Rapid profiling and structural characterization of bioactive compounds and their distribution in different parts of Berberis petiolaris Wall. ex G. Don applying hyphenated mass spectrometric techniques

Pancreatic beta cell regenerative potential of Zanthoxylum chalybeum Engl. Aqueous stem bark extract

ETHNOPHARMACOLOGICAL RELEVANCE

Zanthoxylum chalybeum Engl. is endemic to Africa and has been used traditionally to treat diabetes mellitus. Moreover, its pharmacological efficacy has been confirmed experimentally using in vitro and in vivo models of diabetes. However, the effects of Z. chalybeum extracts and its major constituent compounds on beta cell and islet regeneration are not clear. Further, the mechanisms associated with observed antidiabetic effects at the beta cell level are not fully elucidated.

AIM OF THE STUDY

We determined the beta cell regenerative efficacy of Z. chalybeum aqueous stem bark extract, identified the chemical compounds in Z. chalybeum aqueous stem bark extracts and explored their putative mechanisms of action.

MATERIALS AND METHODS

Phytochemical profiling of the Z. chalybeum extract was achieved using ultra high-performance liquid chromatography hyphenated to high-resolution mass spectrometry. Thereafter, molecular interactions of the compounds with beta cell regeneration targets were evaluated via molecular docking. In vitro, effects of the extract on cell viability, proliferation, apoptosis and oxidative stress were investigated in RIN-5F beta cells exposed to palmitate or streptozotocin. In vivo, pancreas tissue sections from streptozotocin-induced diabetic male Wistar rats treated with Z. chalybeum extract were stained for insulin, glucagon, pancreatic duodenal homeobox protein 1 (Pdx-1) and Ki-67.

RESULTS

Based on ligand target and molecular docking interactions diosmin was identified as a dual specificity tyrosine-phosphorylation-regulated kinase 1A (Dyrk1A) inhibitor. In vitro, Z. chalybeum augmented cell viability and cell proliferation while in palmitate-pre-treated cells, the extract significantly increased cell activity after 72 h. In vivo, although morphometric analysis showed decreased islet and beta cell size and density, observation of increased Pdx-1 and Ki-67 immunoreactivity in extract-treated islets suggests that Z. chalybeum extract has mild beta cell regenerative potential mediated by increased cell proliferation.

CONCLUSIONS

Overall, the mitogenic effects observed in vitro, were not robust enough to elicit sufficient recovery of functional beta cell mass in our in vivo model, in the context of a sustained diabetic milieu. However, the identification of diosmin as a potential Dyrk1A inhibitor merits further inquiry into the attendant molecular interactions.

Rapid separation and identification of 96 main constituents in Huanglian Jiedu decoction via ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer

Huanglian Jiedu decoction is a widely used traditional Chinese medicine with a broad spectrum of therapeutic effects, including heat clearing, detoxification, and attenuation of inflammation. However, the composition of Huanglian Jiedu decoction is still unclear due to its complexity and limitations of analytical methods. In this study, we established a fast and reliable analytical method based on ultra-performance LC-Orbitrap Fusion Tribrid mass spectrometer for high-speed separation and structural identification of multiple compounds in Huanglian Jiedu decoction. The analysis was carried out using a Hypersil GOLD C18 column (2.1 × 100 mm, 1.9 μm) with gradient elution coupled to a high-definition mass spectrometer system operating in both positive and negative ESI modes. According to the chromatographic retention time, precise molecular weight, fragment ion peaks, and published data, the main chromatographic peaks were attributed to specific molecules whose chemical structures were determined. In total, 96 components were identified, including 34 flavonoids and their glycosides, 23 alkaloids, 18 organic acids, 13 terpenoids, and 8 miscellaneous compounds. This study revealed the detailed chemical composition of Huanglian Jiedu decoction, which is of great importance for quality control and further pharmacological and mechanistic studies.

Effect of Gut Microbiota on the Metabolism of Chemical Constituents of Berberis kansuensis Extract Based on UHPLC-Orbitrap-MS Technique

The dried stem bark of Berberis kansuensis is a commonly used Tibetan herbal medicine for the treatment of diabetes. Its main chemical components are alkaloids, such as berberine, magnoflorine and jatrorrhizine. However, the role of gut microbiota in the in vivo metabolism of these chemical components has not been fully elucidated. In this study, an ultra-high performance liquid chromatography method coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) technology was applied to detect and identify prototype components and metabolites in rat intestinal contents and serum samples after oral administration of a B. kansuensis extract. A total of 16 prototype components and 40 metabolites were identified. The primary metabolic pathways of the chemical components from B. kansuensis extract were demethylation, desaturation, deglycosylation, reduction, hydroxylation, and other conjugation reactions including sulfation, glucuronidation, glycosidation, and methylation. By comparing the differences of metabolites between diabetic and pseudo-germ-free diabetic rats, we found that the metabolic transformation of some chemical components in B. kansuensis extract such as bufotenin, ferulic acid 4-O-β-D-glucopyranoside, magnoflorine, and 8-oxyberberine, was affected by the gut microbiota. The results revealed that the gut microbiota can affect the metabolic transformation of chemical constituents in B. kansuensis extract. These findings can enhance our understanding of the active ingredients of B. kansuensis extract and the key role of the gut microbiota on them.

Cyclopeptide alkaloids from Discaria chacaye (Rhamnaceae) as result of symbiosis with Frankia (Actinomycetales)

Cyclopeptide alkaloids with different biological activities are present in plants of the family Rhamnaceae. Plants of this family grow in a symbiotic relationship with aerobic Gram-positive actinomycetes belonging to the genus Frankia . This goal of this research was a study of the comparative profile of alkaloids present in Discaria chacaye and to establish a connection between the presence or absence of Frankia sp. and the alkaloids. In addition, insecticidal activities of the alkaloidal extract were examined. A total of 24 alkaloids were identified, of which 12 have a benzylisoquinoline skeleton, 9 were cyclopeptides, 2 isoquinolines, and 1 an aporphine. The presence of cyclopeptide alkaloids is associated with Frankia nodules in the plant root. The alkaloid extracts showed insecticidal activity with mortality dose-dependence and LD 50 values between 44 to 71 µg/mL.

Attenuation of obesity related inflammation in RAW 264.7 macrophages and 3T3-L1 adipocytes by varanadi kashayam and identification of potential bioactive molecules by UHPLC-Q-Orbitrap HRMS

Obesity is associated with chronic low-grade inflammation, characterised by the up-regulation of pro-inflammatory cytokines in obese adipose tissue. In this study, 3T3-L1 CM enhanced TNF-α and IL-1β in RAW 264.7 cells compared with LPS treated cells. However, treatment with Varanadi kashayam suppressed the inflammatory changes associated with RAW 264.7 cells. Subsequently, RAW CM used to stimulate adipocytes, resulting in decreased intracellular lipid content and reduced adipogenic markers after Varanadi kashayam treatment. The chemical profiling of Varanadi kashayam using UHPLC-Q-Orbitrap-HRMS identified 194 compounds by comparing their retention time, the experimentally measured exact mass of precursor, and fragmented ions, and fragmentation pattern with spectral library and reported literature. Collectively, Varanadi kashayam act as a potent anti-inflammatory and anti-adipogenic agent that could disrupt the crosstalk between adipocytes and macrophages. Hence it could be a better candidate for reducing inflammation associated with obese adipose tissue.

Differentiation, chemical profiles and quality evaluation of five medicinal Stephania species (Menispermaceae) through integrated DNA barcoding, HPLC-QTOF-MS/MS and UHPLC-DAD

Stephania species is one of the alkaloid-rich genus of the family Menispermaceae. Most plants of the genus Stephania possess medicinal value, whose main components are alkaloids. However, the non-medical species are often mistakenly used as herbs because of the difficulty in identification of the species. A systematic method which involved the combination of DNA barcoding, HPLC-QTOF-MS/MS and UHPLC was established for differentiation, chemical profiles and quality evaluation of medicinal Stephania species. Firstly, twenty batches of Stephania species samples were classified into five Stephania species by DNA barcoding. Secondly, 114 alkaloids including 22 tetrahydroprotoberberines, 13 protoberberines, 27 aporphines, 13 benzylisoquinolines, 12 hasubanans, 3 morphines and 24 other alkaloids were clearly or tentatively identified. Thirdly, thirteen representative components were simultaneously detected by UHPLC-DAD to characterize the differences of chemical compositions among five Stephania species. In conclusion, this method was comprehensive and effective for identification, chemical profiles and quality evaluation of medicinal Stephania species. It will provide a basis for holistic quality evaluation of medicinal Stephania species.

Metabolomic profiling of Zanthoxylum species: Identification of anti-cholinesterase alkaloids candidates

The isolation of bioactive compounds from natural sources is a key step in drug discovery and development, however, this procedure is usually expensive and difficult due to the complexity and the limited amounts of the metabolites in the extracts. Thus, rational or targeting isolations are becoming more popular to reduce the bottlenecks in bioactive natural products research. In this study, we used a LC-MS-based metabolomic approach and biochemometric statistical tools (PCA and OPLS-DA) to identify potential anti-cholinesterase alkaloids predictors in Zanthoxylum genus (Rutaceae). For this purpose, 41 alkaloid extracts from nine Colombian Zanthoxylum species were screened by UHPLC-UV-HRMS and inhibitory activity against Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE). Based on the screening results, a multivariate statistical analysis (MVA) and selection of anti-cholinesterase candidates were performed using the S-plot from the OPLS-DA model. The supervised analysis (OPLS-DA) paring the anti-cholinesterase screening and LC-HRMS data showed at least 11 ChE inhibition markers which could have contributed in the differentiation of active and inactive extracts. The predictors were tentatively identified by comparing chromatographic retention times (R_t) and accurate mass and MS² fragmentation patterns. In general, the inhibition markers correspond to four types of isoquinoline alkaloids: tetrahydroprotoberberines, protoberberines, dihydrobenzophenanthridines and benzophenanthridines. The most active extracts from Z. schreberi and Z. monophylum showed the highest presence of berberine and chelerythrine, previously reported as cholinesterase inhibitors. Thus, to validate the results of the OPLS-DA model, three alkaloids from the bark of Z. schreberi (identified as berberine, chelerythrine and columbamine) were bio-directed isolated, and all of them showed strong inhibition against both enzymes. These findings support our statistical models and contribute to the rational search of anticholinesterase alkaloids. Therefore, LC-MS-based metabolomic approach combined with chemometric statistical analysis are shown as useful tools for the isolation of targeted bioactive natural products, contributing to improve the research and development stages of lead compounds.

Identification of structurally diverse alkaloids in Talguenea quinquinervia (gill. Et hook) by liquid chromatography/electrospray ionisation tandem mass spectroscopy and insecticidal activity

INTRODUCTION

Talguenea quinquinervia has been used in folk medicine and to dye wool, and the main constituents are alkaloids and triterpenes. Identification of these type of compounds in this specie is a necessary step to understand the biological properties.

OBJECTIVE

To evaluate the relationship between the chemical composition of root from T. quinquinervia and its insecticidal properties using liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS).

METHODS

Alkaloids were extracted using Soxhlet extraction with methanol. Total extract was partitioned at pH 2 and 12 to enrich alkaloid constituents and to remove interferences. The separation of alkaloids in the Talguenea extract was performed on a C18 column using gradient elution and their tandem mass spectra were obtained by quadrupole time-of-flight tandem mass spectrometry (QTOF-MS/MS) to perform accurate mass measurements of fragment ions for the alkaloid constituents.

RESULTS

Several types of alkaloids were separated and identified by LC-ESI-MS/MS. The structural assignment of individual alkaloids was performed based on convergence of MS/MS spectral data, pH partitioning behaviour, LC retention behaviour, and accurate mass measurements. The pH partition of the extract provided structural information about unknown alkaloids extracted from T. quinquinervia. A total of 20 compounds were identified and tentatively characterised, and of these 15 alkaloids were reported for the first time in the investigated T. quinquinervia.

CONCLUSION

The chemical profiling of alkaloids in T. quinquinervia with different origins was performed for the first time and provided diagnostic ions for diverse alkaloids in T. quinquinervia. Insecticidal activity observed can be explain by the presence of alkaloid and pentacyclic triterpenes on the fractions assayed.

Analysis of potential anti-aging beverage Pru, a traditional Cuban refreshment, by desorption electrospray ionization-mass spectrometry and FTICR tandem mass spectrometry

Aging has been established as a major risk factor for prevalent diseases and hence, the development of anti-aging medicines is of great importance. Recently, herbal fermented beverages have emerged as a promising source of potential anti-aging drug. Pru, a traditional Cuban refreshment produced by decoction and fermentation of multispecies plants with sugar, has been consumed for many years and is claimed to have multiple medicinal properties. Besides the traditional method, Pru is also manufactured industrially. The present study analyzed the major components of both traditional Pru (TP) and industrial Pru (IP) to reveal their potential application in promoting the health span. We performed desorption electrospray ionization-mass spectrometry (DESI-MS) and acquired mass spectra by scanning over the 50–1200 m/z range in both positive and negative ion modes. Fourier transform ion cyclotron resonance (FTICR) tandem mass spectrometry (MS/MS) was performed for validating the compound assignments. Three important compounds were identified by comparing the MS and MS/MS spectra with reported literature and the online database. One of the identified compounds, gluconic acid, was found to be the most abundant shared metabolite between TP and IP whereas the other two compounds, magnoflorine and levan were exclusively detected in TP. The present study is the first report of component profiling in Cuban traditional and industrial Pru using DESI-MS and FTICR MS/MS, and reveals the potential application of Pru as a health-promoting agent.

Size-tunable Au@Ag nanoparticles for colorimetric and SERS dual-mode sensing of palmatine in traditional Chinese medicine

Palmatine is a protoberberine alkaloid separated from several plants and application as an anti-inflammatory and antibacterial agent in the therapy of gastrointestinal and genitourinary disorder. Thus, the fast quantification of palmatine is important in clinic medical assays. Herein, we report simple, fast and sensitive colorimetric visualization and surface-enhanced Raman spectroscopy (SERS) dual-mode detection of palmatine basing on bimetallic size tunable silver shell capped gold nanoparticles (Au@Ag NPs). Interesting, the best signals output for dual-mode sensing of palmatine were both 5 nm Ag shell thickness of Au@Ag NPs. Meanwhile, we found that the addition of NaHSO₄ significantly improves the aggregating sensitivity of Au@Ag NPs to trace palmatine. Upon exposure to 0.1 μM level palmatine, NaHSO₄-optimized Au@Ag NPs solution exhibits a highly sensitive color change from orange to green and rapid aggregation kinetics within the initial 5 min, which can directly be seen with the naked eye and monitored by UV-vis absorbance spectra. In addition, we measured palmatine by SERS with the excellent enhancement effect of Au@Ag NPs for further increase the sensitivity and selectivity. More importantly, other protoberberine alkaloids do not interfere with this dual-mode sensor due to the different interaction force between Au@Ag NPs and these alkaloids, and the applicability of the sensor is well demonstrated in real samples with satisfactory results. This provide a fast and simple assay for the rapid detection of palmatine in traditional Chinese medicine, the limit of detection (LOD) is 0.13 μM by the naked eye and 0.10 μM by UV-vis spectroscopy. Therefore, the size-tunable of NaHSO₄-optimized Au@Ag NPs can be used not only as a naked-eye sensor of palmatine, but also as a highly selective SERS probe.

Capillary-HPLC with tandem mass spectrometry in analysis of alkaloid dyestuffs - a new approach

Development of the identification method of alkaloid compounds in Amur cork tree as well as not examined so far Oregon grape and European Barberry shrubs are presented. The novel approach to separation of alkaloids was applied and the capillary-high-performance liquid chromatography (capillary-HPLC) system was used, which has never previously been reported for alkaloid-based dyestuffs analysis. Its optimization was conducted with three different stationary phases (unmodified octadecylsilane-bonded silica, octadecylsilane modified with polar groups and silica-bonded pentaflourophenyls) as well as with different solvent buffers. Detection of the isolated compounds was carried out using diode-array detector (DAD) and tandem mass spectrometer with electrospray ionization (ESI MS/MS). The working parameters of ESI were optimized, whereas the multiple reactions monitoring (MRM) parameters of MS/MS detection were chosen based on the product ion spectra of the quasi-molecular ions. Calibration curve of berberine has been estimated (y = 1712091x + 4785.03 with the correlation coefficient 0.9999). Limit of detection and limit of quantification were calculated to be 3.2 and 9.7 ng/mL, respectively. Numerous alkaloids (i.e., berberine, jatrorrhizine and magnoflorine, as well as phellodendrine, menisperine and berbamine) were identified in the extracts from alkaloid plants and silk and wool fibers dyed with these dyestuffs, among them their markers.

Protective effect of Berberis aristata against peritonitis induced by carbapenem-resistant Escherichia coli in a mammalian model

OBJECTIVES

Berberis aristata is known to contain a variety of phenolic compounds contributing to its holistic capability of mitigating bacterial multidrug resistance.

METHODS

B. aristata stem bark extract was prepared and was characterised using liquid chromatography-mass spectrometry (LC-MS). The antimicrobial efficacy of the extract against carbapenem-resistant Escherichia coli was assessed in vivo in an animal model using Sprague Dawley rats. Microbial counts in blood and urine, physical health status, haematological and biochemical analysis of blood, and histopathology of the kidney were assessed as the study endpoints.

RESULTS

An aquo-alcoholic extract of B. aristata (PTRC-2111-A) was found to effectively manage peritonitis induced by carbapenem-resistant E. coli in a rat model at a single post-exposure prophylactic dose of 0.5mg/kg body weight (BW). The extract was also found to show a no observed adverse effect level (NOAEL) up to a dose of 2000mg/kg BW. Physical, immunological, haematological, biochemical and histopathological aberrations were found to be restored to normal in the herbal-treated group at a dose of 0.5mg/kg BW.

CONCLUSIONS

The antimicrobial and hepatorenal protective ability of PTRC-2111-A could be attributed to the presence of isoquinoline alkaloids.

Tissue-specific metabolite profiling of benzylisoquinoline alkaloids in the root of Macleaya cordata by combining laser microdissection with ultra-high-performance liquid chromatography/tandem mass spectrometry

RATIONALE

Tissue-specific metabolite profiling helps to find trace alkaloids masked during organ analysis, which contributes to understanding the alkaloid biosynthetic pathways in vivo and evaluating the quality of medical plants by morphology. As Macleaya cordata contains diverse types of benzylisoquinoline alkaloids (BIAs), the alkaloid metabolite profiling was carried out on various tissues of the root.

METHODS

Laser microdissection with fluorescence detection was used to recognize and dissect different tissues from the root of M. cordata. Ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry was applied to analyze the trace alkaloids in tissues. These detected alkaloids were elucidated using their accurate molecular weights, MS/MS data, MS fragmentation patterns and the known biosynthetic pathways of BIAs. Finally, the distribution of alkaloids in dissected tissues and whole sections was mapped.

RESULTS

Forty-nine alkaloids were identified from five microdissected tissues, and 24 of them were detected for the first time in M. cordata. Some types of alkaloids occurred specifically in dissected tissues. More alkaloids were detected in the cork and xylem vascular bundles which emit strong fluorescence under fluorescence microscopy. Some of the screened alkaloids were intermediates in sanguinarine and chelerythrine biosynthetic pathways, and others were speculated to be involved in the new branches of biosynthetic pathways.

CONCLUSIONS

The integrated method is sensitive, specific and reliable for determining trace alkaloids, which is also a powerful tool for metabolite profiling of tissue-specific BIAs in situ. The present findings should contribute to a better understanding of the biosynthesis of BIAs in M. cordata root and provide scientific evidence for its quality evaluation based on morphological characteristics. Copyright © 2016 John Wiley & Sons, Ltd.

Distribution and Discrimination Study of Bioactive Compounds from Berberis species using HPLC-ESI-QTOF-MS/MS with Principle Component Analysis

Berberis species have been used extensively as raw material in various herbal medicines. In this work, a fast and sensitive method based on reversed-phase high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (HPLC-ESI-QTOF-MS/MS) was used to assist the distribution and discrimination study of bioactive compounds from Berberis species such as B. aristata, B. asiatica, B. chitria, B. jaeschkeana, B. koehneana, B. lyceum, B. petiolaris and B. pseudoumbellata. The HPLC separation was performed on a Thermo Betasil C8 column (250 mm x 4.5 mm, 5μ) using gradient elution with a mobile phase of 0.1% aqueous solution of formic acid (v/v) and acetonitrile. The high resolution (HR) and collision induced dissociation (CID) mass spectrometry experiments were conducted in order to provide molecular-mass information and MS/MS fragmentation patterns of the compounds for structural elucidation. A total of 59 compounds were tentatively identified and characterized including three acids, forty-one alkaloids and twelve flavonoids using seventeen reference standards for authentication. Principle component analysis (PCA) was also applied to discriminate eight Berberis species according to their plant parts i.e., leaf, stem and root. The highest total content of identified compounds was detected in the root of all the Berberis species wherein alkaloids were predominant.

Analysis of isoquinoline alkaloids from Mahonia leschenaultia and Mahonia napaulensis roots using UHPLC-Orbitrap-MSn and UHPLC-QqQLIT-MS/MS

Mahonia leschenaultia (ML) and Mahonia napaulensis (MN) are less known and unexplored medicinal plants of the family Berberidaceae. They are used by the Todas of Nilgiris in their religious and medical practices but chemically less identified. Hence, we decided to do extensive phytochemical analysis to explore the potential of these plant extracts. An ultrahigh performance electrospray tandem mass spectrometry (UHPLC–ESI–MS/MS) method was successfully developed for qualitative analysis of the bioactive components in Mahonia species using Orbitrap Velos Pro mass spectrometer. Sixteen compounds were identified by comparison of their retention times and mass spectra (MS) with authentic standards and reported literature. Multi-stage mass spectra (MS^2–8) for the identification of protoberberine and aporphine alkaloids showed the sequential expulsion of all the substituents attached with their basic skeleton followed by CO loss. Eight of the identified compounds (berberine, jatrorrhizine, palmatine, magnoflorine, isocorydine, glaucine, tetrahydropalmatine and tetrahydroberberine) were simultaneously determined by another UHPLC–ESI–MS/MS method under the multiple reactions monitoring (MRM) mode quantitatively using triple quadrupole linear ion trap mass spectrometer. The analytical method was validated for 8 bioactive compounds with overall recovery in the range 98.5%–103.6% (RSD≤2.2%), precise (RSD≤2.07%) and linear (r≥0.9995) over the concentration range of 0.5–1000 ng/mL and successfully applied in ML and MN roots, which suggests the suitability of the proposed approach for the routine analysis of Mahonia species and their quality control.

Identification of Alkaloids in Stephania hainanensis by Liquid Chromatography Coupled with Quadrupole Time-of-flight Mass Spectrometry

INTRODUCTION

Plants in the genus Stephania can produce diverse bioactive alkaloids. Stephania hainanensis is a medicinal plant that contains effective alkaloids. However, only 10 alkaloids have been reported in this species.

OBJECTIVE

To characterise the alkaloids in Stephania hainanensis using liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS/MS).

METHODS

An LC-QTOF-MS/MS method was developed for structural characterisation of the alkaloids in Stephania hainanensis. The chromatographic separation was performed on a phenyl column with gradient elution, and the tandem mass spectra were obtained by using an electrospray ionisation (ESI) interface in positive ionisation mode. Compound identification was based on the exact masses, fragmentation pathways, retention behaviours and related botanical biogenesis.

RESULTS

A total of 37 tetrahydroprotoberberine-, quaternary protoberberine-, aporphine-, proaporphine-, benzylisoquinoline- or bisbenzylisoquinoline-type alkaloids were identified or tentatively identified in a single LC run. Twenty-seven of these alkaloids, including the benzylisoquinoline-type of alkaloids, have not been previously reported in Stephania hainanensis. The possible fragmentation pathways of different types of alkaloids were proposed. Besides the general fragmentations, the characteristic losses of CH3 N = CH2 were observed for the benzylisoquinoline and aporphine alkaloids with two methyl groups on the nitrogen.

CONCLUSION

The LC-QTOF-MS/MS method enabled profiling and rational, but tentative, identification of diverse alkaloids in Stephania hainanensis. The results obtained may be helpful for understanding the bioactivity of S. hainanensis and evaluating the quality of this plant. Copyright © 2016 John Wiley & Sons, Ltd.

Anti-hemolytic, hemagglutination inhibition and bacterial membrane disruptive properties of selected herbal extracts attenuate virulence of Carbapenem Resistant Escherichia coli

Expression of a multitude of virulence factors by multi-drug resistant microbial strains, e.g., Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria), is responsible for resistance against beta-lactam antibiotics. Hemolysin production and induction of hemagglutination by bacterial surface receptors inflicts direct cytotoxicity by destroying host phagocytic and epithelial cells. We have previously reported that Berberis aristata, Camellia sinensis, Cyperus rotundus Holarrhena antidysenterica and Andrographis paniculata are promising herbal leads for targeting Carbapenem resistant Escherichia coli. These herbal leads were analyzed for their anti-hemolytic potential by employing spectrophotometric assay of hemoglobin liberation. Anti-hemagglutination potential of the extracts was assessed by employing qualitative assay of visible RBC aggregate formation. Camellia sinensis (PTRC-31911-A) exhibited anti-hemolytic potential of 73.97 ± 0.03%, followed by Holarrhena antidysenterica (PTRC-8111-A) i.e., 68.32 ± 0.05%, Berberis aristata (PTRC-2111-A) i.e., 60.26 ± 0.05% and Cyperus rotundus (PTRC-31811-A) i.e., 53.76 ± 0.03%. Comprehensive, visual analysis of hemagglutination inhibition revealed that only Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) exhibited anti-hemagglutination activity. However, Andrographis paniculata (PTRC-11611-A) exhibited none of the inhibitory activities. Furthermore, the pair wise correlation analysis of the tested activities with quantitative phytochemical descriptors revealed that an increased content of alkaloid; flavonoids; polyphenols, and decreased content of saponins supported both the activities. Additionally, flow cytometry revealed that cell membrane structures of CRE were damaged by extracts of Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) at their respective Minimum Inhibitory Concentrations, thereby confirming noteworthy antibacterial potential of both these extracts targeting bacterial membrane; hemolysin and bacterial hemagglutination.

Analysis of phytochemical variations in dioecious Tinospora cordifolia stems using HPLC/QTOF MS/MS and UPLC/QqQLIT -MS/MS

INTRODUCTION

The stem of dioecious Tinospora cordifolia (Menispermaceae) is a commonly used traditional Ayurvedic medicine in India having several therapeutic properties.

OBJECTIVE

To develop and validate LC-MS methods for the identification and simultaneous quantitation of various secondary metabolites and to study metabolomic variations in the stem of male and female plants.

METHODS

Ethanolic extract of stems were analysed by HPLC/ESI-QTOF-MS/MS for rapid screening of bioactive phytochemicals. High resolution MS and MS/MS in positive ESI mode were used for structural investigation of secondary metabolites. An UPLC/ESI-QqQ(LIT) -MS/MS method in MRM mode was developed and validated for the simultaneous quantitation of five bioactive alkaloids.

RESULTS

Identification and characterisation of 36 metabolites including alkaloids, sesquiterpenes and phytoecdysteroids were performed using LC-MS and MS/MS techniques. The bioactive alkaloids such as jatrorrhizine, magnoflorine, isocorydine, palmatine and tetrahydropalmatine were successfully quantified in male and female plants. The mean abundances of magnoflorine jatrorrhizine, and oblongine were significantly (P < 0.05) higher in male plants while mean abundances of tetrahydropalmatine, norcoclaurine, and reticuline were significantly (P < 0.05) higher in female plants.

CONCLUSIONS

Phytochemicals in the stem of male and female Tinospora cordifolia showed significant qualitative and quantitative variations. LC-MS and MS/MS methods can be used to differentiate between male and female plants based on their chemical profiles and quantities of the marker bioactive alkaloids. This chemical composition difference was also evident during vegetative stage when there were no male and female flowers.

Profiling of Gallic and Ellagic Acid Derivatives in Different Plant Parts of Terminalia Arjuna by HPLC-ESI-QTOF-MS/MS

Terminalia arjuna is a medicinal plant used in ethnomedicine and the codified traditional medicine. A number of active constituents are reported, but there is no information on the whole range of gallic and ellagic acid derivatives present in this plant. A rapid and sensitive analytical method was developed using reverse phase high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) for qualitative analysis to determine the array of bioactive phytochemicals and their variations in different plant parts viz. bark, unripe fruit, ripe fruit, leaf, root and stem. Separation was performed on a Thermo Betasil C8 column (250 mm×4.5 mm, 5μm) with a mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min in 55 min. A wide range of constituents of T. arjuna were characterized and broadly grouped as 27 gallic acid and 52 ellagic acid derivatives.

Identification, characterization and distribution of monoterpene indole alkaloids in Rauwolfia species by Orbitrap Velos Pro mass spectrometer

Monoterpene indole alkaloids (MIAs) are medicinally important class of compounds abundant in the roots of Rauwolfia species (Apocynaceae). MIAs such as yohimbine (aphrodisiac agent) and reserpine (antihypertensive, tranquilizer) are the official drugs included in Model List of Essential Drugs of World Health Organization (WHO). Therefore, we have attempt to identify and characterize the MIAs in the crude extracts of six Rauwolfia species using ultrahigh-performance liquid chromatography coupled with Orbitrap Velos Pro hybrid mass spectrometer. The identity of the MIAs were construed using the high resolution tandem mass spectrometry (HRMS/MS) spectra of standard compounds 'yohimbine' and 'reserpine' in higher energy collisional dissociation (HCD) and collision-induced dissociation (CID) modes. The diagnostic fragment ions found in HCD mode was highly affected by variation of normalized collision energy (NCE) and gave few product ions ('C-F') while CID produced intense and more diagnostic product ions ('A-F'). Consequently, CID-MS/MS mode provided significantly more structural information about basic skeleton and therefore the recommended mode for analysis of MIAs. Furthermore, six diagnostic fragmentation pathways were established by multi-stage mass analysis (MS(n) (n=5)) analysis which gave information regarding the substitution. Fragment ions 'A-F' revealed the number and position of substituents on indole and terpene moieties. The proposed diagnostic fragmentation pathways have been successfully applied for identification and characterization of MIAs in crude root extracts of six Rauwolfia species. Ten bioactive reserpine class of MIAs were tentatively identified and characterized on the basis of chromatographic and mass spectrometric features as well as HRMS/MS an MS(n) (n=4) analysis.

Structural characterization of flavonoid C- and O-glycosides in an extract of Adhatoda vasica leaves by liquid chromatography with quadrupole time-of-flight mass spectrometry

RATIONALE

Adhatoda vasica Nees is a well-known Ayurvedic medicinal plant, belonging to the family Acanthaceae. This study aims to seek identification and characterization of flavonoid C- and O-glycosides in the aqueous fraction of the plant leaves.

METHODS

A method was developed for simultaneous characterization of flavonoids and their glycosides using high-pressure liquid chromatography with quadrupole time-of-flight mass spectrometry (HPLC/ESI-QTOF-MS/MS). The chromatographic separation was carried on an Agilent Poroshell 120 EC-C18 column (4.6 × 150 mm, 2.7 µm) operated with 0.1% formic acid aqueous solution and methanol as the mobile phase.

RESULTS

The fragmentations of the studied [M-H](-) ions of C-glycosides were shown to be cross-ring cleavages of the glycoside moiety [M-H-(60/90/120)](-) whereas O-glycosides were shown to eliminate the sugar moiety (Y0 (-) or [Y0 -H](-) ) from the aglycone unit; 6-C-glycosides exhibited [M-H-18](-) , a characteristic ion, and also a higher abundance of (0,3) X6 or 8 ions in comparison to 8-C glycosides; flavonoid 6,8-di-C-glycosides exhibited cross-ring cleavages of the sugar attached to the C-6 position preferentially.

CONCLUSIONS

This method was successfully applied for analysis of flavonoids and their glycosides in Adhatoda vasica leaves. A total of 29 compounds were tentatively identified including 17 C-, nine O-glycosides and three flavonoids.

Rapid screening and distribution of bioactive compounds in different parts of Berberis petiolaris using direct analysis in real time mass spectrometry

Berberis petiolaris Wall. ex G. Don, an unexplored medicinal plant belonging to the family Berberidaceae, is a large deciduous shrub found in Western Himalaya between 1800–3000 m. Chemical profiling of fruit, leaf, root and stem was done by direct analysis in real time mass spectrometry followed by multivariate analysis for discrimination among the plant parts. The bioactive compounds, including magnoflorine, berberine, jatrorrhizine, thalifendine/berberrubine, demethyleneberberine, reticuline, 8-oxoberberine, N-methyltetrahydroberberine, tetrahydropalmatine, tetrahydroberberine and palmatine, were identified by their exact mass measurement and the corresponding molecular formula of each compound. A comparative study of distribution pattern for all these bioactive alkaloids showed qualitative and quantitative variations in different parts of B. petiolaris. Principal component analysis clearly discriminated each part of B. petiolaris plant.

Screening of tricyclic quinazoline alkaloids in the alkaloidal fraction of Adhatoda beddomei and Adhatoda vasica leaves by high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

RATIONALE

Adhatoda beddomei and Adhatoda vasica are popular Ayurvedic medicinal plants in India, belonging to the family Acanthaceae. Tricyclic quinazoline alkaloids are found to be the most abundant in these plants which are responsible for broad-spectrum medicinal properties. This study aims to seek identification and characterization of those alkaloids based on their fragmentation patterns.

METHODS

A method was developed to elucidate the main fragmentation pathways of tricyclic quinazoline alkaloids in positive ion mode using high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (HPLC/ESI-QTOF-MS/MS). Chromatographic separation was carried on a Supelco Discovery HS C18 column (15 cm × 4.6 mm, 3 µm) with 0.1% formic acid aqueous solution and acetonitrile as a mobile phase.

RESULTS

In full scan mass spectra, protonated molecules were observed for all the quinazoline alkaloids. Ring cleavages of the tricyclic quinazoline moiety were observed in MS(2) spectra and the characteristic ions provide valuable structural information of these alkaloids. Fragmentation pathways and fragment ion structures were proposed in two groups of quinazoline alkaloids.

CONCLUSIONS

The established fragmentation patterns have been successfully used to identify 23 tricyclic quinazoline alkaloids in the alkaloidal fraction of A. beddomei and A. vasica.