Metabolites study on 5-O-methylvisammioside in vivo and in vitro by ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

5-O-Methylvisammioside is one of major chromones of Radix Saposhnikoviae possessing definite pharmacological activities, but there are few reports with respect to the metabolism of 5-O-methylvisammioside. In this work, metabolites in vivo were explored in male Sprague-Dawley rats and in vitro investigated on rat intestinal bacteria incubation model and were identified by using ultra high performance liquid chromatography/quadrupole time-of-flight mass spectrometry. An online data acquisition method based on a multiple mass defect filter and dynamic background subtraction was developed to trace all probable metabolites. As a result, 26 metabolites in vivo (including 18, 15, 10, and 10 in rat urine, faece, bile, and blood) and 7 metabolites in vitro were characterized, respectively. Additionally, the main metabolic pathways in vivo and in vitro, including deglycosylation, deglycosylation + demethylation, deglycosylation + oxidation, N-acetylation, and sulfate conjugation, were summarized by calculating the relative content of each metabolite. The obtained results significantly enriched our knowledge about 5-O-methylvisammioside metabolism and will lead to a better understanding of its safety and efficacy.

Simultaneous detection of four flavonoids and two alkaloids in rat plasma by LC-MS/MS and its application to a comparative study of the pharmacokinetics between Abri Herba and Abri mollis Herba extract after oral administration.

Abri Herba and Abri mollis Herba both were important members of the Leguminosae family in southwestern China. Abri mollis Herba was often used as Abri Herba due to their proximity, but there are few studies on pharmacokinetics to compare their main identical active compositions. A sensitive and selective high-performance liquid chromatography with tandem mass spectrometry method in the positive/negative electrospray ionization switching mode was developed and validated for the simultaneous analysis of four flavonoids and two alkaloids in rat plasma. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of methanol and 0.5% acetic acid. The detection of the target compounds was conducted in multiple-reaction monitoring mode with a hybrid triple quadrupole linear ion trap mass spectrometer equipped with positive/negative ion-switching electrospray ion source. The differences in pharmacokinetics were discovered, which indicated that the substitution between them is some degree of irrationality. The validated method was successfully applied to pharmacokinetic study of the six components in male rat plasma after oral administration of Abri Herba and Abri mollis Herba extract and the results in the study would provide a useful guide for the clinical application of Abri Herba with those in Abri mollis Herba.

[Simultaneous determination of 8 constituents of Desmodii Styracifolii Herba in rat bile with HPLC-MS/MS and their excretion pharmacokinetics].

To establish a HPLC-MS/MS quantitative method for analysis of 8 constituents in rat bile. The method was applied in the biliary excretion study after oral administration of Desmodii Styracifolii Herba extract. The rat bile samples were collected during 0-1, 1-2, 2-4, 4-6, 6-8, 8-12, 12-24 h. Diamonsil C18column (4.6 mm×150 mm, 5 µm) was adopted and eluted with methanol and 0.01% acetic acid in a gradient mode. The flow rate was 0.8 mL•min⁻¹, and the column temperature was set at 40 ℃. The detection was carried out by a triple quadrupole linearion trap mass spectrometer in the negative ion mode with an electrospray source. Multiple reactions monitoring (MRM) mode was employed. The calibration curves showed a good linearity, with correlation coefficients (r≥0.991 5) for all of the analytes within the concentration range. The intra-day and inter-day precisions (RSD) were both less than 15%, and the accuracies (RE) ranged from -15% to 15%. The method had a good stability, and was suitable for the content determination of 8 constituents in rat bile. The extraction recoveries of the 8 analytes were more than 63.2%, and the RSD of IS-normalized matrix factors were no more than 15%, which met the requirements for analysis. According to the biliary excretion study, the bile excretion rates of the 8 analytes were relatively low, with great difference among the individuals. The results showed that the established method was simple, selective and specific, thus could be applied in the biliary excretion study of the 8 analytes in rat bile.

Effect of pyrolytic temperatures on the 2,4-dichlorophenol adsorption performance of biochar derived from Populus nigra.

To investigate the correlation between the physicochemical properties of biochar and its adsorption performance for 2,4-dichlorophenol (2,4-DCP), Populus nigra was subjected to oxygen-limited pyrolysis at temperatures ranging from 300 to 600 ℃. The experimental results showed that as the pyrolysis temperature increased, the specific surface area and degree of graphitization of the resultant biochar increased, but the amount of oxygen-containing functional groups decreased. Populus nigra biochar produced at 450 ℃ exhibits the best adsorption performance for 2,4-DCP due to its excellent physicochemical properties and greater electron exchange capability. The removal of 2,4-DCP is a multi-step adsorption process dominated by chemisorption, which involved oxygen-containing functional groups-mediated hydrogen bonding, as well as π-π electron donor-acceptor (EDA) interaction between the aromatic rings and Cl atoms. The study highlights the potential of Populus nigra residues for producing biochar as an affordable and effective adsorbent for 2,4-DCP removal.

Biochar from phytoremediation plant residues: a review of its characteristics and potential applications.

Phytoremediation is a cost-effective and eco-friendly plant-based approach promising technique to repair heavy metal-contaminated soils. However, a significant quantity of plant residues needs to be properly treated and utilized. Pyrolysis is an effective technology for converting residues to biochar, which can solve the problem and avoid secondary contamination. This paper reviews the generation, and physicochemical properties of biochar from phytoremediation residues, and its application in soil improvement, environmental remediation, and carbon sequestration. In spite of this, it is important to be aware of the potential toxicity of heavy metals in biochar and the environmental risks of biochar before applying it to practical applications. Future challenges in the production and application of residue-derived biochar include the rational selection of pyrolysis parameters and proper handling of potentially hazardous components in the biochar.

Structural characterization and screening of chemical markers of flavonoids in Lysimachiae Herba and Desmodii Styracifolii Herba by ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry based metabolomics approach.

In traditional Chinese medicine, Lysimachiae Herba (LH) and Desmodii Styracifolii Herba (DSH) have been widely used for the treatment of calculi, but there is a certain focus in clinical application. Flavonoids as their pharmacologically active substances were focusly studied to make clear of their chemical compositions and reveal the similarities and differences between LH and DHS by analysis of characteristic marker components at the molecular level. An ultra high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) approach based on metabolite profiling was established. The high-resolution data was acquired through data dependent acquisition (DDA) mode. Based on the targeted and untargeted analytical strategies, a total of 113 compounds were identified, of which 80 compounds existed in LH and 61 in DSH. Then multivariate statistical analysis was applied to further find the characteristic marker components, and a total number of 21 variables were screened as the valuable variables for discrimination. By matching with identified flavonoids, these 21 variables were corresponding to 15 flavonoids (including 6 from LH and 9 from DSH) which were firstly identified as the marker compounds. These results indicated that the UPLC-QTOF-MS/MS method with analysis strategy was a powerful tool for rapidly identification and screening of marker compounds of flavonoids between LH and DSH, and the 15 screened marker compounds provide a chemical basis for the further researches on the mechanisms of LH and DSH in the treatment of cholelithiasis and nephrolithiasis respectively.

Determination and Quantitative Comparison of Nucleosides in two Cordyceps by HPLC-ESI-MS-MS.

A hybrid quadruple linear ion trap liquid chromatography-tandem mass spectrometry (LC-MS-MS) analytical method has been developed for simultaneous determination of 13 nucleosides from Cordyceps cicadae and Cordyceps sinensis for assessing whether C. cicadae can become a substitute for C. sinensis, based on that C. cicadae has in common with C. sinensis for treating chronic diseases. Among the 13 compounds, three compounds including cytidine, hypoxanthine and 2'-deoxyguanosine were firstly identified and quantified in C. cicadae. Ideal separation was achieved in one single LC-MS-MS run of 12 min by optimized chromatographic conditions. The identification and quantification analysis of target compounds were performed in electrospray ionization tandem mass spectrometry. The limit of detection and quantity for 13 compounds were <42.0 and 84.2 ng/mL, respectively. The determination results of 12 batches of C. sinensis and 20 batches of C. cicadae were then analyzed and classified by multivariate statistical analysis. C. cicadae contained a relatively higher level of three nucleosides (cytidine, uracil and 2'-deoxyuridine) than those in C. sinensis. The results of this study provided the theoretical basis for the substitution of C. sinensis with C. cicadae. The optimized method could be used for the quality control and investigate bioactive compound variation of Cordyceps.