Although solid phase microextraction (SPME) has been used extensively for fingerprinting volatile compounds emitted by plants, there are very few such reports for direct insertion SPME. In this research, direct contact of SPME probes with the interstitial fluid of plants was investigated as a method for phytochemical analysis.
Objective
Medicinal plants from the Amazon have been the source of numerous drugs used in western medicine. However, a large number of species used in traditional medicine have not been characterized chemically, partly due to the difficulty of field work. In this project, the phytochemical composition of plants from several genera was fingerprinted by combining convenient field sampling by solid phase microextraction (SPME) with laboratory analysis by LC-MS. The new method was compared with classical sampling followed by liquid extraction (LE).
Methodology
SPME probes were prepared by coating stainless steel wires with a mixture of polyacrylonitrile and either RP-amide or HS-F5 silica particles. Sampling was performed by inserting the microextraction probes into various tissues of living plants in their natural environment. After in vivo extraction, the probes were sealed under vacuum and refrigerated until analyzed. The probes were desorbed in mobile phase and analyzed on a Waters Acquity UPLC with triple quadrupole mass spectrometer in positive ion mode.
Results
Twenty Amazonian plant species were sampled and unique metabolomic fingerprints were obtained. In addition, quantitative analysis was performed for previously identified compounds in three species. Comparison of the fingerprints obtained by in vivo SPME with those obtained by LE showed that 27% of the chromatographic features were unique to SPME, 57% were unique to LE, and 16% were common to both methods.
Conclusion
In vivo SPME caused minimal damage to the plants, was much faster than traditional liquid extraction, and provided unique fingerprints for all investigated plants. SPME revealed unique chromatographic features, undetected by traditional extraction, although it produced only half as many peaks as ethanol extraction. 相似文献
Free radicals cause alterations in cellular protein structure and function. Oxidized, nitrated, and chlorinated modifications of aromatic amino acids including phenylalanine and tyrosine are reliable biomarkers of oxidative stress and inflammation in clinical conditions.
Objective
To develop, validate and apply a rapid method for the quantification of known hallmarks of tyrosine oxidation, nitration and chlorination in plasma and tissue proteins providing a snapshot of the oxidative stress and inflammatory status of the organism and of target organs respectively.
Material and Methods
The extraction and clean up procedure entailed protein precipitation, followed by protein re-suspension and enzymatic digestion with pronase. An Ultra Performance Liquid Chromatography–tandem Mass Spectrometry (UPLC-MS/MS) method was developed to quantify protein released ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-nitrotyrosine (3NO2-Tyr) and 3-chlorotyrosine (3Cl-Tyr) as well as native phenylalanine (Phe) and tyrosine (p-Tyr) in plasma and tissue from a validated hypoxic newborn piglet experimental model.
Results
In plasma there was a significant increase in the 3NO2-Tyr/p-Tyr ratio. On the other hand m-Tyr/Phe and 3Cl-Tyr/p-Tyr ratios were significantly increased in liver of hypoxic compared with normoxic animals. Although no significant differences were found in brain tissue, a clear tendency to increased ratios was observed under hypoxic conditions.
Conclusions
UPLC-MS/MS has proven suitable for the analysis of plasma and tissue samples from newborn piglets. The analysis of biomarkers of protein oxidation, nitration and chlorination will be applied in future studies aiming to provide a deeper insight into the mechanisms of oxidation-derived protein modification caused during neonatal asphyxia and resuscitation. 相似文献
An epidemic of low‐quality medicines continues to endanger patients worldwide. Detection of such ‘medicines’ requires low cost, ambient ionization sources coupled to fieldable mass spectrometers for optimum sensitivity and specificity. With the use of triboelectric nanogenerators (TENGs), the charge required to produce gas‐phase ions for mass analysis can be obtained without the need for high‐voltage electrical circuitry, simplifying and lowering the cost of next‐generation mass spectrometry instruments.
Methods
A sliding freestanding (SF) TENG was coupled to a toothpick electrospray setup for the purposes of testing if falsified medicines could be fingerprinted by this approach. Extracts from both genuine and falsified medicines were deposited on the toothpick and the SF TENG actuated to generate electrical charges, resulting in gas‐phase ions for both active pharmaceutical ingredients and excipients.
Results
Our previous work had shown that direct analysis in real time (DART) ambient mass spectrometry can identify the components of multiple classes of falsified antimalarial medicines. Experiments performed in this study show that a simple extraction into methanol along with the use of a SF TENG‐powered toothpick electrospray can provide similar detection capabilities, but with much simpler and rugged instrumentation, and without the need for compressed gases or high‐voltage ion source power supplies.
Conclusions
TENG toothpick MS allows for rapid analyte ion detection in a safe and low‐cost manner, providing robust sampling and ionization capabilities. 相似文献
Exhaled breath condensate (EBC) is a biofluid collected non invasively that, enabling the measurement of several biomarkers, has proven useful in the study of airway inflammatory diseases, including asthma, COPD and cystic fibrosis. To the best of our knowledge, there is no previous report of any analytical method to detect ADMA in EBC.
Objectives
Aim of this work was to develop an online sample trapping and enrichment system, coupled with an UPLC–MS/MS method, for simultaneous quantification of seven metabolites related to “Arginine-ADMA cycle”, using the isotopic dilution.
Methods
Butylated EBC samples were trapped in an online cartridge, washed before and after each injection with cleanup solution to remove matrix components and switched inline into the high pressure analytical column. Multiple reaction monitoring in positive mode was used for analyte quantification by tandem mass spectrometry.
Results
Validation studies were performed in EBC to examine accuracy, precision and robustness of the method. For each compound, the calibration curves showed a coefficient of correlation (r2) greater than 0.992. Accuracy (%Bias) was <3% except for NMMA and H-Arg (<20%), intra- and inter-assay precision (expressed as CV%) were within ±20% and recovery ranged from 97.1 to 102.8% for all analytes.Inter-day variability analysis on 20 EBC of adult subjects did not demonstrate any significant variation of quantitative data for each metabolite. ADMA and SDMA mean concentrations (μmol L−1), measured in EBC samples of asthmatic adolescents are significantly increased (p < 0.0001) than in normal controls (0.0040 ± 0.0021 vs. 0.0012 ± 0.0005 and 0.0020 ± 0.0015 vs. 0.0002 ± 0.0001, respectively), as well the ADMA/Tyr (0.34 ± 0.09 vs. 0.12 ± 0.02, p < 0.0001) and the SDMA/Tyr ratio (0.10 ± 0.04 vs. 0.015 ± 0.004, p < 0.0001).
Conclusions
The proposed method features simple specimen preparation, maintenance of an excellent peak shape of all metabolites and reduced matrix effects as well mass spectrometer noise. Moreover, the possibility to perform different cycles of enrichment, using large injection volumes, compensated for the low concentration of analytes contained in EBC, leading to a good analytical sensitivity. Preliminary data obtained from asthmatic and healthy adolescents, demonstrated that the analytical method applied to EBC seems suitable not only for research purposes, but also for clinical routinely analysis. 相似文献
Diagnosis of pancreatic neuroendocrine tumours requires the study of patient plasma with multiple immunoassays, using multiple aliquots of plasma. The application of mass spectrometry based techniques could reduce the cost and amount of plasma required for diagnosis.
Methods
Plasma samples from two patients with pancreatic neuroendocrine tumours were extracted using an established acetonitrile‐based plasma peptide enrichment strategy. The circulating peptidome was characterised using nano and high flow rate liquid chromatography/mass spectrometry (LC/MS) analyses. To assess the diagnostic potential of the analytical approach, a large sample batch (68 plasmas) from control subjects, and aliquots from subjects harbouring two different types of pancreatic neuroendocrine tumour (insulinoma and glucagonoma), were analysed using a 10‐min LC/MS peptide screen.
Results
The untargeted plasma peptidomics approach identified peptides derived from the glucagon prohormone, chromogranin A, chromogranin B and other peptide hormones and proteins related to control of peptide secretion. The glucagon prohormone derived peptides that were detected were compared against putative peptides that were identified using multiple antibody pairs against glucagon peptides. Comparison of the plasma samples for relative levels of selected peptides showed clear separation between the glucagonoma and the insulinoma and control samples.
Conclusions
The combination of the organic solvent extraction methodology with high flow rate analysis could potentially be used to aid diagnosis and monitor treatment of patients with functioning pancreatic neuroendocrine tumours. However, significant validation will be required before this approach can be clinically applied. 相似文献
In this study,a novel numerical implementation for the adhesion of liquid droplets impacting normally on solid dry surfaces is presented. The advantage of this new approach, compared to the majority of existing models, is that the dynamic contact angle forming during the surface wetting process is not inserted as a boundary condition, but is derived implicitly by the induced fluid flow characteristics (interface shape) and the adhesion physics of the gas–liquid-surface interface (triple line), starting only from the advancing and receding equilibrium contact angles. These angles are required in order to define the wetting properties of liquid phases when interacting with a solid surface.
Methodology
The physical model is implemented as a source term in the momentum equation of a Navier-Stokes CFD flow solver as an “adhesion-like” force which acts at the triple-phase contact line as a result of capillary interactions between the liquid drop and the solid substrate. The numerical simulations capture the liquid–air interface movement by considering the volume of fluid (VOF) method and utilizing an automatic local grid refinement technique in order to increase the accuracy of the predictions at the area of interest, and simultaneously minimize numerical diffusion of the interface.
Results
The proposed model is validated against previously reported experimental data of normal impingement of water droplets on dry surfaces at room temperature. A wide range of impact velocities, i.e. Weber numbers from as low as 0.2 up to 117, both for hydrophilic (θadv = 10° – 70°) and hydrophobic (θadv = 105° – 120°) surfaces, has been examined. Predictions include in addition to droplet spreading dynamics, the estimation of the dynamic contact angle; the latter is found in reasonable agreement against available experimental measurements.
Conclusion
It is thus concluded that theimplementation of this model is an effective approach for overcoming the need of a pre-defined dynamic contact angle law, frequently adopted as an approximate boundary condition for such simulations. Clearly, this model is mostly influential during the spreading phase for the cases of low We number impacts (We < ˜80) since for high impact velocities, inertia dominates significantly over capillary forces in the initial phase of spreading. 相似文献
The new European Regulation on chemical safety, REACH, (Registration, Evaluation, Authorisation and Restriction of CHemical substances), is in the process of being implemented. Many chemicals used in industry require additional testing to comply with the REACH regulations. At the same time EU member states are attempting to reduce the number of animals used in experiments under the 3 Rs policy, (refining, reducing, and replacing the use of animals in laboratory procedures). Computational techniques such as QSAR have the potential to offer an alternative for generating REACH data. The FP6 project CAESAR was aimed at developing QSAR models for 5 key toxicological endpoints of which skin sensitisation was one.
Results
This paper reports the development of two global QSAR models using two different computational approaches, which contribute to the hybrid model freely available online.
Conclusions
The QSAR models for assessing skin sensitisation have been developed and tested under stringent quality criteria to fulfil the principles laid down by the OECD. The final models, accessible from CAESAR website, offer a robust and reliable method of assessing skin sensitisation for regulatory use.
Genome-wide aberrations of the classic epigenetic modification 5-methylcytosine (5mC), considered the hallmark of gene silencing, has been implicated to play a pivotal role in mediating carcinogenic transformation of healthy cells. Recently, three epigenetic marks derived from enzymatic oxidization of 5mC namely 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC), have been discovered in the mammalian genome. Growing evidence suggests that these novel bases possess unique regulatory functions and may play critical roles in carcinogenesis.
Methods
To provide a quantitative basis for these rare epigenetic marks, we have designed a biotin–avidin mediated enzyme-based immunoassay (EIA) and evaluated its performance in genomic DNA isolated from blood of patients diagnosed with metastatic forms of lung, pancreatic and bladder cancer, as well as healthy controls. The proposed EIA incorporates spatially optimized biotinylated antibody and a high degree of horseradish-peroxidase (HRP) labeled streptavidin, facilitating signal amplification and sensitive detection.
Results
We report that the percentages of 5mC, 5hmC and 5caC present in the genomic DNA of blood in healthy controls as 1.025 ± 0.081, 0.023 ± 0.006 and 0.001 ± 0.0002, respectively. We observed a significant (p < 0.05) decrease in the mean global percentage of 5hmC in blood of patients with malignant lung cancer (0.013 ± 0.003%) in comparison to healthy controls.
Conclusion
The precise biological roles of these epigenetic modifications in cancers are still unknown but in the past two years it has become evident that the global 5hmC content is drastically reduced in a variety of cancers. To the best of our knowledge, this is the first report of decreased 5hmC content in the blood of metastatic lung cancer patients and the clinical utility of this observation needs to be further validated in larger sample datasets. 相似文献
Precise analysis of four sulfur isotopes of sulfate in geological and environmental samples provides the means to extract unique information in wide geological contexts. Reduction of sulfate to sulfide is the first step to access such information. The conventional reduction method suffers from a cumbersome distillation system, long reaction time and large volume of the reducing solution. We present a new and simple method enabling the process of multiple samples at one time with a much reduced volume of reducing solution.
Methods
One mL of reducing solution made of HI and NaH2PO2 was added to a septum glass tube with dry sulfate. The tube was heated at 124°C and the produced H2S was purged with inert gas (He or N2) through gas‐washing tubes and then collected by NaOH solution. The collected H2S was converted into Ag2S by adding AgNO3 solution and the co‐precipitated Ag2O was removed by adding a few drops of concentrated HNO3.
Results
Within 2–3 h, a 100% yield was observed for samples with 0.2–2.5 μmol Na2SO4. The reduction rate was much slower for BaSO4 and a complete reduction was not observed. International sulfur reference materials, NBS‐127, SO‐5 and SO‐6, were processed with this method, and the measured against accepted δ34S values yielded a linear regression line which had a slope of 0.99 ± 0.01 and a R2 value of 0.998.
Conclusions
The new methodology is easy to handle and allows us to process multiple samples at a time. It has also demonstrated good reproducibility in terms of H2S yield and for further isotope analysis. It is thus a good alternative to the conventional manual method, especially when processing samples with limited amount of sulfate available. 相似文献
Phosphorus losses from agriculture pose an environmental threat to watercourses. A new approach using the stable oxygen isotope ratio of oxygen in phosphate (δ18OPO4 value) may help elucidate some phosphorus sources and cycling. Accurately determined and isotopically distinct source values are essential for this process. The δ18OPO4 values of animal wastes have, up to now, received little attention.
Methods
Phosphate (PO4) was extracted from cattle faeces using anion resins and the contribution of microbial PO4 was assessed. The δ18OPO4 value of the extracted PO4 was measured by precipitating silver phosphate and subsequent analysis on a thermal conversion elemental analyser at 1400°C, with the resultant carbon monoxide being mixed with a helium carrier gas passed through a gas chromatography (GC) column into a mass spectrometer. Faecal water oxygen isotope ratios (δ18OH2O values) were determined on a dual‐inlet mass spectrometer through a process of headspace carbon dioxide equilibration with water samples.
Results
Microbiological results indicated that much of the extracted PO4 was not derived directly from the gut fauna lysed during the extraction of PO4 from the faeces. Assuming that the faecal δ18OH2O values represented cattle body water, the predicted pyrophosphatase equilibrium δ18OPO4 (Eδ18OPO4) values ranged between +17.9 and +19.9‰, while using groundwater δ18OH2O values gave a range of +13.1 to +14.0‰. The faecal δ18OPO4 values ranged between +13.2 and +15.3‰.
Conclusions
The fresh faecal δ18OPO4 values were equivalent to those reported elsewhere for agricultural animal slurry. However, they were different from the Eδ18OPO4 value calculated from the faecal δ18OH2O value. Our results indicate that slurry PO4 is, in the main, derived from animal faeces although an explanation for the observed value range could not be determined. 相似文献
Previous studies have demonstrated that members of Trichoderma are able to generate appreciable amount of extracellular amylase and glucoamylase on soluble potato starch. In this study the α-amylase was purified and characterized from Trichoderma pseudokoningii grown on orange peel under solid state fermentation (SSF).
Results
Five α-amylases A1-A5 from Trichodrma pseudokoningii were separated on DEAE-Sepharose column. The homogeneity of α-amylase A4 was detected after chromatography on Sephacryl S-200. α-Amylase A4 had molecular weight of 30 kDa by Sephacryl S-200 and SDS-PAGE. The enzyme had a broad pH optimum ranged from 4.5 to 8.5. The optimum temperature of A4 was 50 °C with high retention of its activity from 30 to 80 °C. The thermal stability of A4 was detected up to 50 °C and the enzyme was highly stable till 80 °C after 1 h incubation. All substrate analogues tested had amylase activity toward A4 ranged from 12 to 100% of its initial activity. The Km and Vmax values of A4 were 4 mg starch/ml and 0.74 μmol reducing sugar, respectively. The most of metals tested caused moderate inhibitory effect, except of Ca2+ and Mg2+ enhanced the activity. Hg2+ and Cd+?2 strongly inhibited the activity of A4. EDTA as metal chelator caused strong inhibitory effect.
Conclusions
The properties of the purified α-amylase A4 from T. pseudokoningii meet the prerequisites needed for several applications.
Stilbene cleaving oxygenases (SCOs), also known as lignostilbene-α,β-dioxygenases (LSDs) mediate the oxidative cleavage of the olefinic double bonds of lignin-derived intermediate phenolic stilbenes, yielding small modified benzaldehyde compounds. SCOs represent one branch of the larger carotenoid cleavage oxygenases family. Here, we describe the structural and functional characterization of an SCO-like enzyme from the soil-born, bio-control agent Pseudomonas brassicacearum.
Methods
In vitro and in vivo assays relying on visual inspection, spectrophotometric quantification, as well as liquid-chormatographic and mass spectrometric characterization were applied for functional evaluation of the enzyme. X-ray crystallographic analyses and in silico modeling were applied for structural investigations.
Results
In vitro assays demonstrated preferential cleavage of resveratrol, while in vivo analyses detected putative cleavage of the straight chain carotenoid, lycopene. A high-resolution structure containing the seven-bladed β-propeller fold and conserved 4-His-Fe unit at the catalytic site, was obtained. Comparative structural alignments, as well as in silico modelling and docking, highlight potential molecular factors contributing to both the primary in vitro activity against resveratrol, as well as the putative subsidiary activities against carotenoids in vivo, for future validation.
Conclusions
The findings reported here provide validation of the SCO structure, and highlight enigmatic points with respect to the potential effect of the enzyme’s molecular environment on substrate specificities for future investigation.
Recent trends towards miniature and portable quadrupole mass spectrometry (QMS) entail challenges in instrumental sensitivity, which is influenced by 3D fringe field effects on ion transmission in the Quadrupole Mass Filter (QMF). The relationship of these effects with the gap from the ion source to the QMF entrance (source gap) is significant and little explored. We examine transmission characteristics experimentally and use the results to test the predictive accuracy of a recently developed 3D QMF simulation model. The model is then applied to directly investigate optimal transmission m/z ranges across multiple source gaps.
Methods
A portable single filter quadrupole mass spectrometer is used to analyse transmission characteristics across a range of common gases. We use an experimental approach originally proposed by Ehlert, enhanced with a novel method for absolute calibration of the transmission curve. Custom QMF simulation software employs the boundary element method (BEM) to compute accurate 3D electric fields. This is used to study the effects of the source gap on transmission efficiency.
Results
Experimental findings confirm a centrally peaked transmission curve; simulations correctly predict the optimal transmission location (in m/z) and percentage, and extend the experimental trend. We compare several methods for determining fringe field length, demonstrating how the size of the physical source gap influences both the length and the intensity of the fringe field at the QMF entrance. A complex relationship with ion transmission is revealed in which different source gaps promote optimal transmission at differing m/z ranges.
Conclusions
The presented results map the relationship between the source gap and transmission efficiency for the given instrument, using a simulation method transferrable to other setups. This is of importance to miniature and portable quadrupole mass spectrometers design for specific applications, for the first time enabling the source gap to be tailored for optimal transmission in the desired mass range. 相似文献
Patient-derived colorectal tumor organoids (CTOs) closely recapitulate the complex morphological, phenotypic, and genetic features observed in in vivo tumors. Therefore, evaluation of drug distribution and metabolism in this model system can provide valuable information to predict the clinical outcome of a therapeutic response in individual patients. In this report, we applied matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to examine the spatial distribution of the drug irinotecan and its metabolites in CTOs from two patients. Irinotecan is a prodrug and is often prescribed as part of therapeutic regimes for patients with advanced colorectal cancer. Irinotecan shows a time-dependent and concentration-dependent permeability and metabolism in the CTOs. More interestingly, the active metabolite SN-38 does not co-localize well with the parent drug irinotecan and the inactive metabolite SN-38G. The phenotypic effect of irinotecan metabolism was also confirmed by a viability study showing significantly reduced proliferation in the drug treated CTOs. MALDI-MSI can be used to investigate various pharmaceutical compounds in CTOs derived from different patients. By analyzing multiple CTOs from a patient, this method could be used to predict patient-specific drug responses and help to improve personalized dosing regimens.
Combretastatin A-4 (CA-4), which is an excellent antineoplastic agent, was isolated from Combretum caffrum. To date, structural modification studies of CA-4 have focused predominantly on the construction of new therapeutic agents for drug discovery. As a part of our ongoing work towards the modification of natural products, we have focused on the 3’-O-substituent groups in the B-ring of CA-4 under the hypothesis that these novel derivatives will possess good bioactivities and behave as effective antiproliferative pro-drugs.
Results
A series of novel CA-4 derivatives, which contained a 3’-O-substituted carbonic ether moiety, were synthesized and evaluated for their antitumor activities against four tumor cell lines, including MDA-MB-231, MCF-7, K562 and A549 cells. These derivatives exhibited clear antitumor activities, and CA-4E, in particular, showed the highest bioactivity of all of the derivatives tested against all four tumor cell lines, with IC50 values in the range of 1 to 180 nM. Based on its high bioactivity, CA-4E was subsequently selected to investigate the antitumor mechanism of these synthetic compounds. The cell cycle results demonstrated that CA-4E induced time- and dose-dependent G2/M arrest in a similar manner to CA-4, although its effect was more powerful than that of CA-4, and the apoptosis data showed that CA-4E induced cellular apoptosis in a dose-dependent manner.
Conclusions
The newly synthesized CA-4 derivatives exhibited good antitumor activities in vitro, with CA-4E, in particular, showing the highest bioactivity of all of the compounds tested. Furthermore, CA-4E induced time- and dose-dependent G2/M arrest and cellular apoptosis in a dose-dependent manner. Taken together, these results suggest that CA-4E should be subjected to further investigation as a potential anticancer drug candidate.
Tandem mass spectral library searching is finding increased use as an effective means of determining chemical identity in mass spectrometry-based omics studies. We previously reported on constructing a tandem mass spectral library that includes spectra for multiple precursor ions for each analyte. Here we report our method for expanding this library to include MS2 spectra of fragment ions generated during the ionization process (in-source fragment ions) as well as MS3 and MS4 spectra. These can assist the chemical identification process. A simple density-based clustering algorithm was used to cluster all significant precursor ions from MS1 scans for an analyte acquired during an infusion experiment. The MS2 spectra associated with these precursor ions were grouped into the same precursor clusters. Subsequently, a new top-down hierarchical divisive clustering algorithm was developed for clustering the spectra from fragmentation of ions in each precursor cluster, including the MS2 spectra of the original precursors and of the in-source fragments as well as the MSn spectra. This algorithm starts with all the spectra of one precursor in one cluster and then separates them into sub-clusters of similar spectra based on the fragment patterns. Herein, we describe the algorithms and spectral evaluation methods for extending the library. The new library features were demonstrated by searching the high resolution spectra of E. coli extracts against the extended library, allowing identification of compounds and their in-source fragment ions in a manner that was not possible before.
Blood–tissue partition coefficients indicate how a chemical will distribute throughout the body and are an important part of any pharmacokinetic study. They can be used to assess potential toxicological effects from exposure to chemicals and the efficacy of potential novel drugs designed to target certain organs or the central nervous system. In vivo measurement of blood–tissue partition coefficients is often complicated, time-consuming, and relatively expensive, so developing in vitro systems that approximate in vivo ones is desirable. We have determined such systems for tissues such as brain, muscle, liver, lung, kidney, heart, skin, and fat.
Results
Several good (p < 0.05) blood–tissue partition coefficient models were developed using a single water–solvent system. These include blood–brain, blood–lung, blood–heart, blood–fat, blood–skin, water–skin, and skin permeation. Many of these partition coefficients have multiple water–solvent systems that can be used as models. Several solvents—methylcyclohexane, 1,9-decadiene, and 2,2,2-trifluoroethanol—were common to multiple models and thus a single measurement can be used to estimate multiple blood–tissue partition coefficients. A few blood–tissue systems require a combination of two water–solvent partition coefficient measurements to model well (p < 0.01), namely: blood–muscle: chloroform and dibutyl ether, blood–liver: N-methyl-2-piperidone and ethanol/water (60:40) volume, and blood–kidney: DMSO and ethanol/water (20:80) volume.
Conclusion
In vivo blood–tissue partition coefficients can be easily estimated through water–solvent partition coefficient measurements.
Considerable efforts are being extended to develop more effective methods to detect drugs in forensic science for applications such as preventing doping in sport. The aim of this study was to develop a sensitive and accurate method for analytes of forensic and toxicological nature in human hair at sub-pg levels.
Results
The hair test covers a range of different classes of drugs and metabolites of forensic and toxicological nature including selected anabolic steroids, cocaine, amphetamines, cannabinoids, opiates, bronchodilators, phencyclidine and ketamine. For extraction purposes, the hair samples were decontaminated using dichloromethane, ground and treated with 1 M sodium hydroxide and neutralised with hydrochloric acid and phosphate buffer and the homogenate was later extracted with hexane using liquid-liquid extraction (LLE). Following extraction from hair samples, drug-screening employed liquid chromatography coupled to tandem mass spectrometric (LC-MS/MS) analysis using dynamic multiple reaction monitoring (DYN-MRM) method using proprietary software. The screening method (for?>?200 drugs/metabolites) was calibrated with a tailored drug mixture and was validated for 20 selected drugs for this study. Using standard additions to hair sample extracts, validation was in line with FDA guidance. A Zorbax Eclipse plus C18 (2.1 mm internal diameter × 100 mm length × 1.8 μm particle size) column was used for analysis. Total instrument run time was 8 minutes with no noted matrix interferences. The LOD of compounds ranged between 0.05-0.5 pg/mg of hair. 233 human hair samples were screened using this new method and samples were confirmed positive for 20 different drugs, mainly steroids and drugs of abuse.
Conclusions
This is the first report of the application of this proprietary system to investigate the presence of drugs in human hair samples. The method is selective, sensitive and robust for the screening and confirmation of multiple drugs in a single analysis and has potential as a very useful tool for the analysis of large array of controlled substances and drugs of abuse.
The plant Alisma plantago-aquatica Linnaeus, which is widely distributed in southwest of China, is the main material of traditional Chinese medicine “Zexie”. It was used as folk medicine for immune-modulation, anti-tumor, anti-inflammatory and antibacterial. Previous chemical studies on A. plantago-aquatica reported the identification of triterpenes, diterpenes, sesquiterpenes, steroids, alkaloids and phenolic acid. Terpenes and phenolic acid were regard as major secondary metabolites from this medicine plant.
Results
A new phenolic acid, plantain A (1), along with four known compounds (2–5) were isolated and identified from A. plantago-aquatica by extensive chromatographic and spectrometric methods. In the present study, the levels of TNF-α, IL-1β, COX-2, PEG2 and TGF-β1 were increased in model group rats, whereas on treatment with the isolated compound (1 and 4) at 50 mg/kg, there was a significant decrease in the cytokine levels. Therefore, the anti-CNP effect of 1 and 4 may be related to their anti-inflammatory properties.
Conclusions
A new phenolic acid and four known phenolic compounds were isolated from A. plantago-aquatica. Moreover, compounds 1 and 4 shows significant anti-chronic prostatitis activity in rats.
