Ultra-high Performance Liquid Chromatography Research Articles

Effects of relative humidity on atmospheric organosulfur species derived from photooxidation and nocturnal chemistry in a forest environment

The molecular composition of organic aerosols in ambient PM2.5 was investigated at the northern foothills of Qinling Mountain region in central China during the summer of 2022. The molecular characteristics of organic matter were analyzed using ultrahigh performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry. The number of molecular formula assignments was dominated by organosulfur species (OrgS, on average 28–47% in total). Both the number and peak area of OrgS increased significantly with higher relative humidity (RH), while those of CHO and CHON species decreased, indicating the different impacts of RH on individual organic groups. The entire study period was divided into two distinct stages, including a low RH and a high RH period (LRH and HRH). The enhanced formation of CHOS with O>7 in HRH was primarily attributed to photochemical oxidation, whereas the increase in CHONS with O>7 was driven by enhanced NO3 radical-initiated oxidation under elevated RH conditions. Nearly 50% of OrgS presented only in HRH had aliphatic structures with C≥9. Although isoprene-derived organosulfates dominated the peak area across the entire period, the monoterpenes and long-chain alkanes-derived organosulfates largely increased in HRH. The strong correlations between aerosol liquid water content and OrgS containing high oxygen content (O>7) indicate that aqueous-phase reactions played a crucial role in multigenerational oxidation of OrgS. This study highlights the important effects of RH on the formation of OrgS, particularly for organosulfates derived from monoterpenes and long-chain alkanes.

The Ontogeny and Dietary Differences in Queen and Worker Castes of Honey Bee (Apis cerana cerana)

The honey bee Apis cerana cerana (A. c. cerana), a subspecies of Apis cerana, is endemic in China and possesses a valuable ecological niche. Understanding the ways to protect this honey bee’s populations is crucial, but this topic has been understudied. For the efficient utilization of beekeeping and pollination, there is a need to explore its biology and management practices. In light of this, the current study was carried out to investigate the ontogeny and dietary differences in the queen and worker castes of the A. c. cerana honey bee. This article presents, supplemented by reference images, a detailed description of the life history of A. c. cerana queens and workers. Additionally, this study investigated the nutritional differences between royal jelly (RJ) and worker jelly (WJ) at various larval ages. The contents of the moisture, crude protein, and amino acids in RJ and WJ were determined via freeze drying, Kjeldahl nitrogen determination, and ultra-high performance liquid chromatography. The results highlight significant variations in the moisture content, crude protein concentration, and amino acid concentration between RJ and WJ. The results offer theoretical support for ex situ artificial rearing practices of A. c. cerana.

Differentiation of Ayahuasca Samples According to Preparation Mode and Botanical Varieties Using Metabolomics

ABSTRACT Ayahuasca is a brew traditionally prepared with a mixture of Psychotria viridis leaves and Banisteriopsis caapi vine and has demonstrated therapeutic properties for depression. Knowledge of the brew composition is important to improve the therapeutic potential and decrease side effects if ayahuasca becomes an option for refractory depression treatment. Ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) was applied to analyze 126 ayahuasca samples collected from different ayahuasqueiro groups and geographic origins. We were able to observe a differentiation in the metabolite composition of ayahuasca samples prepared by diverse ayahuasqueiro groups. These samples presented different antioxidant effects based on FRAP and ORAC assays. Exploratory statistical analysis demonstrated a trend of separating the samples according to the religious group. The most important identified compounds for differentiation of the brew prepared by distinct religious groups are glycosylated and/or phenolic compounds. The comparison based on the mode of ayahuasca preparation presented more variability than the comparison based on the botanical variety of B. caapi used. We conclude that ayahuasca samples prepared with “caupuri” or “tucunacá” separately exhibited differences in the analysis of L-glutamate and the metabolism of arginine and proline. This suggests that a possible variation in this pathway could explain the occurrence of swollen stem nodes in “caupuri,” one of the B. caapi varieties.

Identification of active ingredients in Naomaitai capsules using high-resolution mass spectrometry unite molecular network analysis and prediction of their action mechanisms.

Although Naomaitai capsule (NMC) is widely used in clinical practice and has a good curative effect for cerebral infarction, its material basis and mechanism of action remain unclear. In this study, ultra-high-performance liquid chromatography (UHPLC) coupled with quadrupole Orbitrap MS technology was used to analyse the in vivo and in vitro components of NMC, and the Global Natural Products Social Molecular Networking website was used to further analyse the components of NMC. Next, systems biology approaches were employed to investigate the mechanism of action of NMC. Finally, molecular docking technology was used to verify the network pharmacological results. In total, 177 compounds were identified in vitro, including 65 terpenoids, 62 flavonoids, 25 organic acids and 11 quinones. 64 compounds were identified in the blood of mice, and the main active components included ginkgolide C, ginkgolide A, ligustilide, tanshinone IIB, olmelin, emodin and puerarin. The main targets in vivo included TP53, SRC, STAT3, PIK3CA and PIK3R1. In conclusion, this study has revealed that NMC acts on multiple targets in the body through various active components, exerting synergistic effects in the treatment of CI. Its mechanism of action may involve inhibiting neuronal apoptosis, oxidative stress and inflammatory responses as well as reducing cerebral vascular permeability and promoting cerebral vascular regeneration.

Simultaneous Quantification of Carboxylate Enantiomers in Multiple Human Matrices with the Hydrazide-Assisted Ultrahigh-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry.

Many chiral carboxylic acids with α-amino, α-hydroxyl, and α-methyl groups are concurrently present in mammals establishing unique molecular phenotypes and multiple biological functions, especially host-microbiota symbiotic interactions. Their chirality-resolved simultaneous quantification is essential to reveal the biochemical details of physiology and pathophysiology, though challenging with their low abundances in some biological matrices and difficulty in enantiomer resolution. Here, we developed a method of the chirality-resolved metabolomics with sensitivity-enhanced quantitation via probe-promotion (Met-SeqPro) for analyzing these chiral carboxylic acids. We designed and synthesized a hydrazide-based novel chiral probe, (S)-benzoyl-proline-hydrazide (SBPH), to convert carboxylic acids into amide diastereomers to enhance their retention and chiral resolution on common C18 columns. Using the d5-SBPH-labeled enantiomers as internal standards, we then developed an optimized ultrahigh-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous quantification of 60 enantiomers of 30 chiral carboxylic acids in one run. This enantiomer-resolved method showed excellent sensitivity (LOD < 4 fmol-on-column), linearity (R2 > 0.992), precision (CV < 15%), accuracy (|RE| < 20%), and recovery (80-120%) in multiple biological matrices. With the method, we then quantified 60 chiral carboxylic acids in human urine, plasma, feces, and A549 cells to define their metabolomic phenotypes. This provides basic data for human phenomics and a promising tool for investigating the mammal-microbiome symbiotic interactions.

UHPLC-QQQ-MS/MS method for the simultaneous quantification of 18 amino acids in various meats.

Amino acids are an essential source of human protein, and their content and composition are the main factors determining food protein utilization rate. Determining amino acids is essential in the component analysis of food. Therefore, a groundbreaking technique was developed utilizing ultra-high performance liquid chromatography interfaced with a triple quadrupole mass spectrometer (UHPLC-QQQ-MS/MS) for concurrently quantifying 18 amino acids across various types of meat. According to the test results, it can be known that the average content of glutamate (2.03 × 104 ± 3.94 × 103 μg/g in pig feet) was the highest in all meat samples, and the content of aspartate (0.0945 ± 0.0950 μg/g in pork) was the lowest, which was not detected in some samples such as beef and lean meat. Orthogonal partial least-squares discrimination analysis (OPLS-DA) showed: (1) 13 amino acids (arginine, valine, serine, alanine, lysine, glycine, asparagine, methionine, proline, threonine, glutamate, phenylalanine, and leucine, VIP > 1) were used as characteristic amino acids between pork and pig feet; (2) serine, threonine, alanine, histidine, asparagine, and arginine (VIP > 1) were used as signature amino acids in different components of pork (lean meat, fat, and pigskin); (3) asparagine, glutamate, histidine, tyrosine, and valine (VIP > 1) were considered as signature amino acids in different types of meats (pork, mutton, beef, and chicken). This study provides a new UHPLC-QQQ-MS/MS method for the determination of amino acid content in meat and also provides data support for the comprehensive evaluation of the nutritional value of foods containing amino acids.

High-Resolution Tandem Mass Spectrometry for Metabolic Profiling of Ocotea diospyrifolia (Meisn.) Mez Leaves.

Ocotea is an important genusof Lauraceae plant familythat comprises over 400 species, many of which pose challenges in taxonomicdifferentiation due to their complex botanical characteristics. Chemosystematics, and more recently, chemophenetics, have emerged as valuable tools to address these challenges based on their natural products (NPs) composition. O. diospyrifolia (Meisn.) Mez is a poorly studied species with known pharmacological potential. Here, we applied ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS) allied to a curated in-house database with all previous isolated NPs from the Ocotea genus (OcoteaDB), gas phase fragmentations reactions, and biosynthesis. The strategy resulted in compounds annotated in confidence levels 2 (n=27), 3 (n=231), and 4 (n=21) according to the Metabolomics Standards Initiative (MSI). Additional annotations based on fragmentation proposals (n=16) were also included. The study revealed that O. diospyrifolia is a great alkaloid producer, even though different lignoids, which also comes from the shikimate pathway, were annotated. Additionally, the flavonoid profile predominantly consists of flavonol glycosides, complementing prior reports. This study provides the first comprehensive chemical profile of O. diospyrifolia leaves, which corroborates the chemotaxonomy of the species, and also contributes to further characterization studies, as the UHPLC-HRMS data is publicly available.

IMPACT OF CYP2D6 POLYMORPHISMS IN PREDUCTING OCCURRENCE OF ADVERSE EFFECT TO TAMOXIFEN AND DEVELOPING RECCURENCE IN ER+ BREAST CANCER PATIENETS:

Objectives: Breast cancer is a major public health in Algeria. Tamoxifen has been approved in the treatment of ER+ breast cancer. Some of negative side effects of tamoxifen are frequently a reason for discontinuation of therapy during treatment, which would otherwise be potentially lifesaving. In the current study, we assessed the association between CYP2D6 polymorphisms and tamoxifen efficacy in Algerian population receiving tamoxifen as adjuvant therapy in ER+ breast cancer. Methods: A total of 76 Algerian hormone receptor-positive premenopausal breast cancer patients with adjuvant tamoxifen treatment were investigated (45.36±6.13). DNA genotyping was performed by TaqMan Open Array technology. Tamoxifen and its metabolites levels were measured by ultra-high-performance liquid chromatography (UHPLC) followed by electro spray tandem mass spectrometry (LC-MS/MS). Results: A significant association between the presence of deficit copy of enzyme activity and development of adverse effect after the commencement of tamoxifen therapy. Low plasma endoxifen were observed in patients categorized as (NM/PM), (IM/ IM), (IM/PM) and (PM/PM). Patients with increased plasma endoxifen concentrations were significantly more likely than patients with reduced or null activity to not report recurrences (P&lt;0.05). We realized that the combination genotypes NM/PM, IM/IM, IM/PM, with PM/PM were more strongly associated with disease recurrence and adverse effects than NM carries of CYP2D6*1 allele (P&lt;0.05). Conclusion: Our results affirm that CYP2D6 polymorphism should be considered in predicting the occurrence of adverse effect fatty liver in women treated with tamoxifen. Thus, alternative treatment can be intended and lifestyle modifications can be implemented

AF4-UHPLC: Two-dimensional separation of macromolecules in four white wines from South-Western France

Proteins in wines contribute to “protein haze,” which, while not affecting health or taste, can detract from the visual appeal of wines to consumers. To mitigate this issue, winemakers commonly use fining agents such as bentonite, despite the high costs involved. To overcome these challenges, numerous studies employ various analytical methods to better understand the behaviour of proteins. A novel technique which separates compounds by size, Asymmetrical Flow-Field Flow Fractionation (AF4), allows for studying proteins without denaturing them. Given that most proteins share similar sizes, identification remains challenging. The aim of this work was initially to develop a new system enabling simultaneous analysis of the macromolecular profile of wines (proteins, mannoproteins) using AF4 and real-time protein nature analysis (hydrophobicity properties) using Ultra-High Performance Liquid Chromatography (UHPLC). By injecting two standards of different sizes and chemical nature, thaumatin protein and mannoproteins, the system was validated. The subsequent application of this system to Southwestern wines revealed distinct profiles across monovarietal white wines from four grape varieties. While the Colombard (COL) and Gros manseng (GM) varieties showed similar protein compositions with varying concentrations, the Len de l'el (LL) variety had only two types of protein and no protein was detected in the Mauzac (MZ) variety. Despite these variations, all varieties contained mannoproteins. This system shows promise for studying wine protein composition and could potentially find applications in other matrices.

Processing-induced reduction in dianthrones content and toxicity of Polygonum multiflorum: Insights from ultra-high performance liquid chromatography triple quadrupole mass spectrometry analysis and toxicological assessment.

Polygonum multiflorum-induced liver injury (PM-DILI) has significantly hindered its clinical application and development. This study investigates the variation in content and toxicity of dianthrones, the toxic components of P. multiflorum, during different processing cycles. We employed the ultra-high-performance liquid chromatography triple quadrupole mass spectrometry method to quantify six dianthrones in raw P. multiflorum and formulations processed with a method called nine cycles of steaming and sunning. Additionally, toxicity assessments were conducted using human normal liver cell line L02 and zebrafish embryos. Results indicate a gradual reduction in dianthrones content with increasing processing cycles. Processed formulations exhibited significantly reduced cytotoxicity in L02 cells and hepatotoxicity in zebrafish embryos. Our findings elucidate the relationship between processing cycles and P. multiflorum toxicity, providing theoretical support for its safe use.

Elevated plasma level of arginine and its metabolites at labor among women with preeclampsia: A prospective cohort study.

Preeclampsia complicates 3-5% of all pregnancies and is associated with higher levels of asymmetric (ADMA) and symmetric (SDMA) dimethylarginines. Dimethylarginines are inhibitors of nitric oxide, which is a uterine smooth muscles relaxant. Women with hypertensive disorders experience a shorter labor duration compared to normotensive women. However, very little is known about the possible biochemical mechanisms behind differences in labor duration. In this study we aimed to investigate if women with preeclampsia had higher levels of arginines (ADMA, SDMA and L-arginine) at labor than controls, and also investigate the association between arginines and labor duration. The study was based on data from the Swedish, Uppsala County population-based, prospective cohort BASIC, between 2009 and 2018. Arginines were analyzed by Ultra-High Performance Liquid Chromatography using plasma samples taken at labor from women with preeclampsia (n=47) and normotensive pregnancy (n=90). We also analyzed inflammation markers CRP, TNF-R1, TNF-R2 and GDF-15. Women with preeclampsia had higher levels of ADMA (p<0.001), SDMA (p<0.001), L-arginine (p<0.001), TNF-R1 (p<0.001), TNF-R2 (p=0.03) and GDF-15 (p<0.01) compared to controls. Further, ADMA and SDMA, not inflammation markers, were negatively correlated to labor duration in preeclampsia. No correlations were observed when comparing arginines and inflammation markers. Among women with preeclampsia, our novel findings of higher level of arigines, negative correlation of arginines to duration of labor and absence of correlation of arginines to inflammation markers might support the theory that it is not inflammation but arginines which could be associated with shorter duration of labor in preeclampsia.

Discovery and Enzyme Kinetic Characterization of Novel CYP2D6 Variants.

Cytochrome P450 2D6 (CYP2D6) exhibits rich genetic polymorphism, and functional changes caused by variations are the key reasons for differences in substrate drug systemic exposure. Discovering novel variants and defining their enzymatic kinetic characteristics can contribute to the personalized application of drugs. In this study, a data chain of variant-function-structure was established through population-based sequencing, baculovirus insect cell expression, in vitro enzymatic incubation, and ultrahigh performance liquid chromatography tandem mass spectrometry. Results revealed nine novel missense mutations in the exonic regions. After the corresponding microsomes were obtained, the kinetics of the variants were investigated using dextromethorphan as a probe substrate. It was found that the activities of CYP2D6.2, 10, 17, 35, 65, R28G, T76M, and E215K were significantly reduced, while D301V almost led to loss of enzyme function. Additionally, the relative clearance rate of R25Q was significantly increased. From the molecular structure perspective, the mutation sites are distributed outside the dextromethorphan binding pocket, suggesting that they primarily influence CYP2D6 activity via allosteric modulation. These research findings provide fundamental data for the precise application of CYP2D6 substrate drugs.

Potential Antitumor Mechanism of Propolis Against Skin Squamous Cell Carcinoma A431 Cells Based on Untargeted Metabolomics.

Propolis is a sticky substance produced by honeybees (Apis mellifera) through the collection of plant resins, which they mix with secretions from their palate and wax glands. Propolis can inhibit tumor invasion and metastasis, thereby reducing the proliferation of tumor cells and inducing cell apoptosis. Previous research has shown that propolis has an inhibitory effect on skin squamous cell carcinoma A431 cells. Nevertheless, its inhibitory mechanism is unclear because of many significantly different Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between the ethanol extract of the propolis (EEP) group and the control group of cells. In this study, the main components of EEP and the antitumor mechanism at an IC50 of 29.04 μg/mL EEP were determined via untargeted metabolomics determined using ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC‒MS/MS), respectively. The results revealed 43 polyphenolic components in the EEP and 1052 metabolites, with 160 significantly upregulated and 143 significantly downregulated metabolites between cells treated with EEP and solvent. The KEGG enrichment results revealed that EEP significantly inhibited A431 cell proliferation via the steroid hormone biosynthesis and linoleic acid metabolism pathways. These findings may provide valuable insights for the development of targeted therapies for the treatment of cutaneous squamous cell carcinoma.

Molecular Characterization and Photoreactivity of Organic Aerosols Formed from Pyrolysis of Urban Materials during Fires at the Wildland-Urban Interface.

Fires at the wildland-urban interface (WUI) are increasing in magnitude and frequency, emitting organic aerosol (OA) with unknown composition and atmospheric impacts. In this study, we investigated the chemical composition of OA produced through the 600 °C pyrolysis of ten urban materials in nitrogen, which were subsequently aged under UV light for 2 h. The analysis utilized ultrahigh-performance liquid chromatography (UHPLC) separation, coupled with a photodiode array (PDA) detector and a high-resolution mass spectrometer (HRMS) for molecular characterization. Hierarchical clustering analysis demonstrated that lumber-derived OA was the most diverse and distinct in composition. Unaged and aged OA (for each urban material) did not significantly differ in chemical identities. Potential aromatic brown carbon (BrC) chromophores (based on their degree of unsaturation) constituted 13-42% of all assigned compounds. PDA chromatograms revealed multiple BrC chromophoric species that were either enhanced or degraded as a result of UV aging, providing insights into specific BrC chromophores responsible for photobleaching and photoenhancement of the overall absorption coefficient. Thirty-six BrC chromophores were identified across the ten OA types, and their structures were confirmed using reference standards. Components of plasticizers and resins, such as phthalic and terephthalic acids, were structurally confirmed in the samples. We present potential species for WUI fires as components of resins, epoxies, dyes, and adhesives commonly used in manufacturing urban materials. Photolysis did not significantly impact the chemical composition of OA emitted from the burning of specific WUI materials.

Occurrence and profiles of bisphenol A and its analogues in marine shrimps from Tianjin and their implications for human exposure

Bisphenols, a class of compounds with endocrine-disrupting characteristics, encompassing its effects on reproduction, nervous and immune systems. Diet represents the principal route of bisphenols intake, prompting concerns about dietary exposure. In this study, the occurrence and content of nine bisphenols in 96 marine shrimps from Tianjin were detected and analysed using ultra high performance liquid chromatography mass spectrometer and solid-phase extraction. The analytical method was validated to demonstrate reliable analytical performance. The results revealed that bisphenol A was detected in the majority of the samples, with the highest detection rate among the nine bisphenols, followed by bisphenol S, while the remaining bisphenols were not detected. A discernible age-related trend was identified in the assessment of dietary exposure, whereby exposure levels increased with decreasing age. Furthermore, regional discrepancies were observed, yet no gender-based distinctions were discerned. The estimated daily intake to total bisphenols through marine shrimp in this study was lower than the current tolerable daily intake set by the European Food Safety Authority, and it can be assumed that the risk of exposure to the nine bisphenols investigated through dietary is acceptable. However, given the recently proposed draft values by the European Food Safety Authority and the higher exposures observed in children and teenagers, further surveillance and dietary guidance is required. To our knowledge, this is the first study in Tianjin to evaluate the health risks associated with bisphenol A and its analogues via marine shrimp, which can monitor dietary safety and protect population health.

Comprehensive amino acids profiling: Grape varieties grown in California and in Tuscany, Italy.

Twenty-three amino acids and glutathione were profiled in 33 juices: Cabernet sauvignon, Cabernet franc, and Merlot grown in Bolgheri, Tuscany, Italy, and Napa Valley, CA, as well as Petit Verdot grown in Napa Valley, CA. The method was carried out by online pre-column derivatization followed by ultra-high performance liquid chromatography with fluorescence detection; residual standard deviation values for repeatability (n=20) were<5%. All amino acids could be successfully separated in these samples within 18 min. The most abundant amino acids, PRO, γ-aminobutyric acid, and ARG, varied by two-, two-, and three-fold, respectively, across all of the grape juices sampled. Comparisons between grape juices based on their geographic origin and variety were made with principal component analysis and hierarchical cluster analysis. Merlot juices from both regions were correlated differently by amino acids profile than Cabernet sauvignon and Cabernet franc juices. The amino acids profile in Merlot juices was more similar between most sites in Bolgheri. In contrast, Cabernet sauvignon and Cabernet franc juices had a higher similarity between vineyards in Bolgheri and vineyards in Napa Valley. Overall, most of the amino acids quantified in Cabernet franc juices and, to a lesser degree, Cabernet sauvignon juices from Bolgheri and Napa Valley vineyards were strongly correlated with each other.

Prepartum supplementation of dairy cows with inorganic selenium, organic selenium or rumen-protected choline does not affect carotenoid composition or colour characteristics of bovine colostrum or transition milk.

Minerals are supplemented routinely to dairy cows during the dry period to prevent metabolic issues postpartum. However, limited information exists on the impacts of mineral supplementation on colostrum carotenoids. This study aimed to determine the effects of prepartum supplementation with three micro-nutrients; inorganic selenium (INORG), organic selenium (ORG) or rumen-protected choline (RPC) on the carotenoid content of bovine colostrum and transition milk (TM) from pasture-based dairy cows. A total of 57 (12 primiparous and 45 multiparous) Holstein-Friesian (HF) and HF × Jersey (JEX) cows were supplemented daily for 49 ± 12.9 d before calving. Colostrum samples were collected from all cows immediately postpartum and TM one to five (TM1-TM5) were collected from a sub-set of 15 cows (five per treatment group) at each consecutive milking postpartum. Carotenoid concentration was determined using ultra-high performance liquid chromatography - diode array detection (UHPLC-DAD). With the use of transmittance, the colour index and colour parameters a*, b* and L* were used to determine colour variations over this period. Prepartum supplementation did not have a significant effect on colostrum β-carotene concentration or colour. Positive correlations between β-carotene and colour parameter b* (R2 = 0.671; P < 0.001) and β-carotene and colour index (R2 = 0.560; P < 0.001) were observed. Concentrations of β-carotene were highest in colostrum (1.34 μg/g) and decreased significantly with each milking postpartum (TM5 0.31 μg/g). Breed had a significant effect on colostrum colour with JEX animals producing a greater b* colostrum than HF animals (P = 0.030). Primiparous animals produced colostrum with the weakest colour compared to second or ≥third parity animals (P = 0.042). Despite statistical increases in the b* parameter in colostrum from JEX cows and multiparous cows, β-carotene concentrations did not significantly increase suggesting that other factors may influence colostrum colour. The b* parameter may be used as an indicator for estimating carotenoid concentrations in colostrum and TM, particularly when assessed via transmittance spectroscopy.

Antimicrobial activities of polyphenol-based metabolites present in lettuce and recent methods for their estimation

The tissue structure of fresh-cut lettuce is easy to be damaged during processing and transportation, which leads to the reduction of its edible quality and safety. Ultra-high-performance liquid chromatography (UHPLC) combined with time-of-flight tandem mass spectrometry (TMS) metabolomics was used to identify the differential metabolites related to the antibacterial activity in lettuce and explore their bacteriostatic mechanism. The experimental results revealed that the growth of Escherichia coli was quite different when different varieties of lettuce were used as the nutrient substrate. Between the varieties Beizisheng No. 3 (BZ3) and Shooter 101 (SS), 204 differential metabolites showed significant changes (P &lt; 0.05), 86 metabolites showed changes between the varieties BZ3 and Beisansheng No. 1 (BS1). Among the metabolites, isoquercitrin was the upregulated differential metabolite in BZ3 compared to SS and BS1. The content of isoquercitrin in lettuce juice positively correlated with the antibacterial activity of polyphenol extract, but negatively correlated with the growth of E. coli. The bacteriostatic property of polyphenol extract destroys the morphological structure of E. coli. The higher the isoquercitrin content, the stronger the resistance of fresh-cut lettuce to E. coli.

The Comprehensive Profiling of the Chemical Components in the Raw and Processed Roots of Scrophularia ningpoensis by Combining UPLC-Q-TOF-MS Coupled with MS/MS-Based Molecular Networking

Scrophulariae Radix (SR), the dried root of Scrophularia ningpoensis Hemsl (S. ningpoensis), has been extensively used as traditional Chinese medicine for thousands of years. However, since the mid-20th century, the traditional processing technology of S. ningpoensis has been interrupted. Therefore, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry technology, together with a Global Natural Product Social Molecular Networking (GNPS) method, was applied to comprehensively analyze the characteristic changes and mutual transformation of chemical constituents in the differently processed roots of S. ningpoensis, as well as to scientifically elucidate the processing mechanism of differently processed SR. As a result, a total of 149 components were identified. Notably, with the help of the GNPS data platform and MS2 fragment ions, the possible structures of four new compounds (47, 48, 50, and 73) were deduced in differently processed SR samples, in which 47, 48, and 50 are iridoid glycosides, and 73 is a phenylpropanoid glycoside. Five cyclopeptides (78, 86, 97, 99, and 104) derived from leucine (isoleucine) were identified in SR for the first time. The heatmaps analysis results indicated that leucine or isoleucine may be converted to cyclopeptides under the prolonged high-temperature conditions. Moreover, it is found that short-time steaming can effectively prevent the degradation of glycosides by inactivating enzymes. This study provides a new and efficient technical strategy for systematically identifying the chemical components, rapidly discovering the components, and preliminarily clarifying the processing mechanism of S. ningpoensis, as well as also providing a scientific basis for the improvement of the quality standards and field processing of S. ningpoensis.

Liquid Chromatography-Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Dalbavancin in Plasma of Pediatric and Young Adult Patients.

Dalbavancin, an antimicrobial lipoglycopeptide, is authorized in Europe for treating acute bacterial infections of the skin and skin structures in adults and pediatric patients aged 3 months and older. However, off-label dosing regimens have been proposed for various indications beyond acute bacterial infections of the skin and skin structures. This study presents a novel bioanalytical method using liquid chromatography-tandem mass spectrometry to quantify dalbavancin in low-volume plasma samples (50 μL). The method underwent validation in accordance with international guidelines for bioanalytical method validation and was applied to 9 clinical samples obtained from pediatric and young adult patients undergoing dalbavancin therapy. Liquid chromatography-tandem mass spectrometry analyses were conducted at the G. Gaslini Institute in Genoa, Italy, utilizing an Ultimate 3000 ultra high performance liquid chromatography system coupled to a TSQ Quantiva Triple Quadrupole system (Thermo Fisher Scientific, Milan, Italy). The analytical procedure involved the addition of deuterated dalbavancin as internal standard and a rapid extraction from 50 µL of human plasma, followed by chromatographic separation on a Thermo Scientific Accucore Polar Premium column. Accurate quantification of the analyte was achieved through multiple reaction monitoring detection. The assay exhibited linearity within the concentration range of 0.66-400 mcg/mL in plasma, demonstrating accuracy and reproducibility in the absence of matrix effects. Stability testing was conducted on both quality controls and real samples to establish a robust protocol under real-life conditions. This fast and reliable dalbavancin quantitation method could improve current pediatric clinical practice by enabling data collection for future dose recommendations in special patient populations.