Study on the metabolites of betulinic acid in vivo and in vitro by ultra high performance liquid chromatography with time-of-flight mass spectrometry.

Betulinic acid is a triterpenoid organic acid with remarkable antitumor properties and is naturally present in many fruits, condiments and traditional Chinese medicines. Currently, a strategy was developed for the identification of metabolites following the in vivo and in vitro biotransformation of Betulinic acid with rat intestinal bacteria utilizing ultra high performance liquid chromatography with time-of-flight mass spectrometry with polymeric solid-phase extraction. As a result, 46 metabolites were structurally characterized. The results demonstrated that Betulinic acid is universally metabolized in vivo and in vitro, and Betulinic acid could undergo general metabolic reactions, including oxidation, methylation, desaturation, loss of O and loss of CH2 . Additionally, the main metabolic pathways in vivo and in vitro were determined by calculating the relative content of each metabolite. This is the first study of Betulinic acid metabolism in vivo, whose results provide novel and useful data for better understanding of the safety and efficacy of Betulinic acid.

UPLC-Q-TOF-MS/MS-guided dereplication of Pulsatilla chinensis to identify triterpenoid saponins.

INTRODUCTION: Triterpenoid saponins are the major bioactive constituents of Pulsatilla chinensis, playing an important role in various biological activities such as anti-tumour, cognition-enhancing, anti-biosis, anti-inflammatory, hypoglycemic and immunological adjuvant. OBJECTIVE: To establish a systematic strategy based on ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) for the efficient characterisation and identification of triterpenoid saponins in crude extracts from Pulsatilla chinensis. METHODOLOGY: In this work, the strategy includes two aspects: (1) positive mode: by target screening, we can deduce the aglycone type and the composition of sugar moiety according to the fragment ions; untargeted screening includes four steps, find unknown, formula finder, ChemSpider search and MS/MS identification; (2) negative mode: according to the MS/MS spectra, the composition of sugar chain bonded to C-28 is inferred reasonably. The extract of Pulsatilla chinensis was separated within 60 min on a C18 column and eluted with methanol and water both containing 0.1% formic acid. RESULTS: As a result, a total of 22 triterpenoid saponins (11 pairs of isomers) with four aglycone skeletons were tentatively identified or elucidated in crude extracts from Pulsatilla chinensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data. CONCLUSION: This study provides an efficient analysis strategy to rapidly identify the triterpenoid saponins in Pulsatilla species even in traditional Chinese medicines.

Discrimination and Chemical Phylogenetic Study of Four Pulsatilla Herbs Using UPLC-ESI-MS/MS Combined with Hierarchical Cluster Analysis.

A tissue-smashing based ultra-rapid extraction coupled with ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS) method was developed to determine 10 major triterpenoid saponins from Pulsatilla herbs. Compound 4 was characterized as betulinic acid glycoside 3-O-α-arabinopyranosyl-28-O-ß-glucopyranosyl-23-hydroxy with HR-ESI-MS, 1H-NMR and 13C-NMR experiment. The MS spectra result showed that the ionization of compound 4 was more efficient in the positive mode. Meanwhile, the ions at m/z 789.6 and m/z 627.5 were selected as precursor and product ion for the determination, respectively. The chromatographic separation was carried out on a Phenomenex Kinetex C18 column using a gradient mobile phase system composed of 0.1% formic acid both in methanol and water at a flow rate of 0.4 mL/min. The detection was performed by multiple reaction monitoring mode, using electrospray ionization in the positive and negative mode. The total run time was 6 min. The calibration curves possessed good linearity with all coefficients higher than 0.9987. The intra- and interday precisions were no more than 4.9%, and the average recoveries were from 97.6% to 103.4% with RSD <4.7%. Moreover, hierarchical cluster analysis was performed to compare and discriminate the Pulsatilla herbs based on the quantitative data. The hierarchical cluster analysis results demonstrated that Pulsatilla chinensis, Pulsatilla cernua, Pulsatilla dahurica, Pulsatilla turczainovii samples could be easily discriminated from each other based on the contents of triterpenoid saponins and the established method is feasible for quality control of Pulsatilla herbs.

Simultaneous determination of 12 active components in the roots of Pulsatilla chinensis using tissue-smashing extraction with liquid chromatography and mass spectrometry.

Ultra high performance liquid chromatography coupled with mass spectrometry and combining a tissue-smashing extraction technique was developed for the simultaneous quantitative analysis of 12 compounds in the roots of Pulsatilla chinensis. Among them, compound 6 was characterized and accurately quantified in this herb for the first time. The parameters of extraction condition were simultaneously optimized with a Box-Behnken design and Derringer's function. The optimized conditions were as follows: sample quantity of 0.5 g, ethanol concentration of 70%, and extraction time of 200 s. Multiple-reaction monitoring scanning was employed for the quantification between positive and negative mode in a single run of 6 min. Full validation of the method was carried out, and the results indicated that the method was rapid, specific, and reliable. The developed method was successfully applied to quantify the 12 compounds in 33 batches of P. chinensis from different provinces. Moreover, the principal component analysis was performed to compare the P. chinensis collected from different provinces of China based on quantitative data and the results indicated that the content of compounds could be used to differentiate the origins of P. chinensis. These results demonstrated that this method is feasible and reliable for the quality control of P. chinensis.

[Simultaneous determination of 4 diterpenoids in Rabdosia japonica var.glaucocalyx by HPLC-ESI-MS/MS and cluster analysis].

A quick HPLC-ESI-MS/MS method was established for simultaneous determination of four major diterpenoids in Rabdosia japonica var.glaucocalyx, including glaucocalyxin A, oridonin, hebeirubesensin and enmenol. Analysis was performed on an Agilent ZORBAX SB-C18(4.6 mm×250 mm, 5 µm ) column eluted in a gradient program with methanol and water. The flow rate was 0.8 mL•min⁻¹. Multiple reaction monitoring (MRM) scanning mode was performed in negative ion switching mode to apply for the quantitative determination. The calibration curves for the above four compounds were linear in corresponding injection amount. The average recoveries of the compounds ranged from 92.40% to 105.9%, with RSDs of 1.7%-6.5%. The method is simple, rapid, accurate with good repeatability, which can provide a reference for overcalling evaluation the quality of R. japonica var.glaucocalyx. The result of cluster analysis- showed that the quality of R. japonica glaucocalyx var. greatly varied between areas and parts.

[Simultaneous determination of 3 phenolic acids in Usnea by HPLC-ESI-MS/MS].

A quick HPLC-ESI-MS/MS method was established for simultaneous determination of three chemical compositions in Usnea, including usnic acid, diffractaic acid, and ramalic acid. The separation was performed on a chromatographic column of Agilent ZORBAX SB-C, (4.6 mm x 250 mm, 5 µm), and the mobile phase was methanol (0.05% formic acid)-0.05% formic acid solution (4 mmol ammonium acetate), with an isocratic elution at a flow rate of 0.8 ml · min⁻¹. Multiple reaction monitoring scanning mode (MRM) was performed combined with the ion switching technology in positive and negative ion switching mode to apply for the quantitative determination. The calibration curves for the above three compounds were linear in corresponding injection amount. Their average recoveries were 95.0%-105.1%, with RSDs of 1.1%-5.2%. The method was simple, rapid, accurate with high repeatability, which could provide a reference for overcalling evaluation the quality of Usnea.

A comparative study on the pharmacokinetics of a traditional Chinese herbal preparation with the single herb extracts in rats by LC-MS/MS method.

The Er-Mu preparation (EMP) is a well-known traditional Chinese prescription that has been clinically employed for the treatment of asthma and bronchial inflammation for hundreds of years. Neomangiferin, mangiferin, peimine, peiminine, timosaponin BII and timosaponin AIII are the major active ingredients of EMP for their anti-inflammatory or anti-asthmatic effects. The aim of this study was to investigate the pharmacokinetics of the target compounds from the recipe of EMP and the single herb extracts of Anemarrhenae asphodeloides Bge. (ARR) and Fritillariae cirrhosae D.Don (FCB), and the influence of compatibility on the pharmacokinetics of the main active ingredients. The rats were randomly assigned to three groups and orally administered with the recipe of EMP and the single herb extracts of ARR and FCB, respectively. The concentrations of the target compounds in rat plasma were determined by an optimal liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) and multiple reaction monitoring (MRM) with a multi-switching monitoring mode coupled with simple protein precipitation method, and the main pharmacokinetic parameters were estimated. Significant differences (p<0.05) were found in the pharmacokinetic parameters of neomangiferin, mangiferin, peimine and peiminine between the single ARR or FCB extract and the combination treatment (p<0.05). The developed HPLC-ESI-MS method by switching positive and negative ESI sources in a single run was successfully applied to study the pharmacokinetics of six compounds in SD rat, which was powerful in terms of sensitivity, selectivity, time savings and solvent consumption in the quantitative analysis of complex herbal medicines. It was surmised that formula compatibility could significantly influence the pharmacokinetics of EMP and our study has preliminarily elucidated the priority in the compatible administration of EMP based on pharmacokinetic studies.