Liquid Chromatography Quadrupole Time-of-flight Mass Spectrometry Research Articles

Application of a simultaneous screening method for the detection of new psychoactive substances in various matrix samples using liquid chromatography/electrospray ionization tandem mass spectrometry and liquid chromatography/quadrupole time‐of‐flight mass spectrometry

Recently, new psychoactive substances (NPS) emerged as a public health risk. Particularly, their chemical structures are modified to avoid detection. Synthetic NPS with effects similar to those of illegal drugs have been recently detected and synthesised worldwide, including MDMB-FUBINACA and APINAC, making it essential to rapidly and accurately detect NPS. Fourteen NPS with similar structures were selected and their structures identified using 1 H and 13 C NMR spectroscopy. Additionally, we proposed the fragmentation pattern of each compound using LC-QTOF-MS. A simultaneous analytical method using ESI-LC-MS/MS was also developed and applied to real samples to detect 14 NPS. The method was validated based on the specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, matrix effect, and stability according to international validation guidelines. The established method was used to screen 65 different matrix samples using LC-ESI-MS/MS. By comparing the calculated product ion ratios with those of standards, 2C-B in one real samples and 5F-MDMB-PICA in 20 samples were identified. For re-confirmation of detected compounds, each fragmentation pattern of each compound was compared to that of each standard using LC-QTOF-MS. In this study, LC-QTOF-MS were used to elucidate the structures and fragmentation patterns of 14 NPS. A simultaneous method was developed using LC-ESI-MS/MS, which was applied to 65 real samples. The presented method and results can assist in ensuring the safety of public health from illegal adulteration.

Analyses of Lipid A Diversity in Gram-Negative Intestinal Bacteria Using Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry.

Lipid A is a characteristic molecule of Gram-negative bacteria that elicits an immune response in mammalian cells. The presence of structurally diverse lipid A types in the human gut bacteria has been suggested before, and this appears associated with the immune response. However, lipid A structures and their quantitative heterogeneity have not been well characterized. In this study, a method of analysis for lipid A using liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) was developed and applied to the analyses of Escherichia coli and Bacteroidetes strains. In general, phosphate compounds adsorb on stainless-steel piping and cause peak tailing, but the use of an ammonia-containing alkaline solvent produced sharp lipid A peaks with high sensitivity. The method was applied to E. coli strains, and revealed the accumulation of lipid A with abnormal acyl side chains in knockout strains as well as known diphosphoryl hexa-acylated lipid A in a wild-type strain. The analysis of nine representative strains of Bacteroidetes showed the presence of monophosphoryl penta-acylated lipid A characterized by a highly heterogeneous main acyl chain length. Comparison of the structures and amounts of lipid A among the strains suggested a relationship between lipid A profiles and the phylogenetic classification of the strains.

Chemical attribution of fentanyl: The effect of human metabolism

Chemical attribution typically aims to establish a link between material found at a crime scene and a person, location or other evidence. In the field of illicit drugs, chemical attribution signatures are usually impurity profiles. Extending these to metabolized samples would create new possibilities in forensic investigations. The present study explores the effect of human metabolism on the impurity profile of fentanyl, as representative of synthetic opioids. Two different methods (Gupta and Siegfried) were used to synthesize fentanyl, after which the samples were incubated with liver microsomes to mimic human metabolism. The impurity profiles have been characterized with gas chromatography-mass spectrometry (GC-MS), gas chromatography with flame ionization detector (GC-FID), liquid chromatography quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) and liquid chromatography orbitrap mass spectrometry (LC-Orbitrap-MS). It was found that GC-FID and LC-Orbitrap-MS can both be used to discriminate between the Gupta and Siegfried synthesis method. This holds both for the analyses performed before and after metabolism. In addition, principal component analysis (PCA) identified acetyl fentanyl as the most important marker compound. Associated detection limits are in the range of concentrations expected in case work. While acetyl fentanyl is not stable during metabolism, its discriminating potential is transferred to its metabolic product acetyl norfentanyl. In addition, the stable impurities phenylacetamide and 1-phenylethylpiperidin-4-ol were found to be significant classifiers. To implement the results in a forensic framework, linear discriminant analysis (LDA) was applied and used to establish likelihood ratios. To our knowledge, the present work demonstrates for the first time the possibility of chemical attribution of drugs through the analysis of metabolic trace levels in biological samples.

A metabolomics approach to evaluate post‐fermentation enhancement of daidzein and genistein in a green okara extract

Okara is a major agri-industrial by-product of the tofu and soymilk industries. Employing food-wastes as substrates for the green production of natural functional compounds is a recent trend that addresses the dual concepts of sustainable production and a zero-waste ecosystem. Extracts of unfermented okara and okara fermented with Rhizopus oligosporus were obtained using ethanol as extraction solvent, coupled with ultrasound sonication for enhanced extraction. Fermented extracts yielded significantly better results for total phenolic content (TPC) and total flavonoid content (TFC) than unfermented extracts. A qualitative liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis revealed a shift from glucoside forms to respective aglycone forms of the detected isoflavones, post-fermentation. Since the aglycone forms have been associated with numerous health benefits, a quantitative high-performance liquid chromatography (HPLC) analysis was performed. Fermented okara extracts had daidzein and genistein concentrations of 11.782 ± 0.325 μg mL-1 and 10.125 ± 1.028 μg mL-1 , as opposed to that of 6.7 ± 2.42 μg mL-1 and 4.55 ± 0.316 μg mL-1 in raw okara extracts, respectively. Lastly, the detected isoflavones were mapped to their metabolic pathways, to understand the biochemical reactions triggered during the fermentation process. Fermented okara may be implemented as a sustainable solution for production of natural bioactive isoflavonoids genistein and daidzein. © 2021 Society of Chemical Industry.

Preparative isolation, fractionation and chemical characterization of dissolved organics from natural and industrially derived bitumen-influenced groundwaters from the Athabasca River watershed

Recent analytical advances have provided evidence that groundwater affected by oil sands process-affected water (OSPW) is reaching the Athabasca River at one location. To understand and discriminate the toxicological risks posed by OSPW-influenced groundwater relative to groundwaters associated with natural oil sands deposits, these highly complex mixtures of soluble organics were subjected to toxicological characterization through effects directed analysis. A recently-developed preparative fractionation methodology was applied to bitumen-influenced groundwaters and successfully isolated dissolved organics from both industrial and natural sources into three chemically distinct fractions (F1, F2, F3), enabling multiple toxicological assessments. Analytical techniques included electrospray ionization high resolution mass spectrometry (ESI-HRMS), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF/MS), gas chromatography mass spectrometry (GC–MS), and synchronous fluorescence spectroscopy (SFS) methods, which did not reveal obvious differences between sources. Comparisons between fractions within each source consistently demonstrated that F3 contained compounds with greater polarity than F2, which in turn was more polar than F1. The abundance of O2 species was confined to F1, including naphthenic acids often cited for being the primary toxicants within bitumen-influenced waters. This result is consistent with earlier work on aged OSPW, as well as with other extraction methods, suggesting that additional factors other than molecular weight and the presence of acid functionalities play a prominent role in defining compound polarities and toxicities within complex bitumen-derived organic mixtures. The similarities in organic abundances, chemical speciation, aromaticity, and double bond equivalents, concomitant with inorganic mixture similarities, demonstrate the resemblances of bitumen-influenced groundwaters regardless of the source, and reinforce the need for more advanced targeted analyses for source differentiation. • Method for extraction and fractionation of dissolved organics was applied to bitumen-influenced groundwater samples • Dissolved organics are considered principal toxic components in OSPW • Three large volume organic fractions were generated and characterized by complement of methodologies • Isolated fractions increased in polarity and degree of aromaticity • Chemical composition was similar between groundwaters influenced by OSPW and/or natural bitumen sources

Rapid screening and confirmation of 415 pesticide residues in red cabbages by liquid chromatography-quadrupole-time of flight-mass spectrometry

应用液相色谱-四极杆-飞行时间质谱(LC-QTOF/MS)建立了一次进样可同时对紫甘蓝中415种农药残留进行快速筛查和准确确证的分析方法。实验采用1%(v/v)醋酸乙腈溶液提取,无水硫酸镁和氯化钠进行盐析,ZORBAX SB-C18色谱柱(100 mm×2.1 mm, 3.5 μm)分离,以0.1%(v/v)甲酸水溶液(含5 mmol/L乙酸铵)-乙腈为二元流动相进行梯度洗脱,应用LC-QTOF/MS在电喷雾电离、全离子MS/MS(All Ions MS/MS)扫描正模式下进行检测,基质匹配外标法定量分析。通过优化全自动MS/MS采集模式(Auto MS/MS)和全离子MS/MS采集模式下的不同参数,得到每种采集模式下的最佳条件。然后在2种不同采集模式的最佳条件下对比,最终选取All Ions MS/MS采集模式。实验结果表明,采用所建立的分析方法可以准确定性和定量筛查紫甘蓝中415种农药残留,所有415种农药在各自的范围内线性相关系数(r2)均大于0.990,其中411种农药的筛查限(SDL)≤5 μg/kg, 413种农药的定量限(LOQ)≤10 μg/kg。在1倍、2倍和10倍LOQ添加水平下,农药的回收率分别为65.7%~118.4%、72.0%~118.8%和70.2%~111.2%,相对标准偏差分别为0.9%~19.7%、0.2%~19.9%和0.6%~19.9%。将该方法应用于2019年欧盟能力验证项目的紫甘蓝样品中未知农药残留筛查方法和定量方法考核样的检测,所有添加农药均被准确定性筛查和定量检测,没有假阳性和假阴性。结果表明,该方法快速、准确、可靠,适用于对紫甘蓝中多种农药残留的高通量定性筛查和准确定量,可以扩展到其他果蔬基质中多农残的高通量筛查。

Metabolic Profiling of Vasorelaxant Extract from Malvaviscus arboreus by LC/QTOF-MS.

We aimed to develop a standardized methodology to determine the metabolic profile of organic extracts from Malvaviscus arboreus Cav. (Malvaceae), a Mexican plant used in traditional medicine for the treatment of hypertension and other illnesses. Also, we determined the vasorelaxant activity of these extracts by ex vivo rat thoracic aorta assay. Organic extracts of stems and leaves were prepared by a comprehensive maceration process. The vasorelaxant activity was determined by measuring the relaxant capability of the extract to decrease a contraction induced by noradrenaline (0.1 μM). The hexane extract induced a significant vasorelaxant effect in a concentration- and endothelium-dependent manner. Secondary metabolites, such as polyunsaturated fatty acids, terpenes and one flavonoid, were annotated by liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS) in positive ion mode. This exploratory study allowed us to identify bioactive secondary metabolites from Malvaviscus arboreus, as well as identify potentially-new vasorelaxant molecules and scaffolds for drug discovery.

LC-Q-TOF/MS based identification and in silico verification of ACE-inhibitory peptides in Giresun (Turkey) hazelnut cakes

Hazelnut (Corylus avellana L.) cakes represent are a rich source of proteins. In an effort to valorize industrially cold-pressed hazelnut cakes, angiotensin-converting enzyme (ACE) inhibitory characteristics of hazelnut protein hydrolysates were evaluated. Trypsin, chymotrypsin and thermolysin hydrolysates of hazelnut protein isolates were fractionated using Fast Protein Liquid Chromatography (FPLC). The hydrolysate fractions were tested for ACE inhibitory characteristics and inhibitor peptide identification was based on Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-Q-TOF/MS). Finally, in vitro ACE inhibitory activity was verified using in silico tools. In all cases, some hydrolysate fractions demonstrated ACE inhibitory characteristics, while inhibitory activity widely varied (7–95%) depending on proteolysis conditions. In ACE inhibitory fractions, 179 different peptides were identified. Their potential inhibitory activity was verified in silico for 22 different peptides generated by thermolysin, 3 for chymotrypsin and 4 for trypsin. While the half maximal inhibitory concentration (IC50) (0.13–4.83 mg ml−1) values were comparable to the previous literature, currently identified sequences were different than ACE inhibitory peptides purified from Asian hazelnuts. The peptides with the highest PeptideRanker scores for each treatment (i.e., SPLAGR, VPHW and PGHF) were studied for their potential ACE binding, Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) and circulatory half-life characteristics demonstrating limited pharmokinetic interference, low toxicity as well as comparable short circulation and stronger binding compared to a reference inhibitor peptide (i.e., VPP). Geographical attributes and proteolytic treatments could have a bearing on ACE inhibitory potential of peptides, while hazelnut cakes can be regarded as a valuable resource for ACE inhibitor peptides.

High-Efficiency and Ground-State Atomic Oxygen-Dominant Photodegradation of Carbamazepine by Coupling Chlorine and g-C3N4

In this study, a solar/chlorine/graphitic carbon nitride (g-C3N4) system for the highly efficient degradation of carbamazepine (CBZ) was constructed, and the degradation mechanism of CBZ in this system was elucidated. The removal rate of CBZ by g-C3N4 combined with solar/chlorine was as high as 97.8%, which was more than twice that of the solar/chlorine combined system (43.8%). Electron spin resonance analysis revealed that the hydroxyl radicals (HO•) in the solar/chlorine/g-C3N4 system were remarkably less than that in the solar/chlorine photocatalytic system, wherein HO• was the dominant participant. However, the former system had higher efficiency than the latter. Scavenging tests confirmed the existence of a synergistic effect between solar/chlorine and g-C3N4 in CBZ degradation, and ground-state atomic oxygen (O(3P)) played a more important role than HO• in the solar/chlorine/g-C3N4 system. A novel O3-related pathway of CBZ degradation was proposed on the basis of the determination of intermediates. The intermediates detected via liquid chromatography quadrupole time of flight mass spectrometry (LC/Q-TOF-MS)/MS analysis indicated that O3 attacked the double bond of CBZ via the Criegee mechanism and produced intermediates with two new aldehydes. This study not only improved the knowledge of the effects of O(3P) and the O(3P)-related degradation mechanism of organic pollutants but also provided a reminder that O(3P) might be overlooked in the photocatalytic processes, especially in processes that occur in the presence of dissolved oxygen or oxygen-containing anions.

Enhanced activated persulfate oxidation of ciprofloxacin using a low-grade titanium ore under sunlight: influence of the irradiation source on its transformation products.

In this work, the activated persulfate oxidation of ciprofloxacin (CIP) using a low-grade titanium ore under sunlight or simulated sunlight were conducted to analyze the CIP degradation efficiency and to identify the transformation products (TPs) generated during oxidation under both types of irradiation sources by using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). All advance oxidation process experiments were performed in a 2700-mL raceway reactor at a pH value of ~ 6.5 and an initial CIP concentration of 1mg/L, during 90min of reaction time. The control experiments carried out under simulated sunlight achieved a 97.7 ± 0.6% degradation efficiency, using 385W/m2 of irradiation with an average temperature increase of 11.7 ± 0.6°C. While, the experiments under sunlight reached a 91.2 ± 1.3% degradation efficiency, under an average irradiation value of 19.2 ± 0.3W/m2 in October-November 2019 at hours between 11:00 am and 3:00 pm with an average temperature increase of 1.4 ± 0.8°C. Mass spectrometry results indicated that 14 of the 108 possible TPs reported in the literature were detected. The calculated exact mass, measured accurate mass, and its characteristic diagnostic fragment ions were listed, and two new TPs were tentative identified. The TP generation analysis showed that some specific compounds were detected in different time intervals with kinetic variations depending on the irradiation used. Consequently, two CIP degradation pathways were proposed, since the type of irradiation determines the CIP degradation mechanism. Graphical abstract.

Plasma amino acids indicate glioblastoma with ATRX loss.

Glioblastoma (GB) is the most common primary brain tumour in adults. The lack of molecular biomarker, non-specific symptoms and fast growth rate often result in asignificant delay in diagnosis. Despite multimodal treatment, the prognosis remains poor. Here, we verified the hypothesis that amino acids (AA) regulating the critical metabolic pathways necessary for maintenance, growth, reproduction, and immunity of an organism, may constitute afavourable target in GB biomarker research. We measured the plasma amino acids levels in 18GB patients and 15 controls and performed the quantitative and qualitative metabolomic analysis of free AA applying high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). We present both the raw data and the results of our statistical analysis. The majority of AA were lowered in the study group in comparison to the control group. Five of these (arginine, glutamic acid, glutamine, glycine, and histidine) differed significantly (all p < 10-5 and AUC > 0.9). Plasma levels of leucine and phenylalanine decreased in the case of GB with lost alpha-thalassemia/mental retardation X-linked (ATRX) expression on immunohistochemistry (p = 0.003 and 0.045, respectively). We demonstrated for the first time that certain plasma-free AA levels of GB patients were significantly different from those in healthy volunteers. Target profiling of plasma-free AA, identified utilizing LC-QTOF-MS, may present prognostic value by indicating GB patients with lost ATRX expression. Theon-going quest for glioma biomarkers still aims to determine the detailed metabolic profile and evaluate its impact on therapy and prognosis.

Evaluation of CYP2D, CYP1A2 and distribution of tetrandrine, fangchinoline in the brain, liver, and kidney of wistar rats after short-term exposure to Cyclea peltata

Background: Cyclea peltata (CP) roots are used in Indian traditional medicine to treat various diseases. However, short-term toxic effects of CP are completely unknown. Objectives: The aim of this study is to evaluate short-term toxic effects of CP, tissue distribution of bioactive alkaloids tetrandrine, fangchinoline in the brain, liver, kidney, and mRNA expression of CYP2D, CYP1A2 after CP administration. Materials and Methods: In vitro toxicity evaluation of CP was carried out using annexin 5/propidium iodide assay with or without CP treatment in L 929 cell line. And in vivo short term toxicity of CP was evaluated in Wistar rats for 28 days. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) based tissue distribution of bioactive molecules was assessed and mRNA expression of CYP1A2, CYP2D, CYP2C6, and CYP2E1 were estimated using qRT- polymerase chain reaction. Results: In vitro toxicity of 70% aqueous ethanol extract of CP 50 μg/mL showed 62.18% cell viability. Oral administration of CP (50, 500 mg/kg) did not cause any clinical, hematological, serum biochemical, and histopathological changes in rats, whereas CP (1000 mg/kg) showed infiltrative changes in the kidney and lungs. Imbalance in oxidative stress and antioxidant defense was reflected as elevated MDA levels in rat liver. LC-Q-TOF-MS studies could detect tissue distribution of bioactive alkaloids tetrandrine, fangchinoline and their decomposed masses in the liver and kidney, whereas tetrandrine and its decomposed molecule (580.3) ([M + H]-43) + could cross blood–brain barrier and were detected in the brain. Evaluation of mRNA expression revealed dose-dependent increase in expression of CYP2D and CYP1A2. Conclusion: Oral administration of CP 500 mg/kg for 28 days is safer in rats due to balanced antioxidant defense. Imbalance in antioxidant defense enzymes and toxic metabolites formed through the escalation of CYP2D, CYP1A2 and metabolism of bioactive alkaloids of CP may be the reason for infiltrative changes in kidney, lungs observed after 28 days CP 1000 mg/kg administration.

Immunomodulatory effect of the hydroalcoholic extract of Abrus precatorius L. leaves against cyclophosphamide-induced immunosuppression in mice

This study presents the immunomodulatory potential of Abrus precatorius Linn. (Indian wild licorice) leaves. A hydroalcoholic extract of A. precatorius leaves (EAPL) was prepared by maceration. Thirty male mice were divided into five groups as follows: control group, model control group (cyclophosphamide-treated), and three treatment groups (treated with EAPL at doses of 100, 200 and 300 mg/kg, per os, daily for 14 days). Parameters, including hematological, biochemical, organ indices, hemagglutination test (HA titer), delayed-type hypersensitivity (DTH), interleukin-2 (IL-2) level, splenocyte proliferation and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis were evaluated. Histopathological examination was carried out for the spleen, kidney and liver. Cyclophosphamide (CPMD)-induced changes in white blood cells, lymphocytes and platelets were improved in the treatment groups. Total protein and albumin levels in the treatment groups were significantly higher. EAPL treatment significantly stimulated splenic T-lymphocytemediated proliferation. Neutrophil adhesion was insignificantly decreased in the model control group compared to the normal control group, which was slightly improved by EAPL treatment. EAPL treatment significantly improved the HA titer and cell-mediated immunity, which is an indication of antibody production. The IL-2 level was significantly higher in the treatment groups that received 200 and 300 mg/kg EAPL. LC-QTOF-MS analysis of EAPL showed the presence of flavonoids, lignans, iridoids and phenolic glycosides. These results suggest that A. precatorius leaves are a good candidate for a new immunomodulatory herbal formulation.

Biological Activity of the Extracts from Pecan Shelling Industry Byproducts

HighlightsThe first study on characterization of the extracts obtained from industrial pecan nut processing byproducts.Chemical composition and biological activity of the extracts varied with type of byproduct and the pecan cultivars used in the process.Pecan shell extracts exhibited anticancer, antioxidant, and antimicrobial activity.Abstract. Industrial processing of pecan nuts produces large amounts of shells, which have economic significance for pecan growers and processors. Hence, it is imperative that valorization of pecan processing byproducts is explored. In this study, byproducts from commercial pecan shelling operations were evaluated as potential sources of biologically active phytochemicals. Shelling byproducts from Pawnee, Native, and Stuart cultivars were examined. Aqueous ethanol shell extracts were analyzed for their chemical composition using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). Total phenolic content, DPPH radical scavenging capacity, anticancer activity, and antimicrobial activity of the samples were investigated. The chemical composition and biological activity of the shell extracts varied significantly with the pecan cultivar and type of byproduct stream used in the study. The presence of nut meat pieces in the byproducts resulted in high oil content in the extracts. The extract from Pawnee cultivar showed high DDPH activity, low IC50 for cancer cell lines, and high IC50 for the healthy cell line (Vero). Extracts from all cultivars had antimicrobial activity against Escherichia coli at relatively high disk loadings. This is the first study on the biological activity of extracts obtained from commercial pecan shelling byproducts. The findings of this study have significant practical implications and provide the initial data much needed for valorization of industrial pecan shelling byproducts. Keywords: Anticancer activity, Antimicrobial activity, Chemical composition, Pecan shell extract.

Metabolic analysis of the illegal analogues of anti-obesity drugs using LC-Q-TOF-MS/MS

With an increase in the obese population, the indiscriminate demand for anti-obesity drugs for rapid weight loss or maintenance has grown. As a result, illegal substances that could induce unexpected negative health effects or fatal side effects are being produced and mixed into consumer products. In the present study, the metabolites of five major illegal anti-obesity drugs are analyzed for the first time. Our data can be utilized to identify related compounds and predict their toxicological effects. Didesmethylsibutramine, desmethylsibutramine, homosibutramine, chlorosibutramine, and benzylsibutramine were metabolized in in vitro and in vivo models, and the metabolites were identified using liquid chromatography quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) and tandem mass spectrometry (LC-Q-TOF-MS/MS). The in vivo metabolite analysis was carried out using urine and feces samples from rats, and the in vitro metabolite analysis was performed by incubating the analogues with human liver microsomes. We found that each sibutramine analogue was metabolized into several constituents: 2 (M1–2), 5 (M1–5), 11 (M1–11), 7 (N1–7), and 5 (O1–5). In conclusion, our metabolic study could be used for toxicological detection of illegal obesity treatments and metabolite identification in forensic cases.

New flavane gallates from the aerial part of an African/Arabian medicinal plant Plicosepalus curviflorus by LC-MS and NMR based molecular characterization

Plicosepalus curviflorus is distributed in Africa, Yemen and Saudi Arabia and applied to treat cancer, tonsillitis, otitis media and for curing diabetes. The objective of this study is to isolate chemical constituents from this medicinally important plant and it yielded one undescribed gallocatechin derivative 1 along with nine known compounds 2–10. In this study, the metabolite profiling of n-butanol fraction of P. curviflorus was also measured by using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOf-MS). Our research provided the facts for the theory that this plant is a good source of flavane and flavonoids and can be used as medicine. This application allowed to unambiguously identify eight compounds 11–18 from n-butanol soluble fraction of P. curviflorus. We describe here complete characterization of one new compound isolated from the n-butanol soluble fraction of P. curviflorus by NMR and ESI-MS. To the best of our good grasp, compounds 12–15, represents the example of substituted catechin derivatives identified by LC-QTOf-MS method.

Understanding the pathophysiological changes via untargeted metabolomics in COVID-19 patients.

Coronavirus disease 2019 (COVID-19) is an infectious respiratory disease caused by anew strain of the coronavirus. There is limited data on the pathogenesis and the cellular responses of COVID-19. In this study, weaimedto determine the variation of metabolites between healthy control and COVID-19 via the untargeted metabolomics method. Serum samples were obtained from 44 COVID-19 patients and 41 healthy controls. Untargeted metabolomics analyses were performed by the LC/Q-TOF/MS (liquid chromatography quadrupole time-of-flight mass spectrometry) method. Data acquisition, classification, and identification were achieved by the METLIN database and XCMS. Significant differences were determined between patients and healthy controls in terms of purine, glutamine, leukotriene D4 (LTD4), and glutathione metabolisms. Downregulations were determined in R-S lactoglutathione and glutamine. Upregulations were detected in hypoxanthine, inosine, and LTD4. Identified metabolites indicate roles for purine, glutamine, LTD4, and glutathione metabolisms in the pathogenesis of the COVID-19. The use of selective leukotriene D4 receptor antagonists, targeting purinergic signaling as a therapeutic approach and glutamine supplementation may decrease the severity and mortality of COVID-19.

Novel Photosynthesis And Characterization of 4-(5,7- Dichloro-8ah-chromene-2-yl)-n, N-dimethylaniline from Its Chalcone Isomer

In the present study, trans-3-(2,4-dichlorophenyl)-1-(4-(dimethylamino)phenyl)prop-2-en-1-one (trans 2,4-dimethyl amino chalcone) was synthesized by Claisen-Schmidt reaction in the presence of aqueous alcoholic alkali solution by condensation of a substituted acetophenone with substituted benzaldehydes, Then, The photosynthesis of 4-(5,7-dichloro-8aH-chromen-2-yl)-N,N-dimethylaniline (2,4-dimethylamino chromene) was accomplished from the irradiation of the( trans 2,4-dimethyl amino chalcone) with xenon light. The products were characterized by UV-Visible, FT-IR, 1HNMR, thin layer chromatography Elemental analysis(CHNO) and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-ToF-MS).

N-nitrosodimethylamine formation potential (NDMA-FP) of ranitidine remains after chlorination and/or photo-irradiation: Identification of transformation products in combination with NDMA-FP test

N-nitrosodimethylamine (NDMA), a probable carcinogenic disinfection by-product, can be formed with high molar yields following chloramination of ranitidine (RNTD), a histamine H2-receptor antagonist. Although RNTD and some of its transformation products (TPs) have been studied under chlorination and photo-irradiation, the relationship between RNTD TPs and NDMA formation potential (NDMA-FP) remaining after those processes is still unclear. This study investigated the effects of chlorination and/or photo-irradiation on NDMA-FP derived from RNTD, simulating an urban water environment receiving treated wastewater. After chlorination and/or photo-irradiation of RNTD, ten TPs including five new ones were identified by liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QTof-MS). In addition, important RNTD TPs responsible for NDMA-FP (e.g., chlorinated and hydroxylated RNTD: TP-364) were also confirmed by the relationship between detected peak area and NDMA-FP. The results showed that NDMA-FP remained due to the presence of RNTD TPs, although RNTD itself was significantly removed by chlorination and/or photo-irradiation. TP-364 was only formed by chlorination of RNTD and could not be removed by photo-irradiation. TP-314 (a stereoisomer of RNTD), -299, and -286, which were mainly formed by photo-irradiation of RNTD but not by photo-irradiation after chlorination, had strong positive correlations with NDMA-FP (R2 > 0.90; F-test, P < 0.01).

Metabolic Drug Response Phenotyping in Colorectal Cancer Organoids by LC-QTOF-MS

As metabolic rewiring is crucial for cancer cell proliferation, metabolic phenotyping of patient-derived organoids is desirable to identify drug-induced changes and trace metabolic vulnerabilities of tumor subtypes. We established a novel protocol for metabolomic and lipidomic profiling of colorectal cancer organoids by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) facing the challenge of capturing metabolic information from a minimal sample amount (<500 cells/injection) in the presence of an extracellular matrix (ECM). The best procedure of the tested protocols included ultrasonic metabolite extraction with acetonitrile/methanol/water (2:2:1, v/v/v) without ECM removal. To eliminate ECM-derived background signals, we implemented a data filtering procedure based on the p-value and fold change cut-offs, which retained features with signal intensities >120% compared to matrix-derived signals present in blank samples. As a proof-of-concept, the method was applied to examine the early metabolic response of colorectal cancer organoids to 5-fluorouracil treatment. Statistical analysis revealed dose-dependent changes in the metabolic profiles of treated organoids including elevated levels of 2′-deoxyuridine, 2′-O-methylcytidine, inosine and 1-methyladenosine and depletion of 2′-deoxyadenosine and specific phospholipids. In accordance with the mechanism of action of 5-fluorouracil, changed metabolites are mainly involved in purine and pyrimidine metabolism. The novel protocol provides a first basis for the assessment of metabolic drug response phenotypes in 3D organoid models.