a traditional Chinese medicine formula, were predicted and identified using an approach based on activity index, LC-MS, semi-preparative LC and NMR. Firstly, the whole extract of ZSZZCT was analyzed using liquid chromatography-quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) and liquid chromatography - ion trap mass spectrometry (LC-IT-MS), 79 constituents were detected and 39 constituents were identified unambiguously or tentatively. Subsequently, the whole extract of the formula was separated into multiple components and the activity index method was used to calculate index values of the 79 constituents by integrating the chemical and pharmacological information of multiple components. Four polymethoxyl flavones were predicted as the major active constituents according to the activity index values. Furthermore, three polymethoxyl flavones were prepared using the strategy with semi-preparative LC guided by LC-MS, and their anti-inflammatory activities were validated. The results show that three polymethoxyl flavones with higher positive index values, i.e., 3, 5, 6, 7, 8, 3', 4'-heptamethoxyflavone, 3-hydroxynobiletein and tangeretin had significant anti-inflammatory effects. In conclusion, the predicted results indicated that the activity index method is feasible for the accurate prediction of active constituents in TCM formulae.

Simultaneous Analysis of Iridoid Glycosides and Anthraquinones in Morinda officinalis Using UPLC-QqQ-MS/MS and UPLC-Q/TOF-MSE

Morinda officinalis is an important herbal medicine and functional food, and its main constituents include anthraquinone and iridoid glycosides. Quantification of the main compounds is a necessary step to understand the quality and therapeutic properties of M. officinalis, but this has not yet been performed based on liquid chromatography/tandem mass spectrometry (LC-MS/MS). Analytes were extracted from M. officinalis by reflux method. Ultrahigh-performance liquid chromatography coupled with a triple quadrupole mass spectrometry (UPLC-QqQ-MS) using multiple reaction monitoring (MRM) mode was applied for quantification. Fragmentation pathways of deacetyl asperulosidic acid and rubiadin were investigated based on UPLC with quadrupole time-of-flight tandem mass spectrometry (Q/TOF-MS) in the MS^E centroid mode. The method showed a good linearity over a wide concentration range (R² ≥ 0.9930). The limits of quantification of six compounds ranged from 2.6 to 27.57 ng/mL. The intra- and inter-day precisions of the investigated components exhibited an RSD within 4.5% with mean recovery rates of 95.32–99.86%. Contents of selected compounds in M. officinalis varied significantly depending on region. The fragmentation pathway of deacetyl asperulosidic and rubiadin was proposed. A selective and sensitive method was developed for determining six target compounds in M. officinalis by UPLC-MS/MS. Furthermore, the proposed method will be helpful for quality control and identification main compounds of M. officinalis.

Ash leaf metabolomes reveal differences between trees tolerant and susceptible to ash dieback disease

European common ash, Fraxinus excelsior, is currently threatened by Ash dieback (ADB) caused by the fungus, Hymenoscyphus fraxineus. To detect and identify metabolites that may be products of pathways important in contributing to resistance against H. fraxineus, we performed untargeted metabolomic profiling on leaves from five high-susceptibility and five low-susceptibility F. excelsior individuals identified during Danish field trials. We describe in this study, two datasets. The first is untargeted LC-MS metabolomics raw data from ash leaves with high-susceptibility and low-susceptibility to ADB in positive and negative mode. These data allow the application of peak picking, alignment, gap-filling and retention-time correlation analyses to be performed in alternative ways. The second, a processed dataset containing abundances of aligned features across all samples enables further mining of the data. Here we illustrate the utility of this dataset which has previously been used to identify putative iridoid glycosides, well known anti-herbivory terpenoid derivatives, and show differential abundance in tolerant and susceptible ash samples.

Genome sequence and genetic diversity of European ash trees

Ash trees (genus Fraxinus, family Oleaceae) are widespread throughout the Northern Hemisphere, but are being devastated in Europe by the fungus Hymenoscyphus fraxineus, causing ash dieback, and in North America by the herbivorous beetle Agrilus planipennis. Here we sequence the genome of a low-heterozygosity Fraxinus excelsior tree from Gloucestershire, UK, annotating 38,852 protein-coding genes of which 25% appear ash specific when compared with the genomes of ten other plant species. Analyses of paralogous genes suggest a whole-genome duplication shared with olive (Olea europaea, Oleaceae). We also re-sequence 37 F. excelsior trees from Europe, finding evidence for apparent long-term decline in effective population size. Using our reference sequence, we re-analyse association transcriptomic data, yielding improved markers for reduced susceptibility to ash dieback. Surveys of these markers in British populations suggest that reduced susceptibility to ash dieback may be more widespread in Great Britain than in Denmark. We also present evidence that susceptibility of trees to H. fraxineus is associated with their iridoid glycoside levels. This rapid, integrated, multidisciplinary research response to an emerging health threat in a non-model organism opens the way for mitigation of the epidemic.

LC-PDA-ESI-MSn analysis of phenolic and iridoid compounds from Globularia spp

Plants produce a great number of metabolites with potentially useful biological activities. Species from the genus Globularia (Plantaginaceae) are known as sources of different phenolic and iridoid compounds. Globularia alypum L. is a medicinal plant used as a healing agent in many Mediterranean countries. Similarities in phytochemical composition are often observed for related species. For Globularia spp., such findings were mostly based on identification of several isolated compounds from distinct species. To our knowledge, this is the first study that enables simultaneous comparison of phytochemical profiles from several members of the genus Globularia. Liquid chromatography-photodiode array detection-electrospray ionization-tandem mass spectrometry was used for the analysis of methanolic extracts of aerial parts obtained from four Globularia species (G. alypum, G. punctata, G. cordifolia and G. meridionalis). In total, 85 compounds were identified or tentatively identified based on comparison of their retention time, UV and MSⁿ (up to MS⁴ ) spectra to those of standard compounds and/or to literature data. Among these, high relative amounts of bioactive molecules such as globularin, globularifolin, asperuloside and verbascoside (acteoside) were found. Apart from providing new insights into the phytochemistry and chemotaxonomy of selected Globularia species, results of this study complement existing MS/MS spectral data and could enable easier mass spectrometric profiling of certain bioactive compounds such as iridoids and phenylethanoids in related plant species, genera and families. Copyright © 2016 John Wiley & Sons, Ltd.

Target and non-target identification of chemical components in Lamiophlomis rotata by liquid chromatography/quadrupole time-of-flight mass spectrometry using a three-step protocol

RATIONALE

As a herbal plant used in traditional Chinese medicine, Lamiophlomis rotata (Benth.) Kudo mainly displays its pharmacological effect by promoting blood circulation and hemostasis, dispelling wind, and acting as an analgesic. To identify the components contained in L. rotata, global detection and structural elucidation of both target and non-target components in the medicinal material was performed.

METHODS

L. rotata was ultrasonically extracted with methanol. Separation and analysis were achieved using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS). A three-step protocol which included (1) potential components screening, (2) collection of qualitative information, and (3) database searching and structural elucidation was used for target and non-target identification.

RESULTS

A total of 42 components were tentatively identified, which included 12 iridoids (2 aglycones and 10 glucosides), 11 flavonoids (4 aglycones and 7 glucosides), and 13 phenylethanoid glycosides. Moreover, components of L. rotata extract belonging to the three main structural categories could be well separated in a 3D point plot according to their retention times, mass defects and degrees of unsaturation, facilitating the structural classification and identification in the subsequent studies.

CONCLUSIONS

The results provide a reasonable picture of the components contained in L. rotata extract and promote the further pharmacodynamic and/or pharmacokinetic characterization of this medical material, meanwhile demonstrating the utility of a universal methodology for the systematical study of herbal medicines. Copyright © 2016 John Wiley & Sons, Ltd.

Iridoid glycoside permethylation enhances chromatographic separation and chemical ionization

RATIONALE

While natural products isolated from medicinal plants can serve as a rich source of biologically active metabolites, mixtures of structurally related compounds of a polar nature are often difficult to chemically resolve by traditional separation techniques. Chemical derivatization to reduce metabolite polarity combined with liquid chromatography (LC) is the strategy presented here to resolve a mixture of structurally related natural product glycosides solvent extracted from the medicinal herb Teucrium polium for mass spectrometric characterization.

METHODS

The partially purified plant extract was subjected to chemical derivatization and electrospray ionization mass spectrometry (ESI-MS) fragmentation pattern analysis allowed for structural characterization of iridoid and secoiridoid glycosides. Selected ions were subjected to tandem mass spectrometric (MS/MS) analysis with a relatively higher-energy collision dissociation to assist in structural elucidation.

RESULTS

Permethylation replaced all protons from free hydroxyl and amino groups with methyls and resulted in increases in both hydrophobicity, for facilitated chromatographic separation, and proton affinity, for enhanced chemical ionization. Protonated and/or sodiated adducts were observed for the six compounds detected in positive-ion mode ESI-MS with a mass accuracy of less than 2 ppm.

CONCLUSIONS

Permethylation combined with LC/MS analysis is shown here to be an effective chemical practice for separating and characterizing iridoid glucosinolates and is expected to be well suited for the chemical characterization of other polar natural-product mixtures of closely related compounds. Copyright © 2016 John Wiley & Sons, Ltd.

Identification of Iridoids in Edible Honeysuckle Berries (Lonicera caerulea L. var. kamtschatica Sevast.) by UPLC-ESI-qTOF-MS/MS

Iridoid profiles of honeysuckle berry were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry UPLC-ESI-qTOF-MS/MS in positive and negative ions mode. The MS fragmentation pathways of detected iridoid glycosides were also studied in both modes. In the negative ESI mass spectra, iridoids with a methyl ester or lactone structure have preferentially produced adduct [M + HCOOH - H](-) ions. However, protonated ions of molecular fragments, which were released by glycosidic bond cleavage and following fragmentation of aglycone rings, were more usable for iridoid structure analysis. In addition, the neutral losses of H₂O, CO, CO₂, CH₃OH, acetylene, ethenone and cyclopropynone have provided data confirming the presence of functional substituents in the aglycone. Among the 13 iridoids, 11 were identified in honeysuckle berries for the first time: pentosides of loganic acid (two isomers), pentosides of loganin (three isomers), pentosyl sweroside, and additionally 7-epi-loganic acid, 7-epi-loganin, sweroside, secologanin, and secoxyloganin. The five pentoside derivatives of loganic acid and loganin have not been previously detected in the analyzed species. Honeysuckle berries are a source of iridoids with different structures, compounds that are rarely present in fruits.

Study on anti-inflammatory efficacy and correlative ingredients with pharmacodynamics detected in acute inflammation rat model serum from Caulis Lonicerae japonicae

BACKGROUND

Caulis Lonicerae japonicae (CLJ) is often used for the treatment of inflammation such as acute fever, headache, respiratory infection and epidemic diseases. Nevertheless, domestic and foreign researches simply fail to focus on reports of CLJ, especially its anti-inflammatory effects and correlative components.

PURPOSE

In this study, we investigated anti-inflammatory effects and serum components of Caulis Lonicerae japonicae (CLJ) in models of acute inflammation and correlative analysis between anti-inflammatory effects and serum components of CLJ in rat serum to analyze the changes in the relative contents of components in serum with time and in the corresponding values to characterize active fractions of CLJ and identify the major active components of CLJ in rats.

STUDY DESIGN

Active fractions of CLJ were screened using xylene-induced ear oedema mice model. Anti-inflammatory effects were evaluated using carrageenan-induced paw oedema rat model, and then correlative components in rat serum were demonstrated with HPLC-QTOF/MS/MS method explored.

METHODS

HPLC-QTOF/MS/MS was developed to analyze the components absorbed in rat serum after oral administration of CLJ.

RESULTS

Ethyl acetate extracts (ECLJ) and n-butanol extracts (BCLJ) of CLJ were preliminarily screened as active fractions of CLJ (EBCLJ) using xylene-induced ear oedema mice model, and effectively inhibited edema and values of interleukin-1 (IL-l), nuclear factor-kappaB (NF-kB), tumor necrosis factor-α (TNF-α) activities and prostaglandinE2 (PGE2) productions using carrageenan-induced paw oedema rat model. 33 peaks were found in total ion current chromatograms of EBCLJ, and 27 components were observed in EBCLJ-treated rat serum, only 11 of which were correlated with anti-inflammatory effects.

CONCLUSIONS

The present study contributes to the study on the pharmacodynamic basis of CLJ and provides potent evidence for developing CLJ as a safe and promising natural drug in inflammation treatment.

Rapid Identification and Assignation of the Active Ingredients in Fufang Banbianlian Injection Using HPLC-DAD-ESI-IT-TOF-MS

Fufang Banbianlian Injection (FBI) is a well-known traditional Chinese medicine formula composed of three herbal medicines. However, the systematic investigation on its chemical components has not been reported yet. In this study, a high-performance liquid chromatography combined with diode-array detector, and coupled to an electrospray ionization with ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method, was established for the identification of chemical profile in FBI. Sixty-six major constituents (14 phenolic acids, 14 iridoids, 20 flavonoids, 2 benzylideneacetone compounds, 3 phenylethanoid glycosides, 1 coumarin, 1 lignan, 3 nucleosides, 1 amino acids, 1 monosaccharides, 2 oligosaccharides, 3 alduronic acids and citric acid) were identified or tentatively characterized by comparing their retention times and MS spectra with those of standards or literature data. Finally, all constituents were further assigned in the individual herbs (InHs), although some of them were from multiple InHs. As a result, 11 compounds were from Lobelia chinensis Lour, 33 compounds were from Scutellaria barbata D. Don and 38 compounds were from Hedyotis diffusa Willd. In conclusion, the developed HPLC-DAD-ESI-IT-TOF-MS method is a rapid and efficient technique for analysis of FBI sample, and could be a valuable method for the further study on the quality control of the FBI.

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-MS(n)). 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-MS(n) method.

Comprehensive identification of 125 multifarious constituents in Shuang-huang-lian powder injection by HPLC-DAD-ESI-IT-TOF-MS

A high-performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method was established for excellent separation and structural identification of constituents in Shuang-huang-lian powder injection (SHLPI). The typical ultraviolet absorptions, accurate empirical molecular formula and reasonable fragmentation mechanisms of these ingredients were used for their structural elucidation. In consequence, 125 constituents (33 phenolic acids, 29 flavonoids, 32 phenylethanoid glycosides, 15 iridoid glycosides, 8 lignans, 3 amino acids and 2 purines nucleosides, 2 quinoid glycosides and 1 alkylbenzene glycoside) were either unequivocally identified or tentatively characterized by comparing authentic standards or published data. The result showed that this study could provide valuable information for the quality control and further investigation of SHLPI formula.

Rapid identification of erythrocyte phospholipids in Sprague-Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague-Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry with MassLynx(TM) MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time-of-flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub-2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in-house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague-Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.

Teucrium polium phenylethanol and iridoid glycoside characterization and flavonoid inhibition of biofilm-forming Staphylococcus aureus

The chemical composition and biofilm regulation of 15 metabolites from Teucrium polium are reported. Compounds were isolated from a CH2Cl2-MeOH extract of the aerial parts of the plant and included iridoid and phenylethanol glycosides and a monoterpenoid, together with nine known compounds. The structures were elucidated based on standard spectroscopic (UV, (1)H and (13)C NMR), 2D NMR ((1)H-(1)H COSY, HMQC, HMBC, and NOESY), and/or LC-ESIMS/MS data analyses. Inhibition of the biofilm-forming strain Staphylococcus aureus was observed with exposure to compounds 7 and 8.

Influence of the stage of ripeness on the composition of iridoids and phenolic compounds in genipap (Genipa americana L.)

Genipap fruits, native to the Amazon region, were classified in relation to their stage of ripeness according to firmness and peel color. The influence of the part of the genipap fruit and ripeness stage on the iridoid and phenolic compound profiles was evaluated by HPLC-DAD-MS(n), and a total of 17 compounds were identified. Geniposide was the major compound in both parts of the unripe genipap fruits, representing >70% of the total iridoids, whereas 5-caffeoylquinic acid was the major phenolic compound. In ripe fruits, genipin gentiobioside was the major compound in the endocarp (38%) and no phenolic compounds were detected. During ripening, the total iridoid content decreased by >90%, which could explain the absence of blue pigment formation in the ripe fruits after their injury. This is the first time that the phenolic compound composition and iridoid contents of genipap fruits have been reported in the literature.

Constituent analysis and quality control of Lamiophlomis rotata by LC-TOF/MS and HPLC-UV

In the present study, chemical profile analysis for Lamiophlomis rotata, a classic Tibetan folk medicine, was illustrated by an ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (LC-TOF/MS) method, which provided evidence for the certain identification of the main constituents, including iridoids, flavonoids and phenylethanoid glycosides. Among these compounds, nine of them were regarded as marker compounds for the quantitative evaluation of L. rotata, using a simple and reliable method by HPLC with ultraviolet, in combination of chromatographic fingerprint analysis. Separation was achieved on a Waters SunFire C18 analytical column with linear gradient elution of acetonitrile and 0.1% formic acid aqueous solution. The validated method was successfully applied to evaluate twelve batches of L. rotata. Assay results showed that nine compounds did not vary significantly from the aerial parts and the whole plant for each batch, and was consistent with the fingerprint analysis, which confirmed the medicine parts alteration in Chinese Pharmacopoeia from the perspective of chemical components.

Effective 2D-RPLC/RPLC enrichment and separation of micro-components from Hedyotis diffusa Willd. and characterization by using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

An effective method aiming at enrichment and analysis of micro-components in traditional Chinese medicine (TCM) was developed. One fraction (fraction E) from the extract of Hedyotis diffusa Willd. was selected as test sample, which was isolated by using the XAD-4 macroporous resin. To study the micro-components, a two-dimensional reverse-phase liquid chromatography (2D-RPLC/RPLC) method was developed, comprising Click OEG and C18 stationary phases as the first and second dimensions, respectively. Of the eight sub-fractions isolated from the first dimension, three sub-fractions (fractions II-IV) containing micro-components were further separated with the second dimension. The 2D-RPLC/RPLC system was proved to possess high orthogonality. Furthermore, the micro-components were characterized by using ultra-performance liquid chromatography-diode array detector/quadrupole time-of-flight mass spectrometry (UPLC-DAD/Q-TOF MS) with electrospray ionization (ESI) source. With the optimized separation and characterization method, a large number (>400) of micro-components were enriched and detected from the extracts of H. diffusa Willd., the majority of which has not been isolated from the herb before. Among these isolated micro-components, 38 compounds involving 24 phenylpropanoids, 7 flavonoids and 7 iridoid glucosides (IGs), were identified or tentatively identified from the H. diffusa extracts on the basis of spectral data of the authentic standards and the fragmentation characteristics information available in literatures. The proposed method made it possible to effectively screen and analyze the micro-components in TCMs or other complex natural medicines.

HPLC/qTOF-MS-oriented characteristic components data set and chemometric analysis for the holistic quality control of complex TCM preparations: Niuhuang Shangqing pill as an example

The quality control of Da-Fu-Fang (DFF), referring to the traditional Chinese medicine (TCM) preparations comprising more than 10 TCMs, is challenging due to their extreme chemical complexity. In this study, a strategy is proposed for the holistic quality control of DFFs based on HPLC/qTOF-MS-oriented characteristic components data set (CCDS) and chemometric analysis. Niuhuang Shangqing pill (NHSQP), composed of 19 TCMs, is used to illustrate this strategy. The fingerprint profiling of NHSQP by HPLC/qTOF-MS resulted in the characterization of 190 compounds, comprising 47 unambiguously identified by reference standard comparison. A CCDS containing 60 characteristic components was constructed by analyzing the MS spectral differentiation of the crude drugs, a laboratory-made NHSQP powder, and negative control preparations. With the established CCDS, it was possible to simultaneously monitor 16 out of the 19 drugs involved in NHSQP. Subsequently, 26 NHSQP samples from different vendors were evaluated by the qualitative and semi-quantitative analyses of their LC/MS fingerprint data. The 60 characteristic components were detected in all of the NHSQP samples, which demonstrated their authenticity. When compared with the standard sample No. 3, however, 15 of the NHSQP samples exhibited inferior quality. Samples No. 21 and No. 13 differed significantly based on a PCA score plot, and the components responsible for the differentiation were confirmed to originate from different TCMs. This strategy is a powerful and easy method to implement and provides a potential approach to establishing the holistic quality control of complex TCM preparations.

Comparative pharmacokinetics study after oral administration of geniposide in normal rats and adjuvant-induced arthritis rats by UPLC-MS/MS

A simple and rapid ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method for quantitative analysis of geniposide (GE) in rat plasma was developed, validated and applied to determine the level of GE in rat plasma after oral administration of GE in adjuvant-induced arthritis (AA) and normal rats. The investigation showed that there were significant differences in the groups between the normal rat and AA rat in pharmacokinetics parameters, such as the area under the time versus drug concentration curve (AUC(0-∞)) (3.77 ± 0.68 versus 2.27 ± 0.42, p < 0.05), the apparent volume of distribution (V) (140.41 ± 2.07 versus 136.51 ± 1.03, p < 0.05), the mean residence time (MRT) (3.98 ± 0.90 versus 3.80 ± 0.50, p < 0.05) and the clearance from the total body (CL) (16.10 ± 2.87 versus 26.44 ± 4.94, p < 0.05). The results indicated that AA could alter the pharmacokinetics of the drug and these experimental findings could be useful for the further study of the clinical applications of GE.

Analyses of the iridoid glucoside dimers in Paederia scandens using HPLC-ESI-MS/MS

INTRODUCTION

Many dimers consisting of structurally similar monomers are difficult to be identified even using NMR. Rapid structural identification of iridoid glycoside dimers, especially isomeric dimers in a complicated matrix, remains desirable.

OBJECTIVE

To develop a rapid, sensitive analytical method for structural elucidation of trace iridoid glycoside isomers in a complicated extract.

METHODS

Three isomeric iridoid glucoside dimers, paederoscandoside, saprosmoside E and saprosmoside D, were isolated and further analysed by electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in positive-ion mode. Energy-resolved mass spectrometry (ERMS) was used to provide information on the relative intensity of ions versus collision energy. The crude extract of Paederia scandens was analysed by HPLC-ESI-MS/MS.

RESULTS

The relative abundance of product ions in the MS/MS spectra from ammonium adduct ions varied greatly for the three isomers. The energy-resolved experiments enhanced differences among the three isomers. A total of 13 iridoid glucoside dimers (three groups of isomers) in the extract of P. scandens were identified or tentatively characterised by using HPLC-ESI-QTOF based on the tandem mass spectra of references.

CONCLUSION

Linkage sites between different hydroxyl groups on the sugar and carboxyl groups for the three groups of isomers are confirmed. The reason for fragmentation differences might be that cleavage of the glycosidic bond accompanies the active H in vicinal hydroxyl rearrangement. The MS method is a useful tool for the analysis of isomers, especially trace isomers in a complicated extract.

Rapid Analysis of the Main Components of Glycyrrhizae Uralensis Fisch by UPLC/Q-TOF-MS

A rapid method for analysis of the main components of Radix Glycyrrhizae (RG) was developed using ultra-performanceliquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Previous study demonstrated that RG had antivirus, antioxidant，anti-tumor and other bioactivities. The separation analysis was performed on Waters Acquity UPLC system and the accurate mass of molecules and their fragment ions were determined by Q-TOF MS. Fourty compounds including triterpenoid saponins, flavonoid glycosides and flavonoid aglycones,coumarins, were identified and tentatively deduced on the basis of their element compositions, MS/MS data and relevant literatures. The results demonstrated that triterpenoid saponins, flavonoid glycosides and flavonoid aglycones were the main constituents of RG. Furthermore, an effective and rapid pattern was established allowing for comprehensive and systematic characterization of the complex samples.

Characterization and identification of saponins in Achyranthes bidentata by rapid-resolution liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

A rapid-resolution liquid chromatography (RRLC) method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) has been developed for analysis of oleanane-type triterpenoid saponins in Achyranthes bidentata. Collision-induced dissociation techniques were used to fragment the precursor molecular ions and the resulting product ions. A retro-Diels-Alder rearrangement from the oleanane aglycone skeleton in the MS/MS process yielded characteristic fragment ions in positive ion mode. These characteristic ions were helpful in predicting the aglycone structure. Losses of monosaccharide sequences, presence of sugar-chain fragment ions, and cleavage of CO(2) were observed for important information on sugar types and attachment sequences. Fragmentation rules of three major groups of saponins from A. bidentata were summarized, and the possible fragmentation pathways were proposed. A total of 22 compounds including both the target and unknown oleanane-type triterpenoid saponins were rapidly screened and predicted in the herbal extract by the developed method. The RRLC-Q-TOF MS/MS method has provided a powerful approach for rapid separation, target screening and structural elucidation of oleanane-type saponins, and also opened perspectives for similar studies on other herbal medicines.

Fragmentation study of iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae by rapid resolution liquid chromatography with diode-array detection and electrospray ionization time-of-flight mass spectrometry

Rapid resolution liquid chromatography (RRLC) coupled with diode array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS) method was applied to the mass spectral study of a series of naturally occurring iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae, which provides higher speed and increased sensitivity without loss of resolution. With dynamic adjustment as the key role of the fragmentor voltage and confirmed with authentic standards, valuable structural information regarding the nature of both the glycoside skeletons was thus obtained. Most compositions were found to possess organic acid moiety such as cinnamoyl, caffeoyl and ferulyol. Besides extensive fragmentation of the carbohydrate moiety, losses of the hydroxyl and glucose residue units showed in the spectra, permitting the exploration of the skeleton and the identity of substituents in the molecule. Ten major iridoid glycosides and 10 phenylpropanoid glycosides were identified or tentatively characterized based on their retention times, UV and TOF MS data. The major fragmentation pathways of PGs in Radix Scrophulariae obtained through the MS data was schemed systematically for the first time, which provides a reference for other PGs derivatives.

Fragmentation study of iridoid glycosides including epimers by liquid chromatography-diode array detection/electrospray ionization mass spectrometry and its application in metabolic fingerprint analysis of Gardenia jasminoides Ellis

A high-performance liquid chromatography-diode array detection/electrospray ionization mass spectrometry (HPLC-DAD/ESI-MS) method was applied to the characterization of ten iridoid glycosides in Gardenia jasminoides Ellis, a traditional Chinese medicine. During the process of structural elucidation, two groups of isomers including two epimers were structurally characterized and differentiated according to their distinctive fragmentation patterns which were closely related to their isomeric differentiations. Subsequently, the major compounds were purified by multi-dimensional chromatography and semi-preparative HPLC and the structure identification was confirmed with NMR techniques. The major fragmentation pathways of iridoid glycosides in Gardenia jasminoides Ellis obtained through the MS data were schemed systematically, which provided the best sensitivity and specificity for characterization of the iridoid glycosides especially the isomers so far. Based on the fragmentation patterns of iridoid glycosides concluded, seven major iridoid glycosides were characterized in rat plasma after intravenous administration of Gardenia jasminoides Ellis.

Rapid Analysis of the Main Components of the Total Glycosides of Ranunculus japonicus by UPLC/Q-TOF-MS

A rapid method for the analysis of the main components of the total glycosides of Ranunculus japonicus (TGOR) was developed using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). The separation analysis was performed on a Waters Acquity UPLC system and the accurate mass of molecules and their fragment ions were determined by Q-TOF MS. Twenty compounds, including lactone glycosides, flavonoid glycosides and flavonoid aglycones, were identified and tentatively deduced on the basis of their elemental compositions, MS/MS data and relevant literature. The results demonstrated that lactone glycosides and flavonoids were the main constituents of TGOR. Furthermore, an effective and rapid pattern was established allowing for the comprehensive and systematic characterization of the complex samples.