Positive Mode Research Articles

High-coverage characterization and discovery of molecular markers for quality control of natural fragrant plant extracts using UPLC-HRMS-based untargeted metabolomics.

The chemical components of natural fragrant plant extracts are of high complexity, and the strategies for quality control (QC) and further discovery of fragrance mechanisms still need to be further investigated. This study integrated the strategies and methods of untargeted metabolomics and chemometrics and statistical modeling to attain the goal. The techniques of reversed-phase and HILIC analysis of ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS) were simultaneously used to collect data in both positive and negative ion modes. The pattern analysis of fingerprints and discovery of characteristic molecular markers for QC analysis were comprehensively employed to reach in-depth analysis of the quality variation and discovery of differential molecules among natural fragrant plant extracts. The former uses fingerprint technique to analyze their overall similarities and differences, and the latter comprehensively discovers molecular substances characterizing the chemical characteristics of fragrant extracts with the help of metabolomics and univariate and multivariate methods. The findings are expected to be used as the molecular markers in product manufacturing, sales, and consumption to achieve accurate quality control and recognition of targeted molecules for potential quality monitoring using spectroscopy techniques. In this work, 27 natural fragrant extracts were applied as examples, and their chemical components were comprehensively analyzed with discovery of markers for quality control. After data integration, 1178 molecules were annotated, and 267 differential metabolite molecules with the values of variable importance in the projection (VIP) larger than 1.0 were found. The results show that the method proposed in this work is of great significance for high-coverage analysis, QC marker discovery, and aroma mechanism elucidation, which has potential applications in the areas of food, cosmetics, pharmaceuticals, tobacco, and others.

Validated UPLC-MS/MS method for quantification of melatonin receptor agonists and dual orexin receptor antagonists in human plasma and breast milk: Application to quantify suvorexant and lemborexant in clinical samples

Pharmaceutical care is important for mental health during the perinatal period, which is often characterized by insomnia. In recent years, prescriptions of melatonin receptor agonists (MRAs) and dual orexin receptor antagonists (DORAs) for insomnia have increased; however, their use during the perinatal period has scarcely been reported. In the present study, we developed a UPLC-MS/MS method for the quantification of ramelteon, its metabolite M-II, suvorexant, and lemborexant in human plasma and breast milk to accumulate information on the safety and transfer of MRAs and DORAs into breast milk. Samples of MRAs (ramelteon and M-II) in plasma and breast milk were prepared using liquid–liquid extraction (LLE) with ethyl acetate. For DORAs (suvorexant and lemborexant), LLE with ethyl acetate was applied to plasma samples. For breast milk samples, significant ion suppression was observed for LLE with ethyl acetate. Solid-phase extraction (SPE) cartridges capable of removing phospholipids improved the matrix effects. Finally, protein precipitation with methanol and an SPE cartridge, InertSep® Phospholipid Remover, were selected for breast milk sample preparation. An ACQUITY UPLC BEH C18 column was used for analyte separation. MRAs and DORAs were eluted using isocratic and gradient elution, respectively, and analyzed using electrospray ionization in the positive mode with multiple reaction monitoring. The range of calibration curve for MRAs and DORAs was 0.1–25 and 0.5–50 ng/ml, respectively. Both the plasma and breast milk samples exhibited good linearity over this range. The method was validated by evaluating its accuracy and precision, matrix effect, recovery, carry-over, stability, and dilution integrity. The validated method was successfully applied to clinical samples donated by breastfeeding women and the milk/plasma (M/P) ratio and relative infant dose (RID) of lemborexant (one case) and suvorexant (two cases) were estimated. The M/P ratio of lemborexant was <1, and the RID was 1.05 %. The M/P ratio of suvorexant was <0.1, and RID was 0.11–0.20 %. This method will be useful for future studies evaluating the safety of these drugs during breastfeeding.

Unraveling the Roles of Ionic Size and Hydrogen Bonding in Electric Field-Driven Ion Emission from Hydroxylamine Nitrate-Based Ionic Liquids.

Ionic size and hydrogen bonding (HB) may play significant roles in controlling ion emission from HAN (hydroxylamine nitrate)-based ionic liquids (ILs) but have received little attention. In this paper, the ion emission behavior and mechanism in an external electric field are meticulously investigated using the molecular dynamics (MD) method and density functional theory. We find that the higher the proportion of ionic HAN in the blend of ILs, the longer the delay time of the ion start-up emission. In the positive mode, cations can evaporate directly from the surface of the studied ILs and manifest exclusively as the [EMIM]+ monomers within the simulation time scale, whereas in the negative mode, a variety of complicated anion clusters are emitted. As a result, the average charge-to-mass ratio of the positively charged species remarkably exceeds that of the negatively charged species. This large difference is attributed to the relatively larger size of the [EMIM]+ ion and the absence of substantial HB interactions between the [EMIM]+ ion and any other monomer, leading to diminished binding energies. Conversely, the strong HB interactions, primarily constituted by N-H--O and O-H--O hydrogen bonds, are clearly found in the [EtSO4]--based and HAN-based clusters. In addition, the [NO3]- and [EtSO4]- ions tend to combine with the small-sized [HA]+ ions to form large anion clusters rather than with the [EMIM]+ ions. The energy decomposition results further elucidate that the orbital interaction plays a pivotal role in the [NO3]- and [EtSO4]--based clusters. The findings clearly elucidate the experimental phenomena observed in previous studies and have implications for the formulation of multimode IL propellants.

Metabolomics analysis of patients with Schistosoma japonicum infection based on UPLC-MS method

BackgroundSchistosomiasis is still one of the most serious parasitic diseases. Evidence showed that the metabolite profile in serum can potentially act as a marker for parasitic disease diagnosis and evaluate disease progression and prognosis. However, the serum metabolome in patients with Schistosoma japonicum infection is not well defined. In this study, we investigated the metabolite profiles of patients with chronic and with advanced S. japonicum infection.MethodsThe sera of 33 chronic S. japonicum patients, 15 patients with advanced schistosomiasis and 17 healthy volunteers were collected. Samples were extracted for metabolites and analyzed with ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).ResultsWe observed significant differences in metabolite profiles in positive and negative ion modes between patients with advanced and chronic S. japonicum infection. In patients with chronic S. japonicum infection, 199 metabolites were significantly upregulated while 207 metabolites were downregulated in advanced infection. These differential metabolites were mainly concentrated in steroid hormone biosynthesis, cholesterol metabolism and bile secretion pathways. We also found that certain bile acid levels were significantly upregulated in the progression from chronic to advanced S. japonicum infection. In receiver operator characteristic (ROC) analysis, we identified three metabolites with area under the curve (AUC) > 0.8, including glycocholic (GCA), glycochenodeoxycholate (GCDCA) and taurochenodeoxycholic acid (TCDCA) concentrated in cholesterol metabolism, biliary secretion and primary bile acid biosynthesis.ConclusionsThis study provides evidence that GCA, GCDCA and TCDCA can potentially act as novel metabolite biomarkers to distinguish patients in different stages of S. japonicum infection. This study will contribute to the understanding of the metabolite mechanisms of the transition from chronic to advanced S. japonicum infection, although more studies are needed to validate this potential role and explore the underlying mechanisms.Graphical

Prioritization, Identification, and Quantification of Emerging Contaminants in Recycled Textiles Using Non-Targeted and Suspect Screening Workflows by LC-ESI-HRMS.

Recycled textiles are becoming widely available to consumers as manufacturers adopt circular economy principles to reduce the negative impact of garment production. Still, the quality of the source material directly impacts the final product, where the presence of harmful chemicals is of utmost concern. Here, we develop a risk-based suspect and non-targeted screening workflow for the detection, identification, and prioritization of the chemicals present in consumer-based recycled textile products after manufacture and transport. We apply the workflow to characterize 13 recycled textile products from major retail outlets in Sweden. Samples were extracted and analyzed by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). In positive and negative ionization mode, 20,119 LC-HRMS features were detected and screened against persistent, mobile, and toxic (PMT) as well as other textile-related chemicals. Six substances were matched with PMT substances that are regulated in the European Union (EU) with a Level 2/3 confidence. Forty-three substances were confidently matched with textile-related chemicals reported for use in Sweden. For estimating the relative priority score, aquatic toxicity and concentrations were predicted for 7416 features with tandem mass spectra (MS2) and used to rank the non-targeted features. The top 10 substances were evaluated due to elevated environmental risk linked to the recycling process and potential release at end-of-life.

Effects of Network-based Positive Psychological Nursing Model on Negative Emotions, Cancer-related Fatigue, and Quality of Life in Cervical Cancer Patients with Post-operative Chemotherapy.

Cervical cancer patients with post-operative chemotherapy experience anxiety, depression, and cancer-related fatigue, leading to a decline in their quality of life and posing challenges to the rehabilitation of patients. Therefore, it is necessary to explore effective nursing methods. This study aimed to investigate the effects of a web-based positive psychological nursing model on negative emotions, cancer-related fatigue, self-management efficacy, treatment compliance, and quality of life among cervical cancer patients with post-operative chemotherapy. This retrospective study included 101 cervical cancer patients who underwent surgical intervention at our hospital between January 2019 and December 2023. Patients who received the usual mode of care were included in the control group (n = 48), while those who received the web-based positive psychological care mode were included in the study group (n = 53). For all study subjects, various assessment indices were evaluated, including baseline characteristics, treatment adherence, and the Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), Revised Piper Fatigue Scale (RPFS), the Chinese version of the Strategies Used by Patients to Promote Health (C-SUPPH), and European Organization for Research and Treatment of Cancer Quality of Life questionnaire -Core 30 (EORTC QLQ-C30). Additionally, anxiety/depression, cancer-related fatigue, self-management efficacy, treatment compliance, and quality of life were compared between the two groups. After the intervention, the HAMA score, HAMD score, and RPFS score were significantly decreased for both groups compared to before intervention (p < 0.05). However, the C-SUPPH score was significantly increased than before intervention (p < 0.05). We observed that HAMA, HAMD, and RPFS scores were substantially lower in the study group than those in the control group after intervention (p < 0.05). In contrast, C-SUPPH scores were significantly higher (p < 0.05). After the intervention, treatment compliance was significantly better in the study group compared to the control group. Furthermore, the EORTC QLQ-C30 score was substantially higher than that of the control group (p < 0.05). The network-based positive psychological nursing model can effectively alleviate negative emotions and cancer-related fatigue in cervical cancer patients who have undergone post-operative chemotherapy, thereby improving their quality of life. Additionally, this model improves patients' self-management effectiveness and treatment compliance. These findings provide novel insights into the nursing of cervical cancer patients with post-operative chemotherapy, underscoring its clinical significance.

Pharmacokinetics and Bioavailability Study of a Novel Smoothened Inhibitor TPB15 for Treatment of Triple-Negative Breast Cancer in Rats by High Performance Liquid Chromatography-Mass Spectrometry.

Smoothened (SMO), a key component of the hedgehog signaling pathway, represents a therapeutic target for triple negative breast cancer(TNBC), yet the chemotherapy response rate in TNBC patients is only 40-50%, underscoring the urgent need for the development of novel drugs to effectively treat this condition. The novel compound TPB15, an SMO inhibitor derived from [1,2,4] triazolo [4,3-α] pyridines, demonstrated superior anti-TNBC activity and lower toxicity compared to the first SMO inhibitor vismodegib in both in vitro and in vivo. However, the compound's pharmacokinetic properties remain unclear. The present work aims to develop a simple HPLC-MS/MS method to profile the pharmacokinetics and bioavailability of TPB15 in rats as a ground work for further clinical research. Separation was performed on an Agilent ZORBAX StableBond C18 column by gradient elution using acetonitrile and 0.1% formic acid as mobile phase at a flow rate of 0.3mL/min. Multiple reaction monitoring(MRM) in positive mode with the transitions of m/z 454.2 → 100.0, 248.1 → 121.1 was employed to determine TPB15 and internal standard tinidazole, respectively. The specificity, intra- and inter- day precision and accuracy, extraction recovery, stability, matrix effect, dilution integrity and carryover of the method was validated. The pharmacokinetics and bioavailability studyof TPB15 were carried out on rats through intravenous injection at the dose of 5 mg/kg and oral gavage at the dose of 25 mg/kg, and the pharmacokinetics parameters were calculated by the non-compartment analysis using the pharmacokinetics software DAS 2.1.1. The values of specificity, intra- and inter- day precision and accuracy, extraction recovery, stability, matrix effect, dilution integrity and carryover satisfied the acceptable limits. The lower limit of quantification of this method was 10 ng/mL with a linear range of 10-2000ng/mL. The validated method was then applied to pharmacokinetics and bioavailability studies in rat by dosing with gavage (25mg/kg) and intravenous injection(5mg/kg), and the oral bioavailability of TBP15 in rat was calculated as 16.4 ± 3.5%. The pharmacokinetic parameters were calculated as following: maximum of plasma concentration (Cmax) (PO: 2787.17 ± 279.45µg/L), Time to maximum plasma concentration (Tmax) (PO: 4.20 ± 0.90 h), the area under the concentration-time curve 0 to time (AUC0-t) (PO: 17,373.03 ± 2585.18 ng/mL·h, IV: 21,129.79 ± 3360.84ng/mL·h), the area under the concentration-time curve 0 to infinity (AUC0-∞) (PO: 17,443.85 ± 2597.63 ng/mL·h, IV: 17,443.85 ± 2597.63ng/mL·h), terminal elimination half-life (t1/2) (PO: 7.26 ± 2.16h, IV: 4.78 ± 1.09h). TPB15, a promising candidate for treating TNBC, hasdemonstrated outstanding efficacy and safety in vitro and in vivo. This study established a simple, sensitive, and rapid HPLC-MS/MS bioanalytical method, developed and validated in accordance with FDA and EMA guidelines, for conducting pharmacokinetic and bioavailability studies of TPB15. The results revealed a favorable pharmacokinetic profile owing to its long t1/2. Nevertheless, the next phase of research should include formulation screening to enhance bioavailability, as well as clinical trials, metabolism pathway analysis, and assessment of potential drug-drug interactions.

Comprehensive phytochemical profiling of Phyllanthus emblica L. flowers on UHPLC/MS quadrupole time of flight, HPTLC, HPLC, and NMR analytical platforms reveals functional metabolites with potent anti-inflammatory effects in human (THP-1) macrophages.

Phyllanthus emblica L., renowned for its pharmacological benefits found in its fruits and leaves, has received considerable attention. However, there is a notable lack of research on its flowers, specifically on metabolite profiling and pharmacological activity. The present study aims to delineate the phytochemical constituents of hydromethanolic extract of P.emblica flowers by ultra-high-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UHPLC-QToF-MS), high-performance thin layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), infrared and nuclear magnetic resonance spectroscopic methods and subsequent evaluation of its anti-inflammatory potential. The identification and characterization of phytochemicals in P.emblica flowers was performed by UHPLC/MS-QToF in both positive and negative ionization modes. Additionally, marker compounds present in flower extract were analyzed using HPTLC, HPLC, FT-IR, and NMR methods. The anti-inflammatory potential was evaluated in lipopolysaccharide-stimulated THP-1 macrophages by evaluating inflammatory biomarkers. UHPLC/MS-QToF analysis facilitated the identification of 51 compounds from P.emblica flowers including gallic acid derivatives, flavonoid glycosides, and tannins based on their fragmentation patterns and previous literature reports. Notably, the study also identified spermidine compounds for the first time in this species. Optimization of HPTLC and HPLC methods marked the presence of corilagin as major compound followed by FT-IR and NMR spectral methods. Moreover, treatment with hydromethanolic extract of P.emblica flowers resulted in decreased levels of proinflammatory cytokines, TNF-α, IL-1β, and IL-6, alongside modulation of nuclear factor-κB activity in lipopolysaccharide-induced THP-1 macrophages. Chromatographic techniques in conjunction with spectral methods found robust prevalence in the identification of signature phytometabolites present in P. emblica flowers, which sets the basis for its anti-inflammatory potentials. The studies established a foundation for further exploration of potential applications of P. emblica flowers across various domains.

Challenges in Lipidomics Biomarker Identification: Avoiding the Pitfalls and Improving Reproducibility.

Identification of features with high levels of confidence in liquid chromatography-mass spectrometry (LC-MS) lipidomics research is an essential part of biomarker discovery, but existing software platforms can give inconsistent results, even from identical spectral data. This poses a clear challenge for reproducibility in biomarker identification. In this work, we illustrate the reproducibility gap for two open-access lipidomics platforms, MS DIAL and Lipostar, finding just 14.0% identification agreement when analyzing identical LC-MS spectra using default settings. Whilst the software platforms performed more consistently using fragmentation data, agreement was still only 36.1% for MS2 spectra. This highlights the critical importance of validation across positive and negative LC-MS modes, as well as the manual curation of spectra and lipidomics software outputs, in order to reduce identification errors caused by closely related lipids and co-elution issues. This curation process can be supplemented by data-driven outlier detection in assessing spectral outputs, which is demonstrated here using a novel machine learning approach based on support vector machine regression combined with leave-one-out cross-validation. These steps are essential to reduce the frequency of false positive identifications and close the reproducibility gap, including between software platforms, which, for downstream users such as bioinformaticians and clinicians, can be an underappreciated source of biomarker identification errors.

Chemical profile, antioxidant and anti-Alzheimer activity of leaves and flowers of Markhamia lutea cultivated in Egypt: in vitro and in silico studies

BackgroundNowadays Alzheimer’s disease and its treatment methods are global concerns. Patients with this disease have poor prognosis and need supportive treatment. The antioxidant activity, anti-acetylcholinesterase (anti-AChE), anti-butyryl cholinesterase (anti-BChE) and Aβ-amyloid-42 inhibition activities of the ethanolic extracts of both leaves and flowers (LEE and FEE) of Markhamia lutea were assessed. The antioxidant activity of LEE and FEE was evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate, oxygen radical absorbance capacity and ferrozine iron metal chelation assays. Additionally, their total flavonoids and total phenolics were determined. The phytochemicals of LEE were analysed using LC–MS/Q-TOF in both positive and negative modes. Also, molecular docking was done for phytochemicals identified in LEE.ResultLEE exhibited higher antioxidant and anti-Alzheimer activities in all techniques due to its high flavonoids content. LEE showed better activity than donepezil in case of anti-butyryl cholinesterase than both donepezil and rivastigmine in case of Aβ-amyloid-42 inhibition. A total of 62 compounds were tentatively identified using Ultra-performance Liquid Chromatography-Electrospray Ionization-Quadrupole Time-of-Flight Mass Spectrometry (UHPLC–ESI–TOF–MS), viz. 35 flavonoids, 11 phenolic acids, 2 terpenoids, 2 phenylpropanoids derivatives, 7 polyphenols, 3 coumarins and 2 organic acids. The molecular docking of some constituents showed that isorhamnetin-O-rutinoside, sissotrin, 3,5,7-trihydroxy-4'-methoxyflavone (diosmetin), rosmarinic acid, kaempferol hexoside, kampferol-7-neohesperoside, acacetin, taxifolin and apigenin-O-hexoside exert a promising activity as anti-Alzheimer drugs.ConclusionThe LEE of Markhamia lutea contains secondary metabolites that is promising to act as natural antioxidants, acetylcholinesterase, butyryl cholinesterase and Aβ-amyloid-42 inhibition inhibitors, which can aid in the treatment of Alzheimer’s.Graphical

A Multimodal System for Lipid A Structural Analysis from a Single Colony.

Structural elucidation of Gram-negative bacterial lipid A traditionally requires chemical extraction followed by tandem MS data in the negative ion mode. Previously, we reported FLAT and FLATn as methods to rapidly determine the structure of lipid A without chromatographic techniques. In this work, we extend the capability and effectiveness of these techniques to elucidate the chemical structure in a de novo manner by including the use of positive ion mode (FLAT+ and FLATn+) spectral approaches. Advantages of positive mode analysis of lipid A include the generation of more interpretable and informative fragmentation patterns that include the identification of diagnostic fragments, including selective dissociation of a glycosidic bond between two glucosamine units and the selective dissociation at the secondary acyl chain in 2'-N, allowing for the determination of the composition of fatty acids. As a proof of principle, we present here two previously uncharacterized structures of lipid A from Roseomonas mucosa (R. mucosa) and Moraxella canis (M. canis). In R. mucosa, we determined the lipid A structure with a nonconventional backbone of-β-1,6 linked 2,3-dideoxy-2,3-diamno-d-glucopyranose further modified with galacturonic acid in the place of typical 1-phosphate, and in M. canis, we assigned a single discrete structure using the specific fragmentation patterns of terminal phosphate groups present in lipid A. Therefore, FLATn+, in combination with FLAT and FLATn, provides a multimodal structural platform for rapid structure characterization of unusual and complex lipid A structures from a single colony.

Impact of the internal modes on the sphaleron decay

We study the sphaleron solutions in two deformations of the ϕ6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\phi ^6$$\\end{document} model and analyze the oscillons originated from them. We find that the presence of internal modes plays a crucial role in the sphaleron collapse. The positive internal modes triggered by a squeezing of the sphaleron are able to change the direction of collapse. We provide an analytical understanding behind this phenomenon.

Tandem MS Elucidation of the Late-Stage Degradation Mechanism of Nitroplasticizer.

Understanding the degradation behavior of nitroplasticizer (NP) and the subsequent production of nitro-organics is crucial for both environmental monitoring and material development. A nontargeted approach via LC-QTOF-MS was employed to thoroughly study the degradation mechanism of NP in its late aging stage. Both positive and negative modes of ESI were performed to increase the compound coverage. To shed light on the fragmentation behavior of NP degradants (e.g., compounds containing a high density of NO2 moieties and oxygen sites) in the positive mode, which is rarely reported, the high-resolution tandem MS information on precursor ions at m/z 251(+), 254(+), 266(+), and 270(+) and a pair of isomeric ions at m/z 284(+) was investigated to extract their common diagnostic ions and dissociation channels, including the neutral loss of 2,2-dinitropropanol, nitro-nitrite rearrangement, homolytic cleavage of NO2, and simple inductive cleavage. Additionally, leveraging the sensitivity for nitroaromatics in the negative polarity, negative ions m/z 182(-) and 233(-) are identified as dinitroaniline and dinitronaphthol, respectively, which confirm the secondary hydrolysis pathway of the antioxidant (e.g., N-phenyl-2-naphthylamine) postulated in our previous work. In addition to earlier findings, the detection of these eight degradants further supports the evidence of increased acid concentration and aging temperatures in the late-stage NP environment, which contribute to intricate degradation behaviors in different aging environments.

Quantitative determination of liposomal irinotecan and SN-38 concentrations in plasma samples from children with solid tumors: Use of a cryoprotectant solution to enhance liposome stability

Preclinical studies have demonstrated that liposomal irinotecan (CPT-11), a topoisomerase I inhibitor, has broad activity against adult cancers, including pancreatic, gastric, colon, lung, glioma, ovarian, and breast cancer. Encapsulation of irinotecan into liposomes can modify its pharmacokinetic properties dramatically. Also, the pharmacokinetic profiles of liposomal drug formulations are not fully understood; thus, bioanalytical methods are needed to separate and quantify nonencapsulated vs. encapsulated concentrations. In this study, two robust, specific, and sensitive LC-MS/MS methods were developed and validated to separate and quantify the nonencapsulated CPT-11 (NE-CPT-11) from the sum-total CPT-11 (T-CPT-11) and its major metabolite, SN-38, in human plasma after intravenous administration of liposomal irinotecan. NE-CPT-11 and SN-38 were separated from plasma samples by using solid-phase extraction, and T-CPT-11 was measured by protein precipitation. The liposomal CPT-11 formulation was unstable during sample storage and handling, resulting in elevated NE-CPT-11 concentration. To improve the stability of liposomal CPT-11, a cryoprotectant solution was added to human plasma samples prior to storage and processing. CPT-11, SN-38, and their respective internal standards, CPT-11-d10 and SN-38-d3, were chromatographically separated on a reversed-phase C18 analytical column. The drugs were detected on a triple quadrupole mass spectrometer in the positive MRM ion mode by monitoring the transitions 587.3 > 124.1 (CPT-11) and 393.0 > 349.1 (SN-38). The calibration curves demonstrated a good fit across the concentration ranges of 10–5000 ng/mL for T-CPT-11, 2.5–250 ng/mL for NE-CPT-11, and 1–500 ng/mL for SN-38. The accuracy and precision were within the acceptable limits, matrix effects were nonsignificant, recoveries were consistent and reproducible, and the analytes were stable under all tested storage conditions. Finally, the LC-MS/MS methods were successfully applied in a phase I clinical pharmacokinetic study of nanoliposomal irinotecan (Onivyde®) in pediatric patients with recurrent solid malignancies or Ewing sarcoma.

An untargeted comparative metabolomics analysis of infants with and without late-onset breast milk jaundice.

Late-onset breast milk jaundice (LBMJ) is a common form of hyperbilirubinemia, which can result in serious complications for newborns with persistently high bilirubin levels. The aim of this study was to investigate the differences in fecal metabolites between breastfed infants with and without LBMJ in order to elucidate potential biological mechanisms. Biological samples were collected from 12 infants with LBMJ and 12 healthy individuals. Ultra-high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS) was utilized for non-targeted determination of fecal metabolites. Principal components analysis (PCA), cluster analysis, and differential metabolite analysis were performed in both positive ion mode and negative ion mode for the two groups. Additionally, the KEGG database was employed to comprehensively analyze the pathways of differential metabolites. There were no significant differences in maternal and neonatal demographic characteristics between the two groups (p > 0.05). The results of PCA and cluster heat map analysis in both modes showed that there were significant differences in metabolites between the two groups. Among 751 differential metabolites (DMs) detected in positive ion mode, 720 were up-regulated in the case group while 31 were down-regulated. In negative ion mode, 1891 DMs were detected, including 817 up-regulated metabolites and 1074 down-regulated metabolites in the case group. Analysis of differential metabolic pathways showed that the DMs of the two groups were mainly annotated and enriched in Biotin metabolism, N-Glycan biosynthesis, Taurine and hypotaurine metabolism, Pyrimidine metabolism, and Pentose and glucuronate interconversions. Significant differences exist in fecal metabolites between LBMJ infants and healthy controls. The study of differential metabolic pathways provides insights into the mechanism of LBMJ.

Ether-Diol Ambiguity: An Inconspicuous Issue in the Structure Elucidation of Oxygenated Natural Products.

Tertiary and allylic hydroxyl groups readily eliminate water during positive ion mode mass spectrometry and may show similar NMR spectra to their corresponding ethers. In a routine structure elucidation workflow, these factors can cause researchers to incorrectly assign diol moieties as ethers or vice versa, leading to inaccurate chemical structures. After facing this problem during our work on oxygenated sesquiterpenoids from a Fusarium sp. fungal strain, we became aware of this challenging issue. We examined the literature for oxygenated natural products bearing these functional groups, and with the aid of density functional calculations of NMR chemical shifts, we now report the structures of 15 natural products that should be revised. We further establish that derivatizing sub-micromolar amounts of alcohols to their sulfates can be used to distinguish these from their corresponding ethers using liquid chromatography negative ion mode mass spectrometry. Finally, we isolated lignoren/cyclonerodiol from the Fusarium sp. culture extract and supported its revised identity as cyclonerodiol using this sulfation approach. Our results suggest that ether-diol ambiguity could be a prevalent issue affecting the structure elucidation of oxygenated natural products and highlight the importance of using complementary techniques, such as sulfation with LC-(-)-ESI-MS or density functional calculations of NMR chemical shifts.

Thunbergia's Flowers Secondary Metabolites a Natural Armor Against Kidney Damage by Diclofenac.

Nephrotoxicity is a common side effect arising from exposure to drugs or toxins. The study investigates the therapeutic effects of Thunbergia alata and Thunbergia erecta flowers on diclofenac-induced renal injury. Secondary metabolite characterization by positive mode high-resolution-ESI (LC-HR-ESI-MS) was followed by assessing their renal protection against diclofenac-induced damage and molecular docking studies. Using positive LC-HR-ESI-MS, 18 compounds from T. erecta and T. alata were identified. Diclofenac administration induced significant deterioration of all parameters in the kidney in addition to renal tissue contents of several inflammatory markers. The flower extracts of T. alata and T. erecta showed a clear improvement in the treated groups compared to the diclofenac-control group. The results were confirmed by histopathological examinations followed by immunohistochemical determination of vascular endothelial growth factor (VEGF), nuclear factor erythroid 2-related factor 2 (Nrf2), and transforming growth factor beta 1 (TGF-β1) expression. Furthermore, a protein-protein network to understand the complex interplay between the target proteins and their counterparts was done in addition to a molecular docking study of the de-replicated compounds in the active sites of NF-κB, TGF-β1, and VEGFR.

Comprehensive Characterization of Porous Transport Electrodes with SEM, XPS, and Tof-SIMS

Advancements towards more efficient design and manufacturability of polymer electrolyte membrane electrolyzers include recent efforts to better integrate the porous transport layer (PTL) and adjacent anodic catalyst layer (CL), forming the porous transport electrode (PTE). It is well known that characterizations of the PTL alone, especially when combined with a protective coating, present numerous challenges. The PTE structure is even more complex, and it is difficult to comprehensively characterize all components and interfaces. In prior work, we established Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) as a characterization technique for the PTLs coated with protective coatings. This work demonstrates ToF-SIMS as a powerful technique for the characterization of PTLs integrated with CLs. A series of sintered Ti PTLs were first coated with protective Pt coatings and then coated with various IrOx and IrRuOx catalysts via electrodeposition. Prepared PTE samples ranged in catalyst loadings and catalyst composition. Selected samples were also subjected to annealing post-treatments to further modify catalyst composition. X-ray photoelectron spectroscopy (XPS) was conducted to identify surface chemical speciation and states of the catalysts. ToF-SIMS analysis was conducted using Cs in both positive and negative modes to identify chemical species, including Ir, Ru, and their oxides as a function of catalyst layer depth. These two methods were complemented by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy (SEM- EDS) analysis to evaluate morphology and distribution of catalysts. This comprehensive physical and chemical characterization of the PTEs provides insights that are useful for the characterization of as produced, modified, and degraded PTE samples.

Determination of Choline-Containing Compounds in Rice Bran Fermented with Aspergillus oryzae Using Liquid Chromatography/Tandem Mass Spectrometry.

Choline-containing compounds are essential nutrients for human activity, as they are involved in many biological processes, including cell membrane organization, methyl group donation, neurotransmission, signal transduction, lipid transport, and metabolism. These compounds are normally obtained from food. Fermented brown rice and rice bran with Aspergillus oryzae (FBRA) is a fermented food product derived from rice and rice ingredients. FBRA exhibits a multitude of functional properties with respect to the health sciences. This study has a particular focus on choline-containing compounds. We first developed a simultaneous liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis method for seven choline-containing compounds. The method was subsequently applied to FBRA and its ingredients. Hydrophilic interaction chromatography (HILIC) and selected reaction monitoring were employed for the simultaneous analysis of seven choline-containing compounds. MS ion source conditions were optimized in positive ion mode, and the product ions derived from the choline group were obtained through MS/MS optimization. Under optimized HILIC conditions, the peaks exhibited good shape without peak tailing. Calibration curves demonstrated high linearity across a 300- to 10,000-fold concentration range. The application of the method to FBRA and other ingredients revealed significant differences between food with and without fermentation. In particular, betaine and α-glycerophosphocholine were found to be highest in FBRA and brown rice malt, respectively. The results indicated that the fermentation processing of rice ingredients results in alterations to the choline-containing compounds present in foods. The developed HILIC/MS/MS method proved to be a valuable tool for elucidating the composition of choline-containing compounds in foods.

Identification of Fatty Acids, Amides and Cinnamic Acid Derivatives in Supercritical-CO2 Extracts of Cinnamomum tamala Leaves Using UPLC-Q-TOF-MSE Combined with Chemometrics.

Cinnamomum tamala leaf (CTL), also known as Indian bay leaf, is used all over the world for seasoning, flavoring, and medicinal purposes. These characteristics could be explained by the presence of several essential bioactive substances and lipid derivatives. In this work, rapid screening and identification of the chemical compounds in supercritical (SC)-CO2 extracts of CTL by use of UPLC-Q-TOF-MSE with a multivariate statistical analysis approach was established in both negative and positive mode. A total of 166 metabolites, including 66 monocarboxylic fatty acids, 52 dicarboxylic fatty acids, 27 fatty acid amides, and 21 cinnamic acid derivatives, were tentatively identified based on accurate mass and the mass spectrometric fragmentation pattern, out of which 142 compounds were common in all SC-CO2 extracts of CTL. Further, PCA and cluster hierarchical analysis clearly discriminated the chemical profile of analyzed extracts and allowed the selection of SC-CO2 extract rich in fatty acids, fatty acid amides, and other bioactive constituents. The result showed that the higher number of compounds was detected in CTL4 (300 bar/55 °C) extract than the other CTL extracts. The mono- and di-carboxylic fatty acids, fatty acid amides, and cinnamic acid derivatives were identified in CTL for the first time. UPLC-Q-TOF-MSE combined with chemometric analysis is a powerful method to rapidly screen the metabolite profiling to justify the quality of CTL as a flavoring agent and in functional foods.