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Chemistry, An Asian Journal Oct 2021An efficient synthetic method for structurally various isochromenoindolones has been demonstrated through Rh(III)-catalyzed C-H activation followed by a cyclization...
An efficient synthetic method for structurally various isochromenoindolones has been demonstrated through Rh(III)-catalyzed C-H activation followed by a cyclization reaction of N-methoxyarylamides with 3-diazooxindoles. The sequential reaction involves the streamlined formation of C-C and C-O bonds in one pot. The present method provides a broad range of isochromenoindolones as a new privileged scaffold in moderate to good yields with the release of methoxyamine and molecular nitrogen and has the benefits of a broad substrate scope and good functional group tolerance.
PubMed: 34387948
DOI: 10.1002/asia.202100797 -
Steroids Nov 2020Anabolic hormones, which cause muscle growth, have been banned for anabolic purposes in animal husbandry in Europe since the 1980s. Control of hormones from the list of...
Anabolic hormones, which cause muscle growth, have been banned for anabolic purposes in animal husbandry in Europe since the 1980s. Control of hormones from the list of Annex I to Directive 96/23/EC is mandatory in the European Union. The presence of hormones in samples of animal origin may be due to their endogeneous nature or illegal use. One way to distinguish their origin is to study hormones, particularly steroids in the form of ester derivatives. In the body synthetic hormone esters could be only exogenous therefore their detection in animal tissues is the undisputed evidence of illegal administration. The analytical procedure involves the extraction of esters from serum with organic solvents, derivatisation with methoxyamine and detection by liquid chromatography tandem mass spectrometry. The method was approved in accordance with the applicable legislative criteria and its effectiveness was verified in the proficiency test. The research material consisted of bovine serum samples officially taken. During the validation good apparent recovery, precision, decision limits and detection capabilities in the range 0.006-0.012 µg L and 0.010-0.020 µg L respectively were obtained. The developed method met the criteria for confirmation set out in Commission Decision 2002/657/EC. Since the inclusion of serum in 2018 for testing for testosterone esters in the National Residue Control Program, 130 samples have been examined. In none of the serum samples, esters above the decision limits were found. The control of animals and food of animal origin for hormone esters will be continued to ensure the health and safety of consumers.
Topics: Animals; Blood Chemical Analysis; Cattle; Chromatography, Liquid; Esters; Tandem Mass Spectrometry; Testosterone
PubMed: 32882255
DOI: 10.1016/j.steroids.2020.108723 -
RSC Advances Oct 2019Sapitinib (AZD8931, SAP) is an epidermal growth factor receptor (EGFR) family (pan-erbB) tyrosine kinase inhibitor. In multiple tumor cell lines, SAP has been shown to...
Sapitinib (AZD8931, SAP) is an epidermal growth factor receptor (EGFR) family (pan-erbB) tyrosine kinase inhibitor. In multiple tumor cell lines, SAP has been shown to be a much more potent inhibitor of EGF-driven cellular proliferation than gefitinib. In this metabolic study, we tested the generation of reactive intermediates from SAP using human liver microsomes and a capturing agent (potassium cyanide) to trap the iminium reactive intermediates. The same metabolic reaction was further repeated in the presence of methoxyamine to trap aldehyde intermediates. The identification of SAP metabolites revealed that the hydroxylation metabolic reaction represents the major metabolic pathway occurring at the piperidine moiety. We characterized six phase I metabolites in addition to three reactive intermediates (, two iminiums and one aldehyde), therefore suggesting two probable SAP-bioactivation pathways. We hypothesized that the piperidine ring nitrogen (cyclic tertiary amine) activated the two adjacent α-carbons within the ring. The oxidative dealkylation of the -acetamide group led to an unstable aldehyde that was trapped using methoxyamine, generating an oxime adduct that was detected using liquid chromatography-tandem mass spectrometry (LC-MS/MS). To the best of our knowledge, this is the first study presenting the structural characterization of SAP reactive intermediates.
PubMed: 35529145
DOI: 10.1039/c9ra03926k -
Drug Testing and Analysis Oct 2019Psychoactive substances of the 2C-series are phenethylamine-based designer drugs that can induce psychostimulant and hallucinogenic effects. The so-called 2C-FLY series...
Phenethylamine-derived new psychoactive substances 2C-E-FLY, 2C-EF-FLY, and 2C-T-7-FLY: Investigations on their metabolic fate including isoenzyme activities and their toxicological detectability in urine screenings.
Psychoactive substances of the 2C-series are phenethylamine-based designer drugs that can induce psychostimulant and hallucinogenic effects. The so-called 2C-FLY series contains rigidified methoxy groups integrated in a 2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran core. The aim of the presented work was to investigate the in vivo and in vitro metabolic fate including isoenzyme activities and toxicological detectability of the three new psychoactive substances (NPS) 2C-E-FLY, 2C-EF-FLY, and 2C-T-7-FLY to allow clinical and forensic toxicologists the identification of these novel compounds. Rat urine, after oral administration, and pooled human liver S9 fraction (pS9) incubations were analyzed by liquid chromatography-high-resolution tandem mass spectrometry (LC-HRMS/MS). By performing activity screenings, the human isoenzymes involved were identified and toxicological detectability in rat urine investigated using standard urine screening approaches (SUSAs) based on gas chromatography (GC)-MS, LC-MS , and LC-HRMS/MS. In total, 32 metabolites were tentatively identified. Main metabolic steps consisted of hydroxylation and N-acetylation. Phase I metabolic reactions were catalyzed by CYP2D6, 3A4, and FMO3 and N-acetylation by NAT1 and NAT2. Methoxyamine was used as a trapping agent for detection of the deaminated metabolite formed by MAO-A and B. Interindividual differences in the metabolism of the 2C-FLY drugs could be caused by polymorphisms of enzymes involved or drug-drug interactions. All three SUSAs were shown to be suitable to detect an intake of these NPS but common metabolites of 2C-E-FLY and 2C-EF-FLY have to be considered during interpretation of analytical findings.
Topics: Animals; Chromatography, Liquid; Designer Drugs; Humans; Male; Microsomes, Liver; Phenethylamines; Psychotropic Drugs; Rats, Wistar; Substance Abuse Detection; Tandem Mass Spectrometry
PubMed: 31299701
DOI: 10.1002/dta.2675 -
Organic & Biomolecular Chemistry Jun 2021We developed a novel Pd-catalysed enantioselective synthesis of C-N bonds using the chiral scaffold of DNA. The non-covalently linked [Pd(phen)(OAc)2] with st-DNA...
We developed a novel Pd-catalysed enantioselective synthesis of C-N bonds using the chiral scaffold of DNA. The non-covalently linked [Pd(phen)(OAc)2] with st-DNA catalysed the Markonicov hydroamination of β-nitrostyrene with methoxyamine for the first time with >75% enantiomeric excess (ee) in an aqueous buffer (pH 7.4) at room temperature.
PubMed: 34028485
DOI: 10.1039/d1ob00714a -
Journal of Agricultural and Food... Oct 2020Serum analysis has received much attention in regulatory analysis of food-producing animals, especially for anabolic steroids. The possibility of confirming the parent...
Serum analysis has received much attention in regulatory analysis of food-producing animals, especially for anabolic steroids. The possibility of confirming the parent drugs with minimum metabolization enables the detection of intact steroid esters, whose identification represents unequivocal proof of drug administration. This work involved the development and validation of a quantitative LC-MS/MS method to determine 30 steroids and steroid esters in bovine serum. Sensitivity was improved using microwave-assisted chemical derivatization with methoxyamine hydrochloride. The validation was successfully conducted in accordance with the Decision 657/2002/EC guidelines. An in vivo experiment was performed on 12 crossbred steers in which two commercial formulations containing boldenone undecylenate and testosterone propionate were administrated via intramuscular injections. The samples were collected over a period of 120 days, in which both intact esters were identified within 11 days postadministration. 17β-Boldenone was observed after 92 days for 2 steers and 56 days for the other animals. The applicability of a cut-off level to the ratio between 17β-testosterone and epitestosterone was evaluated in an attempt to differentiate testosterone abuse from endogenous production. It could be observed that a calculated ratio above this level is strong evidence of drug administration, although a high false-negative rate was obtained.
Topics: Anabolic Agents; Animals; Cattle; Chromatography, High Pressure Liquid; Drug Residues; Male; Tandem Mass Spectrometry; Testosterone; Testosterone Propionate
PubMed: 32960588
DOI: 10.1021/acs.jafc.0c03621 -
Wei Sheng Yan Jiu = Journal of Hygiene... May 2020To establish a gas chromatography-mass spectrometry(GC-MS) method for determination of seven sugars and sugar alcohols in infants Ying Yang Bao nutritional supplements.
OBJECTIVE
To establish a gas chromatography-mass spectrometry(GC-MS) method for determination of seven sugars and sugar alcohols in infants Ying Yang Bao nutritional supplements.
METHODS
The samples were extracted with pure water and diluted with 95% ethanol. After being dried by nitrogen, methoxyamine hydrochloride oxime was dissolved in pyridine and derivatized by MSTFA. The capillary column TG-5 Ms(30 m×0. 25 mm, 0. 25 μm) was used for determination by GC-MS.
RESULTS
The limits of detection(LODs)were 1. 0-3. 0 mg/g and the limits of quantification(LOQs)were 3. 3-10. 0 mg/g. The average recoveries of seven kinds of sugar and sugar alcohols were 86. 7%-96. 7%, and the relative standard deviation was less than 5. 1%(n=6). The contents of seven sugars and sugar alcohols in soybean matrix nutritional supplements were determined in the range of 0. 25-13. 70 g/100 g, which was consistent with the nutrition label of the products.
CONCLUSION
The method is convenient, mild and fit for batch sample analysis.
Topics: Gas Chromatography-Mass Spectrometry; Limit of Detection; Sugar Alcohols; Sugars
PubMed: 32693894
DOI: No ID Found -
Clinical Chemistry Sep 2020For high-volume assays, optimizing throughput reduces test cost and turn-around time. One approach for liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays...
BACKGROUND
For high-volume assays, optimizing throughput reduces test cost and turn-around time. One approach for liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays is sample multiplexing, wherein the analyte of interest is derivatized in different specimens with reagents of different molecular weight (differential mass tagging). Specimens can then be combined and simultaneously analyzed within a single injection to improve throughput. Here we developed and validated a quantitative, sample-multiplexed LC-MS/MS assay for serum total testosterone (TT) based on this approach.
METHODS
For the sample-multiplexed assay, calibrators, controls, and patient specimens were first extracted separately. After mass tagging with either methoxyamine or hydroxylamine, they were combined and injected into the LC-MS/MS system. To evaluate assay performance, we determined limit of quantification (LOQ), linearity, recovery, and imprecision. A method-comparison study was also performed, comparing the new assay with the standard LC-MS/MS assay in 1574 patient specimens.
RESULTS
The method was linear from 2.5 to 2000 ng/dL, with accuracies from 93% to 104% for both derivatives. An LOQ of 1.0 ng/dL was achieved. Intra-assay and total CVs across 4 quality control concentrations were less than 10%. The assay demonstrated good agreement (Deming regression, 1.03x + 6.07) with the standard LC-MS/MS assay for the patient specimens tested (TT, 3 to 4862 ng/dL).
CONCLUSION
Sample multiplexing by differential mass tagging of TT increases LC-MS/MS throughput 2-fold without compromising analytical accuracy and sensitivity.
Topics: Chromatography, Liquid; Humans; Tandem Mass Spectrometry; Testosterone
PubMed: 32870993
DOI: 10.1093/clinchem/hvaa117 -
Free Radical Biology & Medicine Feb 2021It is well known that lipid carbon radicals (lipid radicals) are the origin of lipid peroxidation and are involved in various diseases such as cancer. Therefore, the in...
It is well known that lipid carbon radicals (lipid radicals) are the origin of lipid peroxidation and are involved in various diseases such as cancer. Therefore, the in vivo detection of lipid radicals would be expected to lead to early diagnosis of these diseases. However, there are no methods for measuring lipid radicals in vivo. Nitroxides are known to be highly reactive with lipid radicals, but they tend to be reduced in vivo. Focusing on the excellent detection sensitivity of nuclear medical imaging, we have developed a radioiodinated nitroxide derivative with resistance to bioreduction for the in vivo detection of lipid radicals. The desired compound was obtained successfully and was highly stable against bioreduction while maintaining high reactivity toward lipid radicals. The I-125 labeling was efficacious with radiochemical yields of 84-87% and radiochemical purities of >99%. A cellular uptake assay showed that the radioiodinated compound was significantly taken up by cells under lipid radical-producing conditions compared to that in the absence of lipid radical production. A biodistribution study indicated that the radioiodinated compound accumulated more in organs where lipid peroxidation was promoted than the methoxyamine derivative, which lost reactivity to lipid radicals. These results indicated that the developed probe became trapped in cells or organs by reacting with lipid radicals. Thus, the radioiodinated nitroxide is a candidate probe for in vivo detection of lipid radicals.
Topics: Antioxidants; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Free Radicals; Iodine Radioisotopes; Lipids; Nitrogen Oxides; Tissue Distribution
PubMed: 33359688
DOI: 10.1016/j.freeradbiomed.2020.12.028 -
Journal of Fungi (Basel, Switzerland) Feb 2021Pathogenic microbes are exposed to a number of potential DNA-damaging stimuli during interaction with the host immune system. Microbial survival in this situation...
Pathogenic microbes are exposed to a number of potential DNA-damaging stimuli during interaction with the host immune system. Microbial survival in this situation depends on a fine balance between the maintenance of DNA integrity and the adaptability provided by mutations. In this study, we investigated the association of the DNA repair response with the virulence of , a basidiomycete that causes life-threatening meningoencephalitis in immunocompromised individuals. We focused on the characterization of and putative genes, aiming to evaluate a possible role of the predicted Apurinic/apyrimidinic (AP) endonucleases 1 and 2 of the base excision repair (BER) pathway on response to stress conditions and virulence. Our results demonstrated the involvement of the putative AP-endonucleases Apn1 and Apn2 in the cellular response to DNA damage induced by alkylation and by UV radiation, in melanin production, in tolerance to drugs and in virulence of in vivo. We also pointed out the potential use of DNA repair inhibitor methoxy-amine in combination with conventional antifungal drugs, for the development of new therapeutic approaches against this human fungal pathogen. This work provides new information about the DNA damage response of the highly important pathogenic fungus .
PubMed: 33673204
DOI: 10.3390/jof7020133