Simultaneous screening of 239 synthetic cannabinoids and metabolites in blood and urine samples using liquid chromatography-high resolution mass spectrometry.

Synthetic cannabinoids (SCs) are new psychoactive substances that function as endocannabinoid CB1 and CB2 receptor agonists. Abuse of SCs can lead to symptoms such as confusion, dizziness, and even death. At present, Synthetic cannabinoids constitute one of the largest groups of new psychoactive substances and become popular recreational drugs of abuse for their psychoactive properties. The continuous transformation of SCs also leads to an endless emergence of new types. An efficient, high-throughput screening method is therefore very important for their identification. This paper describes a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for simultaneously screening 179 SCs and 80 SC metabolites in blood and urine. Simple acetonitrile was used to precipitate the blood and urine proteins, and the supernatants obtained after centrifugation were analyzed. The LC-HRMS run time was 20 min. The mass spectrometer used an ESI source with a scanning range of m/z 100-1000. LC-HRMS provided accurate mass, retention time, and fragment ions for qualitative analysis. The method validation results showed that the limits of detection (LODs) for over 80% compounds were 5 ng/mL in blood and urine samples. At low concentrations (50 ng/mL), 229 compounds (95.8%) in the blood showed recoveries of more than 50%, and 232 compounds (97.1%) had matrix effects greater than 80%. In the urine, 219 compounds (91.6%) had recoveries above 50%, and the matrix effects of 234 compounds (97.9%) were greater than 80%. This method was successfully applied to actual forensic cases.

Suspect screening and untargeted analysis of veterinary drugs in food by LC-HRMS: Application of background exclusion-dependent acquisition for retrospective analysis of unknown xenobiotics.

The presence of veterinary drug and pesticide residues in food products pose considerable threats to human health. Monitoring of these residues in food is mainly carried out using targeted analysis by triple quadrupole mass spectrometry. However, these methods are not suitable for suspect screening and untargeted analysis of unknowns. The main objectives of this study were to develop a new high-resolution mass spectrometry (HRMS)-based analytical strategy for retrospective analysis of suspect and unknown xenobiotics and to evaluate its performance in the tentative identification of 48 veterinary drugs as "unknowns" spiked in a pork sample. In the analysis, a newly developed background exclusion data-dependent acquisition (BE-DDA) technique was employed to trigger the product ion (MS/MS) spectral acquisition of the "unknowns", and an in-house precise-and-thorough background-subtraction (PATBS) technique was applied to detect these "unknowns". Results showed that untargeted data mining of the acquired LC-MS dataset by PATBS was able to find all the 48 veterinary drugs and 46 of them were triggered by BE-DDA to generate accurate MS/MS spectra. The dataset of recorded accurate full-scan mass and MS/MS spectra of all the xenobiotics of the test pork sample is defined as the xenobiotics profile. Searching the xenobiotic profile of the test pork sample using mass spectral data of selected veterinary drugs (as suspects) from the mzCloud spectral library led to the correct hits. Searching against the mzCloud spectral library using the mass spectral data of selected individual veterinary drugs (as unknowns) from the xenobiotics profile tentatively confirmed their identities. In contrast, analysis of the same sample using ion intensity-data dependent acquisition only recorded the MS/MS spectra for 34 veterinary drugs. In addition, a data independent acquisition method enabled the acquisition of the fragment spectra for 44 veterinary drugs, but their spectral data displayed only one or a few true product ions of individual analytes of interest along with many fragments from coeluted biological components and background noises. This study demonstrates that this analytical strategy has a potential to become a practical tool for the retrospective suspect screening and untargeted analysis of unknown xenobiotics in a biological sample such as veterinary drugs and pesticides in food products.

Artificial intelligence and network pharmacology based investigation of pharmacological mechanism and substance basis of Xiaokewan in treating diabetes.

Xiaokewan is a typical Traditional Chinese medicine (TCM) for diabetes and contains various natural chemicals, such as lignans, flavonoids, saponins, polysaccharides, and western medicine glibenclamide. In the current study, a highly efficient system for screening hypoglycemic efficacy constituents of Xiaokewan has been developed with the integration of intelligent data acquisition, data mining, network pharmacology, and computer assisted target fishing. With the combination of background exclusion data dependent acquisition (BE-DDA) and non-targeted precise-and-thorough background-subtraction (PATBS) techniques, a novel workflow has been established for the non-targeted recognition and identification of TCM constituents in vivo, and has been applied to the exposure study of Xiaokewan in rat. In this case, an interesting correlation among drug, target, and disease can be established, by combining the screening or characterization results with the strategy of network pharmacology and multiple computer assisted techniques. Consequently, five main constituents (puerarin, daidzein, formononetin, deoxyschizandrin and glibenclamide) exposed in vivo have been selected as effective hypoglycemic components. Meanwhile, the network pharmacology experimental results showed that these five constituents could act on various drug targets, such as PI3K, PTP1B, MAPK, AKT, TNF, and NF-κB. These five constituents might be involved in the regulation of ß-cell function or exhibit inflammation inhibition ability to relieve the pathophysiological process of disease from multiple links. Furthermore, the pharmacological effects of these five constituents have been verified by diabetic zebrafish model. The zebrafish model results showed that the TCM monomer mixture without glibenclamide exhibited similar hypoglycemic activity with Xiaokewan. Although the monomer mixture with glibenclamide showed better activity than Xiaokewan only, the deoxyschizandrin (TCM constituent of Xiaokewan) exhibited best hypoglycemic performance. In summary, the above results indicated that the application of both intelligent recognition technology in mass spectrometry dataset and computerized network pharmacology might provide a pioneering approach for investigating the substance basis of TCM and searching lead compounds from natural sources.

High-throughput screening of triplex DNA binders from complicated samples by 96-well pate format in conjunction with peak area-fading UHPLC-Orbitrap MS.

Conventional strategies for the screening of DNA triplex binders cannot be used for complicated samples, such as ligand libraries created by combinatorial chemistry or from natural product extracts. In the current study, an ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometry (UHPLC-Orbitrap-MS)-based approach, which we call peak area-fading (PAF) UHPLC-Orbitrap-MS and was designed for just such a purpose, is reported. The triplex DNA modified 96-well plate and the single stranded oligonucleotide modified 96-well plate (as control) were incubated with ligand libraries, and the unbound ligands were directly determined via UHPLC-ESI-MS. The binders were detected through the decrease (fading) in the peak areas compared to those of the control group. Several factors, such as incubation time, incubation temperature, and buffer, which might affect the binding affinity and reproducibility, were optimized. The potential of the approach was examined using the extracts of Rhizoma Coptidis and Phellodendron chinense Schneid cortexe. The triplex DNA-binding capabilities of the five components (epiberberine, coptisine, jatrorrhizine, berberrubine, and columbamine) were found for the first time, indicating their efficiency for the analysis of complicated samples. In contrast to our previous study, which suffered from a serious drawback of poor reproducibility, this method is more robust and more suitable for high-throughput measurements, opening a new experimental strategy in assessing large libraries of potential drug candidates that work by forming a drug/DNA complex.

Pharmacokinetics, bioavailability, and metabolism of Notoginsenoside Fc in rats by liquid chromatography/electrospray ionization tandem mass spectrometry.

Notoginsenoside Fc (NGFc) is a protopanaxadiol-type (PPD-type) saponin from Panax notoginseng, which has perfect anti-platelet aggregatory effect. However, its pharmacokinetics and metabolism in vivo remain unknown. In this study, a simple and sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC-MS/MS) method was first developed for the determination of NGFc in rat plasma. After methanol-mediated protein precipitation, separation was achieved on a C18 column with MS detection operated in negative SRM mode at m/z 604.56→m/z 783.90 and m/z 799.93→m/z 637.64 for NGFc and IS, respectively. The assay was linear over the concentration range (r>0.995) with the LLOQ of 0.002µg/ml. The intra- and inter-day precisions (R.S.D.) were 2.45-12.36% and 3.67-14.22%, respectively; whereas accuracy ranged from (R.R.) 93.90% to 99.41%. The extraction recovery, stability, and matrix effect were within the acceptable limits. The validated LC-MS/MS method was successfully applied to the pre-clinical pharmacokinetic studies of NGFc in rat. After oral and intravenous administration, NGFc showed dose-independent pharmacokinetic behaviors with a t1/2 of >22h and its oral bioavailability was 0.10-0.14%. In addition, a total of 10 metabolites were detected and structurally characterized by UPLC-Q/TOF-MS technique, which suggested that deglycosylation was the major metabolic pathway for NGFc in rats.

[Determination of six progesterones in milk by on-line cleanup liquid chromatography-tandem mass spectrometry].

A new method using TurboFlow on-line cleanup liquid chromatography combined with tandem mass spectrometry (MS/MS) has been developed for simultaneous determination of six progesterones including 19-norethindrone, 17alpha-hydroxyprogesterone, medroxyprogesterone, megestrol acetate, progesterone and melengestrol acetate in milk. Samples were extracted by acetonitrile. The analytes in extract were on-line purified directly on Cyclone-P purification column where the sample matrices were washed away. Subsequently, the analytes which were eluted from the extraction column onto Phenyl-Hexyl column were separated with a gradient elution, and detected with electrospray ionization mass spectrometry in the positive scan mode using multiple reaction monitoring (MRM). The isotope internal standards were employed for quantification. As a result, the linearities were satisfactory with the correlation coefficients of > 0.999 at concentrations ranging from 0.1 microg/L to 50 microg/L. Based on the repeated analysis of a known blank sample, the limit of quantification (LOQ) is 0.5 microg/kg. Average recoveries of the analytes fortified at three levels (1, 5 and 25 microg/kg) ranged from 90.8% to 107.5%, and the relative standard deviations (RSDs) ranged from 6.3% to 11.8%. This proposed method is simple, rapid, sensitive and highly selective, and can be applied to simultaneous identification an quantification of the six progesterones in milk.

Evaluation of alkaloids binding to the parallel quadruplex structure [d(TGGGGT)]4 by electrospray ionization mass spectrometry.

In this study, electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding interaction of six alkaloids with parallel intermolecular G-quadruplex [d(TGGGGT)](4), and five alkaloids including berberine, jatrorrhizine, palmatine, tetrandrine, and fangchinoline showed complexation with the target DNA. Relative binding affinities were estimated on the basis of mass spectrometric data. The slight differences in chemical structures of berberine, jatrorrhizine, and palmatine had little influence on their binding affinities to [d(TGGGGT)](4). Tetrandrine and fangchinoline selectively bound to [d(TGGGGT)](4) versus duplex DNA. Collision-induced dissociation (CID) experiments showed that the complexes with berberine, jatrorrhizine, and palmatine dissociated via strand separation and ligand retaining in the strand while the complexes with tetrandrine and fangchinoline were dissociated via ligand elimination. A comparison of dissociation patterns in CID experiments of complexes with the alkaloids to those with the traditional G-quadruplex DNA binders suggested an end-stacking binding mode for tetrandrine and fangchinoline and an intercalation binding mode for berberine, jatrorrhizine, and palmatine to the target DNA. The current work not only provides deep insight into alkaloid/[d(TGGGGT)](4) complexes and useful guidelines for design of efficient anticancer agents but also demonstrates the utility of ESI-MS as a powerful tool for evaluating interaction between ligand and quadruplex DNA.

High-performance liquid chromatography-electrospray ionization-mass spectrometry ligand fishing assay: a method for screening triplex DNA binders from natural plant extracts.

A novel ligand fishing assay was established to screen triplex DNA binders from complicated samples by a combination of immobilization of triplex DNA on agarose beads and high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). The biotinylated oligodeoxynucleotides were first bound to the streptavidin agarose beads and then incubated with the duplex DNA as the baits for ligand fishing. This assay was validated by the testing ligand library consisting of coralyne, ethidium bromide, vitexin, and formononetin. The binding affinities of ligands to target DNA were also obtained based on the calibration curves of ligands. Two components (berberine and palmatine) in the extract of Phellodendron chinense Schneid cortexes were fished out as triplex DNA binders by this assay, which indicated its feasibility for screening triplex DNA binders from complicated samples. This preliminary assay can be used for not only screening binders of triplex DNA from natural products extracts but also can obtain their binding affinity information.