Ultra-high Performance Liquid Chromatography Research Articles

Characterising and preventing the gut microbiota's inactivation of trifluridine, a colorectal cancer drug

The gut microbiome can metabolise hundreds of drugs, potentially affecting their bioavailability and pharmacological effect. As most gut bacteria reside in the colon, drugs that reach the colon in significant proportions may be most impacted by microbiome metabolism. In this study the anti-colorectal cancer drug trifluridine was used as a model drug for characterising metabolism by the colonic microbiota, identifying correlations between bacterial species and individuals’ rates of microbiome drug inactivation, and developing strategies to prevent drug inactivation following targeted colonic delivery. High performance liquid chromatography and ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometry demonstrated trifluridine's variable and multi-route metabolism by the faecal microbiota sourced from six healthy humans. Here, four drug metabolites were linked to the microbiome for the first time. Metagenomic sequencing of the human microbiota samples revealed their composition, which facilitated prediction of individual donors’ microbial trifluridine inactivation. Notably, the abundance of Clostridium perfringens strongly correlated with the extent of trifluridine inactivation by microbiota samples after 2 hours (R2 = 0.8966). Finally, several strategies were trialled for the prevention of microbial trifluridine metabolism. It was shown that uridine, a safe and well-tolerated molecule, significantly reduced the microbiota's metabolism of trifluridine by acting as a competitive enzyme inhibitor. Further, uridine was found to provide prebiotic effects. The findings in this study greatly expand knowledge on trifluridine's interactions with the gut microbiome and provide valuable insights for investigating the microbiome metabolism of other drugs. The results demonstrate how protection strategies could enhance the colonic stability of microbiome-sensitive drugs.

B-170 Age-Specific reference intervals for ethanolamine plasmalogen species in red blood cells using liquid chromatography tandem mass spectrometry

Abstract Background Plasmalogens are critical membrane structural components that are mainly generated by de novo synthesis starting in peroxisomes. Hence, patients with defects in peroxisome biogenesis (PBD) exhibit markedly reduced plasmalogen levels. Plasmalogen ratios are traditionally measured by gas chromatography-mass spectrometry (GC-MS); however, this method entails a lengthy sample extraction and derivatization and does not report concentrations of individual plasmalogen species. We have developed a robust and easy-to-implement liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify the 18 most abundant ethanolamine plasmalogen (PlsEtn) species in packed red blood cells (RBCs). However, no reference intervals have been published for individual PlsEtn. Here, we describe the establishment of age-specific reference intervals for individual PlsEtn species and their total values (16:0, 18:0, 18:1 species, and total plasmalogens). Methods Plasmalogens were extracted using methanol containing two labeled internal standards, shaking for one hour at room temperature. Chromatographic separation was performed using an Acquity Premier BEH C18 UPLC column with a binary gradient of 5 mM ammonium acetate in water:methanol (15:85) and 5 mM ammonium acetate in methanol. Analysis was performed using a XEVO TQ-XS Mass Spectrometer with Ultra-High Performance Liquid Chromatography (Waters) in multiple reaction monitoring mode. Eighteen PlsEtn species were quantified using four commercially available standards; additionally, totals were calculated for 16:0, 18:0 or 18:1 species, and for total plasmalogens. Reference intervals were established using 376 RBCs from self-reported healthy volunteers and de-identified clinical samples referred for unrelated testing (182 females and 194 males; range 0 to 88 years). Data was analyzed using the R programming language. The study was approved by the Institutional Review Board of the University of Utah. Results Initial age groups were identified using a model-based clustering algorithm followed by iterative Harris-Boyd analysis. Finally, the adjacent groups were merged if their means differed by less than 10%. Once the final age groups were partitioned, data in each individual age group were analyzed using parametric or non-parametric statistics to determine reference intervals (95%, with 90%confidence intervals). PlsEtn species displayed the lowest concentration in the first few months of life, which increased in childhood until adolescence or adulthood (depending on PlsEtn). For most species, the concentrations increased over time reaching a plateau between 18 and 48 years of age, and then starting to decrease. The total values followed the same trend, with neonates showing significantly lower values compared to other age groups. Conclusions We applied a novel statistical approach to identify age groups and determine age-specific reference intervals for 18 individual PlsEtn in RBC and their totals. Lacking previously published data, this study is critical for supporting test implementation in clinical laboratories.

A-066 Does essential fatty acid deficiency alter ethanolamine plasmalogen concentrations in red blood cells? Implications for clinical testing

Abstract Background Plasmalogens are glycerophospholipids characterized by a fatty alcohol at the sn-1 position, a polyunsaturated fatty acid at the sn-2 position, most commonly docosahexaenoic acid (DHA) or arachidonic acid, and a polar head group at the sn-3 position, mainly phosphoethanolamine. Markedly reduced plasmalogens are seen in peroxisome biogenesis defects, including Zellweger spectrum disorders (ZSD), since the first two steps of plasmalogen synthesis occur in peroxisomes. Disruption of the peroxisomal β-oxidation pathway also causes DHA deficiency in ZSD patients. Since plasmalogens are composed of fatty acids, the deficiency of DHA or other essential fatty acids could further decrease the plasmalogen level in ZSD patients and lower the results of plasmalogen testing in patients without ZSD. To test this hypothesis, we evaluated the impact of essential fatty acid (EFA) deficiency on plasmalogens in patients with ZSD and individuals with EFA deficiency due to unrelated causes. Methods Red blood cell (RBC) samples were obtained from individuals without ZSD referred to ARUP laboratories for clinical EFA testing (n = 80; age range: birth - 89 years), and from patients with ZSD (n = 7; age range birth - 9 years). Three ZSD patients were older and with a less severe phenotype. A total of 18 intact ethanolamine plasmalogen species were extracted from packed RBCs and quantified using a XEVO TQ-XS Mass Spectrometer in conjunction with Ultra-High Performance Liquid Chromatography (Waters). Total plasmalogen values were also calculated; plasmalogen deficiency was defined as ≤60% of age-matched control median. Fatty acids (FAs) were quantified by gas chromatography negative chemical ionization-mass spectrometry (GC-NCI-MS). EFA deficiency was diagnosed by increased Triene/Tetraene ratio (Mead acid/Arachidonic acid). Data was analyzed using Prism v.8.3.0 software (La Jolla, CA). The study was approved by the Institutional Review Board of the University of Utah. Results Out of the 80 samples from individuals without ZSD referred for EFA testing, 18% had normal fatty acid profile, 57% were receiving dietary supplements and 25% had elevated Triene/Tetraene ratio suggesting EFA deficiency. EFA deficiency was accompanied by low DHA only in two individuals without ZSD, whereas it was present in most of the samples from ZSD patients evaluated (5/7). None of the individuals without ZSD were deficient in plasmalogens. Moreover, when compared to individuals without ZSD with a normal FA profile, there was no significant difference observed with EFA deficiency or FA supplementation. Although our ZSD cohort is small, no correlation between EFA deficiency and plasmalogen levels was also seen in ZSD: 2 patients with milder phenotype had EFA deficiency but normal plasmalogens, 2 patients had EFA deficiency and low plasmalogens, 2 patients with low plasmalogens had low DHA without EFA deficiency, and 1 patient had low plasmalogens but normal EFA. Conclusions Plasmalogen quantitation in RBCs by LC-MS/MS is not significantly affected by EFA deficiency. Although more data is warranted to elucidate the correlation between plasmalogen levels and ZSD phenotype, plasmalogens can be within normal reference intervals in ZSD regardless of EFA status.

Quantification of Total Ketone Bodies in Biological Matrices Using Stable Isotope-Labeled Internal Standards and RP-UHPLC-MS/MS.

Acetoacetate (AcAc) and D-beta-hydroxybutyrate (D-βOHB), the two major ketone bodies found in circulation, are linked to multiple physiological and pathophysiological states. Therefore, analytical methodologies surrounding the quantification of total ketone body (TKB) concentrations in biological matrices are paramount. Traditional methods to quantify TKBs relied on indirect spectrophotometric assays with narrow dynamic ranges, which have been significantly improved upon by modern mass spectrometry (MS)-based approaches. However, the lack of stable isotope-labeled internal standards (ISs) for AcAc and the need to distinguish D-βOHB from its closely related structural and enantiomeric isomers pose significant obstacles. Here, we provide a protocol to synthesize and quantify a [13C] stable isotope-labeled IS for AcAc, which, in conjunction with a commercially available [2H] stable isotope-labeled IS for βOHB, allows TKBs to be measured across multiple biological matrices. This rapid (7min) analysis employs reverse phase ultra-high performance liquid chromatography (RP-UHPLC) coupled to tandem MS (MS/MS) to distinguish βOHB from three structural isomers using parallel reaction monitoring (PRM), providing excellent specificity and selectivity. Finally, a method is provided that distinguishes D-βOHB from L-βOHB using a simple one-step derivatization to produce the corresponding diastereomers, which can be chromatographically resolved using the same rapid RP-UHPLC separation with new PRM transitions. In summary, this method provides a rigorous analytical pipeline for the analysis of TKBs in biological matrices via leveraging two authentic stable isotope-labeled ISs and RP-UHPLC-MS/MS.

The Pharmacokinetic Interaction of Tirabrutinib with Voriconazole, Itraconazole, and Fluconazole in SD Rats by UPLC-MS/MS.

Tirabrutinib is an orally effective, approved, and highly selective second-generation Bruton's tyrosine kinase (BTK) inhibitor for the treatment of recurrent or refractory primary central nervous system lymphoma (PCNSL). This study aimed to develop an ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) method for the determination of tirabrutinib concentration in rat plasma, where zanubrutinib was used as an internal standard (IS). This method was also applied to study whether tirabrutinib would interact with voriconazole, itraconazole, and fluconazole in rats, providing a reference value for clinical medication guidance. In the current study, the organic solvent protein precipitation method was used to treat plasma samples, which is simple and reproducible. Tirabrutinib (m/z 455.32 → 320.21) and zanubrutinib (m/z 472.13 → 455.04) were separated on a Waters Acquity BEH C18 column (2.1 × 50 mm, 1.7 μm) and detected by multiple reaction monitoring (MRM) in positive ionization mode. The method showed good linearity in the range of 5-3000 ng/mL for tirabrutinib with the lower limit of quantification (LLOQ) of 5 ng/mL. The recovery and matrix effects were 85.7-91.0% and 102.0-113.3%, respectively. The accuracy, precision, stability, and carry-over effect were also acceptable. The method could also be used for determining the pharmacokinetic interaction of tirabrutinib in rats. The results showed AUC0→∞ of tirabrutinib to be increased by 139.3% and 83.9% in the presence of voriconazole and fluconazole, respectively, while itraconazole had little effect. It is necessary to monitor the concentration of tirabrutinib in patients when it is combined with voriconazole and fluconazole to achieve a better therapeutic effect and reduce the risk of adverse reaction. Further research should be conducted in the future.

Isolation and identification of endophytic fungi from Alhagi sparsifolia Shap. and their antibacterial activity

In order to explore the endophytic resources of Alhagi sparsifolia Shap. and identified novel antibacterial substances. Thirty endophytic fungal strains were isolated from the stems and roots of A. sparsifolia Shap. Morphological and molecular biology methods were used to identify ten strains of fungi, including four strains of Aspergillus niger, three strains of Alternaria alternata, two strains of Aspergillus flavus, and one strain of Fusarium incarnatum. All these strains were isolated from A. sparsifolia Shap. for the first time, and of these Aspergillus was the dominant genus. Antibacterial activity of the ten strains against Escherichia coli, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa were evaluated using the disc diffusion method. The results demonstrated that the metabolites from all the strains had inhibitory effects on at least one indicator bacterium. Notably, the endophytic fungi AFJ3 and AFG6 demonstrated strong broad-spectrum antibacterial activity, particularly against E. coli, with inhibition zones measuring 32.0 ± 0.3 and 31.3 ± 0.3 mm, respectively. The three endophytic fungi (AFG1, AFG2, and AFG3) isolated from the roots demonstrated significant antibacterial activity against P. aeruginosa forming an inhibition zone of diameter 31.3 ± 0.1, 25.6 ± 0.2, and 25.6 ± 0.2 mm, respectively. However, the strains of endophytic fungi demonstrated no significant inhibitory effects on C. albicans. Ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry/mass spectrometry (UPLC-QTOF-MS/MS) analysis depicted that the ethyl acetate phase of AFJ3 and AFG6 fermentation broth predominantly contained organic acids, phenolic acids, flavonoids, and fatty acids. These secondary metabolites often exhibited good antibacterial activity. This study broadens our understanding of endophytic fungi in A. sparsifolia Shap. The antibacterial activity of some strains of endophytic fungi was significant, making it worthy of further research on their active material.

Phytochemical screening, characterization, and in vitro anti-metastatic effects of the methanolic leaf extract of Momordica cardiospermoides in MDA-MB 321 cells

Introduction: Momordica cardiospermoides represents an inexhaustible source of natural products. We examined the acetone and methanolic extracts of M. cardiospermoides leaves’ phytochemical composition, antioxidant activities, and anti-metastatic properties in MDA-MB-231 cells. Methods: The aluminium chloride and Folin-Ciocalteu methods were employed to determine the extracts’ phytochemical contents. Assessment of antioxidant activities employed the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The extracts were further characterized with ultra-high-performance liquid chromatography (UHPLC). The cell count and viability kit were utilized to assess viability in HEK-293 and MDA-MB-231 cells. The occurrence of cell death was determined by the annexin V and dead cell assay. The methanolic extract was assessed against cell adhesion and migration using the cell-extracellular matrix and wound healing assays. The effects of the methanolic extract on tissue inhibitors, including metalloproteinase-1 (TIMP-1), matrix metalloproteinases-2 (MMP-2), and -9 (MMP-9) were determined by the human angiogenesis antibody array kit and Western blot analysis. Results: The acetone extract had higher antioxidant activity and total contents than the methanolic extract. UHPLC revealed abundant luteolin, luteoloside, quercetin, stearidonic acid, and salicylamide in the acetone extract, and luteolin, astragalin, and trigonelline in the methanolic extract. The methanolic extract was selectively cytotoxic towards MDA-MB-231 cells while the acetone extract was significantly cytotoxic in both cell lines. Apoptosis was induced by the methanolic extract and the acetone extract induced significant necrosis. The methanolic extract suppressed migration by significantly inhibiting wound closure and inhibited cell adhesion. MMP-2 and MMP-9 were significantly downregulated and TIMP-1 was upregulated. Conclusion: The methanolic extract M. cardiospermoides possesses anti-metastatic activity.

Isolation of a novel Bacillus subtilis HF1 strain that is rich in lipopeptide homologs and has strong effects on the resistance of plant fungi and growth improvement of broilers.

Bacillus subtilis is an important probiotic microorganism that secretes a variety of antimicrobial compounds, including lipopeptides, which are a class of small molecule peptides with important application value in the fields of feed additives, food, biopesticides, biofertilizers, medicine and the biological control of plant diseases. In this study, we isolated a novel B. subtilis HF1 strain that is rich in lipopeptide components and homologs, has a strong antagonistic effect on a variety of plant fungi, and is highly efficient in promoting the growth of broilers. The live B. subtilis HF1 and its fermentation broth without cells showed significant inhibitory effects on 20 species of plant fungi. The crude extracts of lipopeptides in the fermentation supernatant of B. subtilis HF1 were obtained by combining acid precipitation and methanol extraction, and the lipopeptide compositions were analyzed by ultrahigh-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The results showed that HF1 could produce 11 homologs of surfactin and 13 homologs of fengycin. Among the fengycin homologs, C13-C19 fengycin A and C15-C17 fengycin B were identified; among the surfactin homologs, C11-C17 surfactin A and C13-C16 surfactin B were characterized. C13 fengycin A, C11 surfactin A and C17 surfactin A were reported for the first time, and their functions are worthy of further study. In addition, we found that HF1 fermentation broth with and without live cells could be used as a feed additive to promote the growth of broilers by significantly increasing body weight up to 15.84%. HF1 could be a prospective strain for developing a biocontrol agent for plant fungal diseases and an efficient feed additive for green agriculture.

Metabolomics of basal tears in amyotrophic lateral sclerosis: a cross-sectional study

PurposeAmyotrophic lateral sclerosis (ALS) clinical variability, along with the lack of conclusive diagnostic instruments, result in average diagnosis delays of 9 months. This study aimed to assess whether metabolomic profiling of basal tears in ALS patients could act as a biological marker for diagnosing ALS, predicting prognosis, and discriminating between endophenotypes. MethodsA single-center prospective case-control study was conducted in France from September 2021 to March 2023 including patients with ALS according to the revised EI Escorial criteria. Two microliters of basal tears were collected using microcapillary glass tubes and analyzed with ultra-high performance liquid chromatography coupled with mass spectrometry. Both univariate and multivariate analyses were performed. ResultsTwenty-five patients with ALS and 30 controls were included. No significant differences in metabolite levels were found between ALS and control groups (p>0.05). The basal tear metabolome significantly discriminated bulbar and spinal forms of ALS based on 6 metabolites, among which 5 were decreased (aniline, trigonelline, caffeine, theophylline and methyl beta-D-galactoside) in the bulbar form and 1 was decreased in the spinal form (dodecanedioic acid). ConclusionThis study represents the first prospective analysis of basal tear metabolomics in individuals with ALS. Despite the inability to distinguish between ALS patients and controls based on metabolic signatures, these findings could contribute to understanding the phenotypic diversity of ALS. Notably, distinct metabolic profiles were identified that differentiate between the bulbar and spinal forms of the disease.

Simultaneous detection of multiple mycotoxins in Radix Dipsaci and estimation of exposure risk for consumers

Like many traditional Chinese herbal medicines, preparations from Radix Dipsaci are at risk of contamination by harmful mycotoxins; however, there have been no reports of actual contamination. In this study, we developed an analytical method to simultaneously detect eight mycotoxins in Radix Dipsaci and estimate the exposure risk for consumers. We have developed an analytical method utilizing ultra-high performance liquid chromatography and tandem mass spectrometry to accurately determine the levels of AFB1, AFB2, AFG1, AFG2, OTA, ZEN, T-2 and ST mycotoxins in 45 batches of Radix Dipsaci sourced from major medicinal herb markets across five regions in China. We also analyzed migration of mycotoxins from the raw herbs into water decoction. Based on these results and data on human consumption of the herbal medicine, we estimated risk of exposure and acceptable exposure limits to mycotoxins in the Radix Dipsaci using the “margin of exposure (MOE)” method. Of the 45 batches of Radix Dipsaci, 48.89% contained at least one of the eight mycotoxins, 24.44% contained one, 17.78% contained two and 6.67% contained three. The most frequent mycotoxins were aflatoxin B1, present in 35.56% of batches (at 0.25–34.84 μg/kg); aflatoxin G1, 15.56% (1.99–44.05 μg/kg); and ochratoxin A, 22.22% (16.11–143.38 μg/kg). These three mycotoxins transferred from the raw herb into water decoction at respective rates of 20.20%, 29.14%, and 24.80%. The 95th percentile values of the MOE risk factors for health effects of AFB1 were below 10,000 at high doses but above 10,000 at low doses of Radix Dipsaci long-term treatment. With the reduction in duration of exposure years, the MOE values of AFB1 and AFG1 gradually reverted to within the acceptable range. The mean, 50th, and 95th percentile values of the MOE risk factors for health effects of OTA exceeded 10,000 regardless of whether consumers received a low or high dose of Radix Dipsaci treatment for durations ranging from 1 to lifetime. Based on this exposure and a typical human diet, we have estimated the respective 20-year exposure limits for Radix Dipsaci to be 5.821 μg/kg, 4.035 μg/kg, and 56.073 μg/kg for the three mycotoxins under consideration. Contamination with multiple mycotoxins is frequently observed in Radix Dipsaci, and the three most prevalent contaminants have been found to leach into water decoctions, thereby posing a potential health hazard for individuals consuming this herbal preparation. This work highlights the need to monitor herbal medicines for mycotoxin contamination in order to protect consumers.

Structural characterization and bioactivity profiling of the fungal peptaibiotic tolypin reveal protective effects against influenza viruses.

In a bioprospection for new antivirals, we tested nonribosomally biosynthesized polypeptide antibiotics in MDCK II cells for their actions on influenza A and B viruses (IAV/IBV). Only tolypin, a mixture of closely related 16-residue peptaibiotics from the fungus Tolypocladium inflatum IE 1897, showed promising activity. It was selected for further investigation and structural characterization byultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HR-MS/MS) and ultrahigh performance liquid chromatography coupled to in-source collision-induced dissociation tandem mass spectrometry (UHPLC-isCID-HR-MS/MS), revealing 12 partially co-eluting individual peptides that were fully sequenced. Since tolypin-related efrapeptins are potent inhibitors of F1/Fo-ATPase, we screened tolypin for its toxicity against MDCK II cells and larvae of the greater wax moth Galleria mellonella. We found that a nontoxic concentration of tolypin (1 µg/mL) reduced the titer of two IBV strains by 4-5 log values, and that of an H3N2 strain by 1-2 log values, but the H1N1pdm strain was not affected. The higher concentrations of tolypin were cytostatic to MDCK II cells, shifted their metabolism from oxidative phosphorylation to glycolysis, and induced paralysis in G. mellonella, supporting the inhibition of F1/Fo-ATPase as the mode of action. Our results lay the foundations for future work to investigate the interplay between viral replication and cellular energy metabolism, as well as the development of drugs that target host factors.

Quantification of tricyclic glycopeptide in human plasma by UHPLC-MS3 coupled with counter-extraction follow by protein precipitation to enhance sensitivity

An ultra-high performance liquid chromatography tandem mass spectrometry cubed (UHPLC/MS3) assay coupled with protein precipitation and counter-extraction for detection of tricyclic glycopeptide vancomycin in human plasma was established and validated in this study. After protein precipitation and counter-extraction with dichloromethane, chromatographic separation of vancomycin and norvancomycin were performed on a reversed phase column (XBridge Peptide BEH C18 column, 2.1 × 100 mm I.D, 3.5 μm). The transition (parent ions → fragment ions → further fragment ions) at m/z 725.3 → 144.1 → 100.1 was used for quantification of vancomycin. The transition (parent ions → fragment ions) at m/z 718.3 → 144.2 was used for detection of norvancomycin. The linear range of the developed analytical method for quantification of vancomycin was 0.5–100 µg/mL (r = 0.9989). The range of intra- and inter-day precisions of the assay among low, medium and high concentrations is between 1.88 % and 6.33 %. The sensitivity of the analytical method was significantly improved by using MS3 technique as monitoring mode and counter-extraction with dichloromethane followed by protein precipitation as sample processing assay. The developed UHPLC/MS3 assay was successfully applied for clinical therapeutic drug monitoring (TDM) of vancomycin in 45 human plasma samples.

Regulatory network analysis reveals gene-metabolite relationships in pear fruit treated with methyl jasmonate

The economic value of pear is determined by its intrinsic qualities, which are influenced by metabolites produced during the ripening process. Methyl jasmonate (MeJA), a hormone, plays an important role in plant metabolism. To date, few studies have investigated the molecular mechanism underlying the changes in metabolic pathways related to the internal quality of pear fruit after MeJA treatment. In this study, ultrahigh-performance liquid chromatography‒Q Exactive Orbitrap mass spectrometry (UHPLC‒QE‒MS) was used to determine the changes in metabolite contents in pear after MeJA treatment. MeJA treatment primarily activated carbohydrate metabolism and amino acid metabolism pathways. Through combined analysis of UHPLC‒QE‒MS data and whole-transcriptome data, the abovementioned pathways and each metabolite were analysed separately, and competitive endogenous RNA (ceRNA) and microRNA–transcription factor–target (miRNA–TF–target) regulatory networks were constructed. The core nodes of three genes (PEA, Pbr022732.1; GAA, Pbr035655.1; and miR8033-x) and two genes (SDS, Pbr031708.1; and novel-m6796-3p) were associated with the carbohydrate metabolism and amino acid metabolism pathways, respectively. The core mRNA nodes TCONS_00048038 and Pbr019584.1, the core miRNA node miR4993-x, the core lncRNA node TCONS_0004356, the core circRNA node novel_circ_001967 and the core transcription factor node TSO1 (Pbr025407.1) were identified via separate metabolite analyses. These findings elucidate the changes in metabolites related to fruit quality in ‘Nanguo’ pear and the relationships between the metabolites and genes, reveal the molecular mechanism underlying the response of MeJA treatment in pear fruit, and provide a theoretical basis for improving the internal quality of ‘Nanguo’ pear.

Rapid screening of xanthine oxidase inhibitors from Ligusticum wallichii by using xanthine oxidase functionalized magnetic metal-organic framework.

In this study, xanthine oxidase was immobilized for the first time using a novel magnetic metal-organic framework material (Fe3O4-SiO2-NH2@MnO2@ZIF-8-NH2). A ligand fishing method was established to rapidly screen XOD inhibitors from Ligusticum wallichii based on the immobilized XOD. Characterization and properties of the immobilized enzyme revealed its excellent stability and reusability. A ligand was screened from Ligusticum wallichii and identified as ligustilide by ultra-high performance liquid chromatography tandem mass spectrometry. The IC50 value of ligustilide was determined to be 27.70 ± 0.13μM through in vitro inhibition testing. Furthermore, molecular docking verified that ligustilide could bind to amino acid residues at the active site of XOD. This study provides a rapid and effective method for thepreliminary screening of XOD inhibitors from complex natural products and has great potential for further discovery of anti-hyperuricemic compounds.

Ultra high-performance liquid chromatography tandem mass spectrometry: Development and validation of an analytical method for N2-Ethyl-2’-deoxyguanosine in dried blood spot

In the body, ethanol is metabolized to acetaldehyde by alcohol dehydrogenase and CYP2E1. Acetaldehyde is the main carcinogen that forms DNA adducts, N2-Ethylidene-2'-deoxyguanosine (N2-Ethylidene-dG), which can cause DNA damage and lead to cancer. However, N2-Ethylidene-dG is an unstable form at the nucleoside level and is difficult to measure. So it needs to be reduced using NaBH4 to become N2-Ethyl-2'-deoxyguanosine (N2-Et-dG). This study aims to obtain a selective, sensitive, and validated analytical method to determine N2-Et-dG using ultra-high-performance liquid chromatography-tandem mass spectrometry with allopurinol as the internal standard. The N2-Et-dG analysis was performed using a C18 Acquity® Bridged Ethylene Hybrid column of (1.7 μm, 100 mm × 2.1 mm). The sample matrix used was dried blood spots, and then the DNA sample was extracted using the QIAamp DNA Mini Kit. The optimum analysis conditions were obtained in a combination eluent of 0.1 % acetic acid and methanol (60:40 v/v) with a flow rate of 0.1 mL/min and eluted isocratically for 5 min. Quantification analysis was performed using triple quadrupole mass spectrometry with electrospray ionization in positive mode, with detection at m/z 296.16 > 180.16 for N2-Et-dG and 137.03 > 110.05 for allopurinol, respectively. The validated analytical method follows the 2018 USA Food and Drug Administration guidelines with a linear concentration range of 5–200 ng/mL.

UPLC Estimation of an Antidiabetic Drug by Method Development and Validation Followed by Stability Indicating Studies.

The analytical method development and validation of a common antidiabetic drug, Canaglifozin, by taking the aid of ‘Ultra High-Performance Liquid Chromatography’, along with stability indicating method. The canaglifozin drug was eluted from the optimized mobile phase in 70:30 ratio of water and methanol, at 1 ml/ min flow rate, under separation with C18 column of 100 x 2mm size with 1.8 diameters at isocratic mode. The detection was carried at 286 nm wavelength, resulting in 3.80 retention time, as run time being 10 min. The detection limit and quantification limit, was noticed at ‘0.0039 and 0.0119 µg/ ml’ correspondingly. The percentage RSD and recovery percentage was under ICH guidelines only. The stress degradation studies under acid, basic, neutral, and thermal conditions were carried on.

Integrating network pharmacology, molecular docking and non-targeted serum metabolomics to illustrate pharmacodynamic ingredients and pharmacologic mechanism of Haizao Yuhu Decoction in treating hyperthyroidism.

To explore the pharmacodynamic ingredients and pharmacologic mechanism of Haizao Yuhu Decoction (HYD) in treating hyperthyroidism via an analysis integrating network pharmacology, molecular docking, and non-targeted serum metabolomics. Therapeutic targets of hyperthyroidism were searched through multi-array analyses in the Gene Expression Omnibus (GEO) database. Hub genes were subjected to the construction of a protein-protein interaction (PPI) network, and GO and KEGG enrichment analyses. Targets of active pharmaceutical ingredients (APIs) in HYD and those of hyperthyroidism were intersected to yield hub genes, followed by validations via molecular docking and non-targeted serum metabolomics. 112 hub genes were identified by intersecting APIs of HYD and therapeutic targets of hyperthyroidism. Using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) in both negative and positive ion polarity modes, 279 compounds of HYD absorbed in the plasma were fingerprinted. Through summarizing data yielded from network pharmacology and non-targeted serum metabolomics, 214 common targets were identified from compounds of HYD absorbed in the plasma and therapeutic targets of hyperthyroidism, including PTPN11, PIK3CD, EGFR, HRAS, PIK3CA, AKT1, SRC, PIK3CB, and PIK3R1. They were mainly enriched in the biological processes of positive regulation of gene expression, positive regulation of MAPK cascade, signal transduction, protein phosphorylation, negative regulation of apoptotic process, positive regulation of protein kinase B signaling and positive regulation of MAP kinase activity; and molecular functions of identical protein binding, protein serine/threonine/tyrosine kinase activity, protein kinase activity, RNA polymerase II transcription factor activity, ligand-activated sequence-specific DNA binding and protein binding. A total of 185 signaling pathways enriched in the 214 common targets were associated with cell proliferation and angiogenesis. HYD exerts a pharmacological effect on hyperthyroidism via inhibiting pathological angiogenesis in the thyroid and rebalancing immunity.

Citrus flavonoid-pectin conjugates with enhanced emulsifying properties

Pectin and flavonoids are important components of citrus fruits, but the effects of flavonoid grafting on the emulsifying properties of citrus pectin remain unclear. In this study, a novel natural citrus flavonoid-pectin conjugate in citrus peel was identified through alkaline hydrolysis combined with ultra-high performance liquid chromatography. Subsequently, two major citrus flavonoids were enzymatically conjugated to citrus pectin at high grafting rates (hesperidin: 20.21%; naringin dihydrochalcone: 16.11%). The flavonoids increased pectin amphipathy while ensuring a tighter conformation and denser network structure. These structural changes reduced the interfacial tension (from 20.6 to 18.4 mN/m) and increased the adsorbed layer thickness (from 11.8 to 37.8 nm), facilitating rapid pectin anchoring at the oil-water interface. These led to smaller droplet size and better emulsion stability. Prepared flavonoid-pectin conjugates with high grafting rates exhibited better emulsifying properties than those with medium grafting rates; hesperidin-pectin conjugates were more effective than naringin dihydrochalcone-pectin conjugates. The prepared flavonoid-pectin conjugates aid in the structural identification of natural flavonoid-pectin conjugates; they also facilitate analyses of the properties of these conjugates and offer new insights into improving the functional properties of pectins used in the food industry.

Multi-residue analysis method based on QuEChERS followed by ultra-high performance liquid chromatography coupled with diode-array detector for pesticides in human serum and breast milk.

Background: Maternal fluids play a key role in the risk assessment regarding early life pesticide exposure as the chemicals can transfer to neonate through prenatal exposure and lactation.Aim: A developed UHPLC-DAD and modified QuChERS methods were validated for human serum and breast milk. Matrix effect of the biological samples were evaluated.Methods & results: Serum was extracted by unbuffered QuChERS method while breast milk was extracted by citrate buffered method with addition of hexane. Remaining lipid in breast milk extract was later removed using lipid-removal sorbent. Sample matrices caused huge impacted on low-sensitivity pesticides.Conclusion: The modified QuEChERS methods coupled with UHPLC-DAD were fully validated. Application in paired-serum and breast milk samples revealed 6 detected pesticides.

Maidong Dishao Decoction mitigates submandibular gland injury in NOD mice through modulation of gut microbiota and restoration of Th17/Treg immune balance

BackgroundPrimary Sjogren's syndrome (pSS) is a common chronic autoimmune disease that presents limited treatment options and poses significant challenges for patients. Maidong Dishao Decoction (MDDST), a traditional Chinese medicine compound, has demonstrated potential in alleviating dryness symptoms associated with pSS. Therefore, it is important to study the specific mechanism of its therapeutic effect. ObjectiveThis study aims to investigate the effects of MDDST on gut microbiota, short-chain fatty acids (SCFAs), and the Th17/Treg immune balance in non-obese diabetes (NOD) mice. MethodsThe study employed ultrahigh-performance liquid chromatography coupled with quadrupole-exactive mass spectrometry (UHPLC-QE-MS) to identify the primary components of MDDST. Subsequently, hematoxylin and eosin (HE) staining, enzyme-linked immunosorbent assays (ELISA), and flow cytometry analyses were conducted to evaluate the therapeutic effects of MDDST in NOD mice. Additionally, 16S rDNA sequencing and gas chromatography-mass spectrometry (GC-MS) were utilized to assess the influence of MDDST on gut microbiota and SCFAs. Finally, fecal microbiota transplantation (FMT) and SCFA-based interventions were performed to elucidate the mechanisms through which MDDST exerts its effects. ResultsThe research findings demonstrate that MDDST exerts therapeutic effects on NOD mice, primarily manifested as reduced inflammation, decreased water intake, ameliorated pathological changes and lowered levels of Sjogren's syndrome antigen A (SSA) and immunoglobulin G (IgG). Additionally, MDDST significantly decreased serum levels of interleukin-6 (IL-6) and interleukin-17 (IL-17), while enhancing levels of interleukin-10 (IL-10) and transforming growth factor beta (TGF-β), thereby regulating the Th17/Treg immune balance. Further investigations revealed that MDDST treatment induces alterations in gut microbiota composition and elevates SCFA levels in the gut. Subsequent FMT and SCFA intervention experiments demonstrated a downregulation of pSS-related phenotypes. ConclusionIn summary, MDDST demonstrates protective effects against pSS by restoring the balance between Th17 and Treg cells. The therapeutic effects can be partially attributed to its regulation of gut microbiota and SCFAs. Our finding provides a new option for treating pSS.