Liquid Chromatography-electrospray Mass Spectrometry Research Articles

Identification and Analysis of Phenolic Compounds in Vaccinium uliginosum L. and Its Lipid-Lowering Activity In Vitro.

Vaccinium uliginosum L. (VU), rich in polyphenols, is an important wild berry resource primarily distributed in extremely cold regions. However, the detailed composition of Vaccinium uliginosum L. polyphenols (VUPs) has not been reported, which limits the development and utilization of VU. In this study, VU-free polyphenols (VUFPs) and VU-bound polyphenols (VUBPs) were, respectively, extracted using an ultrasonic, complex enzyme and alkali extraction method; the compositions were identified using ultra-performance liquid chromatography-electrospray ionization mass spectrometry, and lipid-lowering activity in vitro was evaluated. The results showed that 885 polyphenols and 47 anthocyanins were detected in the VUFPs and VUBPs, and 30 anthocyanin monomers were firstly detected in VU. Compared with the model group, the accumulation of lipid droplets and the total cholesterol and triglyceride contents in the high-concentration VUP group reduced by 36.95%, 65.82%, and 62.43%, respectively, and liver damage was also alleviated. It was also found that VUP can regulate the level of Asialoglycoprotein receptor 1, a new target for lipid lowering. In summary, this study provides a detailed report on VUP for the first time, confirming that VUP has lipid-lowering potential in vitro. These findings suggest new strategies and theoretical support for the development and utilization of VU, especially in the field of functional foods.

LC-ESI-MS and GC-MS Profiling, Chemical Composition, and Cytotoxic Activity of Endophytic Fungus Pleosporales sp. Derived from Artemisia annua

The chemical profiling of ethyl acetate extract of the endophytic fungus Pleosporales sp. using liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) revealed the presence of 12 metabolites of different chemical classes such as steroids, α-pyrones, asterric acid derivatives, and quinones. Additionally, the gas chromatography–mass spectrometry (GC-MS) profiling of the ethyl acetate (EtOAc) and methanol extracts exhibited the presence of fatty acids and their esters, in which methyl palmitate (18.72%, and 25.48%, respectively) and methyl linoleate (11.92% and 23.39%, respectively) were found in both extracts. On the other hand, palmitic acid (12.60%), methyl oleate (26.90%), oleic acid (4.01%) and linoleic acid (3.25%) were present only in methanol extract. Furthermore, ethyl palmitate (12.60%), 13-octadecenoic acid (19.36%), and ethyl linoleate (3.25%) occurred in EtOAc extract. A phytochemical investigation of both extracts led to the isolation of fatty acids such as palmitic acid (18), oleic acid (20), and linoleic acid (21) and their esters including methyl palmitate (13), methyl stearate (22), methyl linoleate (16), methyl 3-hydroxy-5-methylhexanoate (23), and monomethyl azelate (27), in addition to monoacyl derivatives of glycerol such as 3,3-dihydroxypropyl hexadecanoate (24), 2,3-dihydroxypropyl elaidate (25), and 1-linoleoyl-sn-glycerol (26). The structures of the isolated compounds were identified by different spectroscopic analyses including 1H- and 13C-NMR and GC-MS. The EtOAc extract exhibited a cytotoxic effect against MCF-7 and HepG-2 cell lines, with IC50 values of 4.12 ± 0.10 and 10.05 ± 0.05 μg/mL, respectively.

PHYTOCHEMICAL PROFILING BY LC-ESI-MS/MS AND DETERMINATION OF ANTIOXIDANT, ANTI-ALZHEIMER AND ANTITYROSINASE ACTIVITIES OF TWO ASPARAGACEAE SPECIES: Scilla hyacinthoides L. AND Scilla ingridiae SPETA

In this study, in vitro antioxidant, antialzheimer and antityrosinase activity, total phenolic and flavonoid components, chemical profiling, identified by LC-ESI-MS/MS analysis and also chemometric analysis, of two different parts of Scilla species (Scilla hyacinthoides L. and Scilla ingridiae Speta) were determined in detailed perspective. The highest contents of total phenolics and total flavonoids were determined in S1TU (S. hyacinthoides aerial parts) extract (11.72 µg GAE/mg) and S2TU (S. ingridiae aerial parts) extract (31.53 µg QE/mg). The highest ABTS and CUPRAC activities were found in S1TU and S2TU extracts. The inhibitory activities of the extracts on the enzyme acetylcholinesterase were investigated. S1TU and S2TU extracts again showed the highest activity. Although the antirosinase enzyme inhibitory activities of the extracts were generally similar and high, the S2TA extract (S.ingridiae corm parts) showed the highest activity. Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) was used to determine the content of phenolic components of the extracts. Fourteen different bioactive components were determined in the analyzes and their amounts were measured. The data obtained were analyzed chemometrically such as pricipal component analysis (PCA),hierarchical comoponent analysis (HCA) and their relationships to each other were supported visually and numerically with Pearson correlation graphs, heat maps, etc. The research results have shown that the various components of the plant have a good effect on various biological activities, so that it can be used for various purposes in the future (especially with a good degree of antityrosinase activity), taking into account the results. The biological activities demonstrated here can rationalize the use of the plant in traditional medicine.

Systematic Characterization of the Oligosaccharide Profile of Human Milk in Rural Areas of Central China: Quantitative Tracking of Human Milk Oligosaccharide Composition during 12 Months of Lactation.

This study investigates changes in human milk oligosaccharide (HMO) composition over a 12 month breastfeeding period in rural central China. The HMO profiles of 97 mothers were analyzed by graphitized carbon liquid chromatography-electrospray ionization-mass spectrometry. This method was simple to prepare samples and can simultaneously and absolutely quantify at least 20 neutral and acidic HMOs. All mothers were classified into four milk groups based on the presence or absence of specific α-1,2 and α-1,4-fucosylated HMOs. The main oligosaccharides in milk groups I and II were 2'-FL, LDFT, LNFP-I, and LNDFH-I, while LNT, 3-FL, LNFP-II, LNFP-V, LNDFH-II, and DFLNH-b were predominant in milk groups III and IV. Additionally, the lactation period was the primary factor affecting the concentration of individual HMOs. The concentrations of most HMOs decreased with lactation and stabilized after 180 days. However, the concentrations of 3-FL, LDFT, and LNDFH II increased gradually over the lactation period, and the concentration of 3'-SL decreased during early lactation (5-180 days) but increased during later lactation (180-365 days). Furthermore, Spearman correlation analysis revealed that maternal factors and infant factors may also affect the concentration of various HMOs. These findings provide fundamental insights for the development of a comprehensive human milk database.

Betaine and B12 Intake, Glutathione Concentration, and MTHFR, PEMT, and MTHFD1 Genotypes Are Associated with Diabetes-Related Parameters in Polish Adults

BackgroundThere is a growing body of evidence on associations between one-carbon metabolism (OCM) and diabetes-related parameters. For this reason, we aimed to examine the associations of plasma choline, betaine, trimethylamine N-oxide (TMAO), glutathione (GSH), serum folate, vitamin B12, dihydrofolate reductase (rs70991108) genotype, methylenetetrahydrofolate reductase (MTHFR) (rs180113) genotype, methylenetetrahydrofolate dehydrogenase (MTHFD1) (rs2236225) genotype, and phosphatidylethanolamine N-methyltransferase (rs7946 and rs12325817) genotype with fasting glucose level, insulin level, and diabetes-related indices. MethodsThe study group consisted of 421 Polish adults aged 20–40 y. Food intake was assessed using a 3-d food diary. Plasma concentrations of choline, betaine, and TMAO were determined by ultra-high-performance liquid chromatography-electrospray ionization mass spectrometry. The total plasma GSH level was measured by high-performance liquid chromatography. Insulin, folate, and vitamin B12 concentrations were estimated by enzyme-linked immunosorbent assay method. Genotyping was performed with TaqMan probes. ResultsGSH level was negatively associated with insulin (β = −0.11, P < 0.05) and gamma-glutamyl transferase (GGTP) (β = −0.12, P < 0.05), and positively associated with fasting glucose (β = 0.11, P < 0.05). Betaine intake was negatively associated with serum insulin concentration (β = −0.13, P < 0.05) and HOMA-IR (β = −0.12, P < 0.05). Choline intake was negatively associated with insulin (β = −0.17, P < 0.01). Serum folate level was negatively associated with GGTP (β = −0.11; P < 0.05). The methylenetetrahydrofolate reductase (MTHFR) CC genotype was associated with higher serum insulin levels (β = 0.15; P < 0.01) and higher HOMA-IR (β = 0.15, P < 0.01), whereas the MTHFD1 AA genotype was negatively associated with Quantitative Insulin Sensitivity Check Index (β = −0.11, P < 0.05). ConclusionsOur findings suggest that higher GSHL and higher intake of betaine, B12, and choline, as well as the TT genotype of MTHFR and the AA genotype of MTHFD1, are associated with lower diabetes-related parameters among adults.

Nutritional status and extended metabolic screening in Egyptian children with uncomplicated type 1 diabetes

Nutritional status assessment, including amino acids, carnitine, and acylcarnitine profile, is an important component of diabetes care management, influencing growth and metabolic regulation. A designed case–control research included 100 Egyptian participants (50 T1DM and 50 healthy controls) aged 6 to 18 years old. The participants' nutritional status was assessed using the Body Mass Index (BMI) Z-score. Extended metabolic screening (EMS) was performed using a high-performance liquid chromatography-electrospray ionization-mass spectroscopy system to evaluate the levels of 14 amino acids, free carnitine, and 27 carnitine esters. T1DM children had considerably lower anthropometric Z-scores than the control group, with 16% undernutrition and 32% short stature. Total aromatic amino acids, phenylalanine, phenylalanine/tyrosine ratio, proline, arginine, leucine, isoleucine, free carnitine, and carnitine esters levels were considerably lower in the diabetic group, suggesting an altered amino acid and carnitine metabolism in type 1 diabetes. BMI Z-score showed a significant positive correlation with Leucine, Isoleucine, Phenylalanine, Citrulline, Tyrosine, Arginine, Proline, free carnitine, and some carnitine esters (Acetylcarnitine, Hydroxy-Isovalerylcarnitine, Hexanoylcarnitine, Methylglutarylcarnitine, Dodecanoylcarnitine, Tetradecanoylcarnitine, and Hexadecanoylcarnitine). HbA1c% had a significant negative correlation with Total aromatic amino acids, Branched-chain amino acid/Total aromatic amino acids ratio, Glutamic Acid, Citrulline, Tyrosine, Arginine, Proline, and certain carnitine esters (Propionylcarnitine, Methylglutarylcarnitine, Decanoylcarnitine, Octadecanoylcarnitine and Octadecenoylcarnitine), suggest that dysregulated amino acid and carnitine metabolism may be negatively affect the glycaemic control in children with TIDM. In conclusion, regular nutritional assessments including EMS of T1DM patients are critical in terms of diet quality and protein content for improved growth and glycemic management.

PM10 Organic Aerosol Fingerprints by Using Liquid Chromatography Orbitrap Mass Spectrometry: Urban vs. Suburban in an Eastern Mediterranean Medium-Sized Coastal City

This study compares the PM10 (particulate matter of diameter smaller than 10 μm) organic aerosol composition between urban and suburban stations in Heraklion, Crete, during winter 2024 in order to highlight the impact of local anthropogenic activities on urban atmospheric particulate matter pollution. Using an HPLC-ESI-MS Orbitrap analyzer (High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry) in full MS scan mode at a resolution of 140,000, 48 daily aerosol filter extracts were analyzed in both positive and negative modes, resulting in the detection of 2809 and 3823 features, respectively. Features with at least five times higher intensity in the urban environment compared to the suburban, and p &lt; 0.05, were deemed significant. A correlation with black carbon (r &gt; 0.6) was observed for 71% of significant urban features in positive mode. These features showed a predominance of low O:C ratios (&lt;0.2) and the majority were classified as intermediate volatility organic compounds (IVOCs), indicating fresh primary emissions. A clear urban–suburban distinction was shown by PCA of positive mode features, unlike the negative mode features. Regarding the total intensity of the features, urban samples were on average 55% higher than suburban samples in positive mode and 39% higher in negative mode. This study reveals the molecular profile of locally emitted combustion related organics observed in positive mode in an urban environment.

Diospyros kaki fruit extract produces antiarthritic and antinociceptive effects in rats with complete Freund's adjuvant-induced arthritis.

Current treatments for rheumatoid arthritis produce untoward effects; thus, considerable effort has been made to recognize effective herbal medicines against the condition. In the present study, the therapeutic effect of Diospyros kaki fruit hydroalcoholic extract (DFHE) on complete Freund's adjuvant (CFA)-induced arthritis in rats was investigated. The extract was characterized using liquid chromatography-electrospray mass spectrometry (LC-ESIMS). Male Wistar rats were grouped as follows (eight rats in each): control, CFA, CFA + indomethacin (5 mg/kg), CFA + DFHE (50 mg/kg), and CFA + DFHE (100 mg/kg). Paw volume, mechanical allodynia, thermal hyperalgesia, and arthritis score were evaluated. Serum levels of malondialdehyde (MDA), thiol groups, tumor necrosis factor-alpha (TNF-α), as well as glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were evaluated. Carotenoids were found to be the major components of DFHE. Administration of DFHE (100 mg/kg) significantly decreased arthritis score, paw volume, and thermal hyperalgesia, and improved mechanical allodynia. MDA and TNF-α levels were decreased while thiol levels and SOD and GPx activities were increased in DFHE-treated groups compared to the CFA group. These results suggest that D. kaki extract caused an improvement in clinical signs of rheumatoid arthritis symptoms possibly through suppression of oxidative stress and inflammation.

Gallic Acid Enhances the Efficacy of BCR::ABL1 Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia through Inhibition of Mitochondrial Respiration and Modulation of Oncogenic Signaling Pathways.

While BCR::ABL1 tyrosine kinase inhibitors have transformed the treatment paradigm for chronic myeloid leukemia (CML), disease progression and treatment resistance due to BCR::ABL1-dependent and BCR::ABL1-independent mechanisms remain a therapeutic challenge. Natural compounds derived from plants have significantly contributed to cancer pharmacotherapy. This study investigated the efficacy of an active component of Leea indica, a local medicinal plant, in CML. Using high-performance liquid chromatography-electrospray ionization-mass spectrometry, a chemical constituent from L. indica extract was isolated and identified as gallic acid. Commercially obtained gallic acid was used as a chemical standard. Gallic acid from L. indica inhibited proliferation and induced apoptosis in CML cell lines, as did the chemical standard. Furthermore, gallic acid induced apoptosis and decreased the colony formation of primary CML CD34+ cells. The combination of isolated gallic acid or its chemical standard with BCR::ABL1 tyrosine kinase inhibitors resulted in a significantly greater inhibition of colony formation and cell growth compared to a single drug alone. Mechanistically, CML cells treated with gallic acid exhibited the disruption of multiple oncogenic pathways including ERK/MAPK, FLT3 and JAK/STAT, as well as impaired mitochondrial respiration. Rescue studies showed that gallic acid is significantly less effective in inducing apoptosis in mitochondrial respiration-deficient ρ0 cells compared to wildtype cells, suggesting that the action of gallic acid is largely through the inhibition of mitochondrial respiration. Our findings highlight the therapeutic potential of L. indica in CML and suggest that gallic acid may be a promising lead chemical constituent for further development for CML treatment.

Comparative Analysis of Serum Amino Acid Profiles in Patients with Myasthenia Gravis and Multiple Sclerosis.

Background: Multiple sclerosis (MS) and myasthenia gravis (MG) are autoimmune diseases that attack the central nervous system (CNS) and the neuromuscular junction, respectively. As the common pathogenesis of both diseases is associated with an autoimmune background and the involvement of T and B lymphocytes, the overlapping of selected clinical symptoms may cause difficulties in the differential diagnosis of both diseases. Methods: The aim of the study was to use Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS/MS) in conjunction with multivariate statistical analyses to examine the changes in amino acid metabolic profiles between patients with MG, MS, and a control group. Results: Comparative analysis of amino acids (AA) between patients with MG, MS, and within the control group allowed for the identification of statistically significant differences in the amino acid profile. Comparing the patients (patients with MS and MG) with the control group, and after taking the results of multiple tests into account, it was observed that amino acids such as ARG, PRO, TRP, CIT were significantly different between the groups. When considering the comparison between the AA concentrations in MS and MG patients, we found three AAs that were significantly different in the MS and MG groups, after correcting for multiple testing (CIT, GABA, and AAA). Higher concentrations of amino acids that showed significant differences were observed in patients with myasthenia gravis. Conclusions: Our results have indicated AAs that may prove valuable for improving the diagnostics of MS and MG patients. To better assess the potential utility of these markers, their performance requires further validation in a larger study group and limitation of possible confounding factors, e.g., medications and diet.

Spatial distribution of differential metabolites in different parts of Tetrastigma hemsleyanum Diels et Gilg by ultrahigh-performance liquid chromatography/mass spectrometry and desorption electrospray ionization mass spectrometry imaging

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a homology medicine and food that is rich in bioactive ingredients such as flavonoids and phenolic acids. A strategy that integrates ultrahigh-performance liquid chromatography–electrospray ionization mass spectrometry (UHPLC–ESI/MS) and desorption electrospray ionization mass spectrometry imaging (DESI-MSI) spatial metabolomics analysis was proposed and applied to different parts of T. hemsleyanum for the first time. A total of 132 compounds were tentatively identified, and 3, 7, and 24 components were found only in tuberous roots (TRs), fibrous roots (FRs), and leaves, respectively, using UHPLC–ESI/MS. The DESI-MSI results showed that the spatial distribution of flavonoids between the aerial and underground parts was diverse; for example, vitexin-2″-O-glucoside was largely localized in the epidermis and xylem of TRs, while a small amount was restricted to the xylem of the leaf margin and FRs. There was a higher abundance of most organic acids and flavonoids in the leaves than in the underground parts. Some flavonoids showed the same abundance in FRs and TRs, but the levels of most compounds were considerably higher in FRs. It is possible for leaves and FRs to become new medicinal parts of T. hemsleyanum. Through chemometrics statistics analysis, 19 key differential compounds in different parts of T. hemsleyanum were found, and the pharmacological mechanisms of the main differential metabolites were predicted by network pharmacology. This study provides a novel method for the medicinal development of T. hemsleyanum, showing its great potential in the development of medicinal resources.

Neutrophil Depletion Changes the N-Glycosylation Pattern of IgG in Experimental Murine Sepsis.

Sepsis is a life-threatening condition with a rising disease burden worldwide. It is a multifactorial disease and is defined as a dysregulated host response to infection. Neutrophils have been shown to be involved in the pathogenesis of sepsis by exacerbating inflammation. However, the exact effector mechanism of action still remains a mystery. Changes in the glycosylation pattern of the immunoglobulin G (IgG) Fc region are described for several diseases including meningococcal sepsis. In this study, we investigated the possible contribution of neutrophils and neutrophil implication, potentially related to degranulation or neutrophil extracellular trap (NET) formation in changing the IgG Fc N-glycosylation pattern in a murine sepsis model. We have measured the serum level of cytokines/chemokines and immunoglobulins, the serum activity of neutrophil elastase (NE), and analyzed the IgG Fc glycosylation pattern by Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS) and Lectin enzyme-linked immunosorbent assay (ELISA). We observed an increased activity of NE- and neutrophil-associated cytokines such as keratinocyte chemoattractant (KC) with the development of sepsis. Regarding the IgG Fc N-glycosylation, we observed an increase in fucosylation and α1,3-galactosylation and a decrease for sialyation. Interestingly, these changes were not uniform for all IgG subclasses. After depletion of neutrophils, we saw a change in the exposure of fucose and α2,6-linked sialic acid during the time course of our experimental sepsis model. In conclusion, neutrophils can influence changes in the IgG glycosylation pattern in experimental sepsis.

Chemical Composition, Nutritional, and Biological Properties of Extracts Obtained with Different Techniques from Aronia melanocarpa Berries.

This study investigates the chemical composition, nutritional, and biological properties of extracts obtained from A. melanocarpa berries using different extraction methods and solvents. Hydrodistillation and supercritical fluid extraction with CO2 allowed us to isolate fruit essential oil (HDEX) and fixed oil (SFEEX), respectively. A phenol-enriched extract was obtained using a mild ultrasound-assisted maceration with methanol (UAMM). The HDEX most abundant component, using gas chromatography-mass spectrometry (GC/MS), was italicene epoxide (17.2%), followed by hexadecanoic acid (12.4%), khusinol (10.5%), limonene (9.7%), dodecanoic acid (9.7%), and (E)-anethole (6.1%). Linoleic (348.9 mg/g of extract, 70.5%), oleic (88.9 mg/g, 17.9%), and palmitic (40.8 mg/g, 8.2%) acids, followed by α-linolenic and stearic acids, were the main fatty acids in SFEEX determined using high-performance liquid chromatography coupled with a photodiode array detector and an evaporative light scattering detector (HPLC-DAD/ELSD). HPLC-DAD analyses of SFEEX identified β-carotene as the main carotenoid (1.7 mg/g), while HPLC with fluorescence detection (FLU) evidenced α-tocopherol (1.2 mg/g) as the most abundant tocopherol isoform in SFEEX. Liquid chromatography-electrospray ionization-MS (LC-ESI-MS) analysis of UAMM showed the presence of quercetin-sulfate (15.6%, major component), malvidin 3-O-(6-O-p-coumaroyl) glucoside-4-vinylphenol adduct (pigment B) (9.3%), di-caffeoyl coumaroyl spermidine (7.6%), methyl-epigallocatechin (5.68%), and phloretin (4.1%), while flavonoids (70.5%) and phenolic acids (23.9%) emerged as the most abundant polyphenol classes. UAMM exerted a complete inhibition of the cholesterol oxidative degradation at 140 °C from 75 μg of extract, showing 50% protection at 30.6 μg (IA50). Furthermore, UAMM significantly reduced viability (31-48%) in A375 melanoma cells in the range of 500-2000 μg/mL after 96 h of incubation (MTT assay), with a low toxic effect in normal HaCaT keratinocytes. The results of this research extend the knowledge of the nutritional and biological properties of A. melanocarpa berries, providing useful information on specific extracts for potential food, cosmetic, and pharmaceutical applications.

LC and LC-MS/MS Studies for the Separation and Identification of Impurities and Degradation Products of Betaxolol.

Betaxolol (Bx) is a selective β1 receptor blocker used in the treatment of hypertension and glaucoma. The aim of the present work was to demonstrate an approach involving use of liquid chromatography (LC) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) for the simultaneous separation, identification and characterization of impurities and of degradation products of betaxolol without their isolation from the reaction mixtures. At optimum condition, and according to ICH guidelines, the limit of detection (LOD) and limit of quantification (LOQ) for Bx are found to be 5.46 and 16.54μgmL-1, respectively. However, the LOD and LOQ for the major degradation product P6 were 2.15 and 6.53μgmL-1. Betaxolol was subjected to hydrolytic (acidic and basic) and oxidative, stress conditions according to International Conference on Harmonization (ICH) guideline Q1A (R2), and as results, the drug was found to be labile in acidic, basic and oxidative stress conditions. Based on LC-ESI/MS analysis, the found results revealed that Bx decomposes in acidic, basic and oxidizing environments. All degradation products were identified with the help of their fragmentation pattern and the masses obtained upon the MS analysis.

Ion-pair chromatographic attribute in the retention of ammonium ion on a crown ether-based and a polysaccharide-based chiral stationary phases. Some mobile phase additives compatible with liquid chromatography-electrospray ionization-mass spectrometry

The design of the mobile phase additive useful in HPLC analysis on two types of chiral stationary phases, one based on chiral crown ether, and another based on polysaccharide derivative, was developed. CROWNPAK® CR-I, the chiral stationary phase bearing (R)- or (S)-(3,30-diphenyl-1,10-binaphtyl)-20-crown-6 (1) moiety is a useful CSP to separate primary amine enantiomers. While perchloric acid had been recommended as the mobile phase additive to attain a better separation, we have reexamined the effect of mobile phase additives and revealed that the retention of an ammonium ion is enhanced by a chaotropic or a hydrophobic anion in a water-based mobile phase like well-known ion pair chromatography in an RPLC. However, the retention was enhanced in reverse by a rather cosmotropic or a hydrophilic anion in an acetonitrile (ACN)-based mobile phase. These results looking contradictory to each other may be rationalized both in the basis of ion pair chromatography. A similar but smaller effect of pairing anion species was also observed on a polysaccharide-based CSP. Based on these findings, some types of mobile phase have been proposed and some of them were demonstrated to be compatible with liquid chromatography-electrospray ionization-mass spectrometry (ESI LC/MS).

Quantification of the aromatase inhibitor letrozole and its carbinol metabolite in mouse plasma by UHPLC-MS/MS

A liquid chromatography - electrospray ionization-mass spectrometry (LC-ESI-MS) method was developed for the quantification of letrozole, a third-generation aromatase inhibitor, and its main carbinol metabolite (CM) in support of murine pharmacokinetic studies. Using polarity switching, simultaneous ESI-MS measurement of letrozole and CM was achieved in positive and negative mode, respectively. The assay procedure involved a one-step protein precipitation and extraction of all analytes from mouse plasma requiring only 5 μL of sample. Separation was optimized on an Accucore aQ column with gradient elution at a flow rate of 0.4 mL/min in 5 min. Two calibration curves per day over four consecutive measurement days showed satisfactory linear responses (r2 > 0.99) over concentration ranges of 5–1000 ng/mL and 20–2000 ng/mL for letrozole and CM, respectively. No matrix effect was found, and the mean extraction recoveries were 103–108 % for letrozole and 99.8–107 % for CM. Precision and accuracy within a single run and over four consecutive measurement days were verified to be within acceptable limits. Application of the developed method to preclinical pharmacokinetic studies in mice receiving oral letrozole at a dose 1 or 10 mg/kg revealed that the systemic exposure to letrozole was dose-, formulation-, and strain-dependent. These findings may inform the future design of preclinical studies aimed at refining the pharmacological profile of this clinically important drug.

Lipidome characterisation and sex-specific differences in type 1 and type 2 diabetes mellitus

BackgroundIn this study, we evaluated the lipidome alterations caused by type 1 diabetes (T1D) and type 2 diabetes (T2D), by determining lipids significantly associated with diabetes overall and in both sexes, and lipids associated with the glycaemic state.MethodsAn untargeted lipidomic analysis was performed to measure the lipid profiles of 360 subjects (91 T1D, 91 T2D, 74 with prediabetes and 104 controls (CT)) without cardiovascular and/or chronic kidney disease. Ultra-high performance liquid chromatography-electrospray ionization mass spectrometry (UHPLC-ESI-MS) was conducted in two ion modes (positive and negative). We used multiple linear regression models to (1) assess the association between each lipid feature and each condition, (2) determine sex-specific differences related to diabetes, and (3) identify lipids associated with the glycaemic state by considering the prediabetes stage. The models were adjusted by sex, age, hypertension, dyslipidaemia, body mass index, glucose, smoking, systolic blood pressure, triglycerides, HDL cholesterol, LDL cholesterol, alternate Mediterranean diet score (aMED) and estimated glomerular filtration rate (eGFR); diabetes duration and glycated haemoglobin (HbA1c) were also included in the comparison between T1D and T2D.ResultsA total of 54 unique lipid subspecies from 15 unique lipid classes were annotated. Lysophosphatidylcholines (LPC) and ceramides (Cer) showed opposite effects in subjects with T1D and subjects with T2D, LPCs being mainly up-regulated in T1D and down-regulated in T2D, and Cer being up-regulated in T2D and down-regulated in T1D. Also, Phosphatidylcholines were clearly down-regulated in subjects with T1D. Regarding sex-specific differences, ceramides and phosphatidylcholines exhibited important diabetes-associated differences due to sex. Concerning the glycaemic state, we found a gradual increase of a panel of 1-deoxyceramides from normoglycemia to prediabetes to T2D.ConclusionsOur findings revealed an extensive disruption of lipid metabolism in both T1D and T2D. Additionally, we found sex-specific lipidome changes associated with diabetes, and lipids associated with the glycaemic state that can be linked to previously described molecular mechanisms in diabetes.

Distribution of Vicine, Convicine and Levodopa in Faba Bean Plant Tissues Determined by UltraHigh Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

Faba bean is an emerging pulse crop for the Canada Prairies and is becoming an increasingly important source of plant sourced protein. It also has a high content of levodopa (up to 0.1 % of the dry seed weight), a nutraceutical compound for treating Parkinson's Disease (PD). The presence of pyrimidine glycosides, vicine and convicine, however, restricts the use of faba due to their potential to cause favism in susceptible individuals. For the rapid separation and quantification of levodopa, vicine and convicine, a 5-min ultrahigh performance liquid chromatography-electrospray ionization mass spectrometry method (UHPLC-ESI MS) was developed. This method provided a wide linear range of quantification (4.8 nM to 60 µM for vicine, and 6.0 nM to 24 µM for convicine and levodopa), and low limit of detection (1.2 to 3.0 nM). The method was applied in the analysis of diverse faba bean samples, from dehulled mature faba bean and seed coat, to fresh plant tissues such as flowers, leaves, stems, roots and pods. The results indicated that fresh faba bean plant tissues, such as leaves and flowers, had the highest concentration of levodopa and low level of VC, which makes them an alternative source of plant-based l-DOPA with potential as a food-based treatment for Parkinson's Disease.

Effectiveness and Biochemical Impact of Flubendiamide and Flonicamid Insecticides against Bemisia tabaci (Hemiptera: Aleyrodidae) and Residue Dissipation in Cherry Tomato Plants and Soil under Greenhouse Conditions

Abstract We investigated the effectiveness and biochemical impact of the insecticides flubendiamide and flonicamid compared with azadirachtin and acetamiprid against the whitefly Bemisia tabaci (Grennadius) (Hemiptera: Aleyrodidae) infesting cherry tomato (Solanum lycopersicum var. cerasiforme L.) grown under greenhouse conditions. The dissipation of both insecticides in the plants and in the soil also was determined using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) and liquid chromatography–electrospray ionization–mass spectrometry methods. Both insecticides were more effective for reducing B. tabaci populations than were either acetamiprid or azadirachtin. Biochemical analysis revealed that esterase may play an important role in whitefly adaptation to flubendiamide and flonicamid. The QuEChERS method was determined suitable for quickly detecting residues of flubendiamide and flonicamid in complex matrices. The recovery rates on tomato fruit samples were 92.8–106.0%, with a relative standard deviation (RSD) range of 0.46–2.65%. For soil samples, the recovery rates were 81.3–95.7% with RSDs of 1.20–3.86%. We further determined that flubendiamide had dissipation half-lives of 3.13, 3.63, and 3.68 d in tomato fruit, tomato leaves, and soil, respectively. Flonicamid had half-lives of 4.25, 3.54, and 2.60 d in fruit, leaves, and soil, respectively. These results suggest that preharvest intervals of 3 and 7 d are appropriate for flubendiamide and flonicamid, respectively, in cherry tomato production. The risk quotient was &amp;gt;1 by the day 5 after application; however, that value declined to &amp;lt;1 on day 7 after application, indicating little long-term risk to human health.

Green synthesis and characterization of silver nanoparticles from Ducrosia flabellifolia Boiss. aqueous extract: Anti-quorum sensing screening and antimicrobial activities against ESKAPE pathogens.

Biosynthesis of silver nanoparticles using natural compounds derived from plant kingdom is currently used as safe and low-cost technique for nanoparticles synthesis with important abilities to inhibit multidrug resistant microorganisms (MDR). ESKAPE pathogens, especially MDR ones, are widely spread in hospital and intensive care units. In the present study, AgNPs using Ducrosia flabellifolia aqueous extract were synthesized using a reduction method. The green synthesized D. flabellifolia-AgNPs were characterized by UV-Vis spectrophotometer, Scanning electron microscopy (SEM), and X-ray diffraction assays. The tested D. flabellifolia aqueous extract was tested for its chemical composition using Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS). Anti-quorum sensing and anti-ESKAPE potential of D. flabellifolia-AgNPs was also performed. Results from LC-ESI-MS technique revealed the identification of chlorogenic acid, protocatechuic acid, ferulic acid, caffeic acid, 2,5-dihydroxybenzoic acid, and gallic acid as main phytoconstituents. Indeed, the characterization of newly synthetized D. flabellifolia-AgNPs revealed spherical shape with mean particle size about 16.961±2.914 nm. Bio-reduction of silver was confirmed by the maximum surface plasmon resonance of D. flabellifolia-AgNPs at 430 nm. Newly synthetized D. flabellifolia-AgNPs were found to possess important anti-ESKAPE activity with low minimal inhibitory concentrations (MICs) ranging from 0.078 to 0.312 mg/mL, and low minimal bactericidal concentrations (MBCs) varying from 0.312 to 0.625 mg/mL. Moreover, D. flabellifolia-AgNPs were active against Candida utilis ATCC 9255, C. tropicalis ATCC 1362, and C. albicans ATCC 20402 with high mean diameter of growth inhibition at 5 mg/mL, low MICs, and minimal fungicidal concentrations values (MFCs). The newly synthetized D. flabellifolia-AgNPs were able to inhibit violacein production in Chromobacterium violaceum, pyocyanin in Pseudomonas aeruginosa starter strains. Hence, the newly synthesized silver nanoparticles using D. flabellifolia aqueous extract can be used as an effective alternative to combat ESKAPE microorganisms. These silver nanoparticles can attenuate virulence of Gram-negative bacteria by interfering with the quorum sensing system and inhibiting cell-to-cell communication.