Chromatography-electrospray Ionization-tandem Mass Spectrometry Research Articles

Comparative analysis of Chrysoporthe cubensis exoproteomes and their specificity for saccharification of sugarcane bagasse

The phytopathogenic fungus Chrysoporthe cubensis is a relevant source of lignocellulolytic enzymes. This work aimed to compare the profile of lignocellulose-degrading proteins secreted by C. cubensis grown under semi-solid state fermentation using wheat bran (WB) and sugarcane bagasse (SB). The exoproteomes of the fungus grown in wheat bran (WBE) and sugarcane bagasse (SBE) were qualitative and quantitatively analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS). Data are available via ProteomeXchange with identifier PXD046075. Label-free proteomic analysis of WBE and SBE showed that the fungus produced a spectrum of carbohydrate-active enzymes (CAZymes) with exclusive characteristics from each extract. While SBE resulted in an enzymatic profile directed towards the depolymerization of cellulose, the enzymes in WBE were more adaptable to the degradation of biomass rich in hemicellulose and other non-lignocellulosic polymers. Saccharification of alkaline pre-treated sugarcane bagasse with SBE promoted glucose release higher than commercial cocktails (8.11 g L−1), while WBE promoted the higher release of xylose (5.71 g L−1). Our results allowed an in-depth knowledge of the complex set of enzymes secreted by C. cubensis responsible for its high lignocellulolytic activity and still provided the identification of promising target proteins for biotechnological applications in the context of biorefinery.

Analyzing antibiotic residues in honey samples using liquid chromatography-tandem mass spectrometry

ABSTRACT This study aimed to present a sensitive, accurate, and precise analytical method for the determination of 32 antibiotics from 5 groups (sulfonamides, macrolides, aminoglycosides, tetracyclines, and quinolones) and some individual antibiotics (lincomycin, griseofulvin, and 5-hydroxy-flunixin) in 63 honey samples collected from Tehran market. In the presented method, the samples were hydrolyzed by 1% HFBA (hepta fluoro butyric acid) in water, purified on Strata XL polymeric reversed-phase cartridges, and finally analyzed by reversed-phase ion-pair liquid chromatography-electrospray ionization tandem mass spectrometry (RP-IP-LC-ESI-MS/MS). Good performance characteristics were gained for recovery, precision, range, and linearity, the limit of detections (LODs), and the limit of quantifications (LOQs). According to the presented results and considering the absence of permissible limits for antibiotics in honey, 74.6% of the tested samples had antibiotic residues more than the LOQ of the method. The results show that the validated method is suitable for simultaneously detecting antibiotic residues in honey.

ITRAQ-based proteomics reveals potential markers and treatment pathways for acute Achilles tendon rupture

BackgroundDue to its limited blood supply and irregular mechanical loading, the Achilles tendon is the most frequently ruptured tendon. Despite the rising incidence of acute Achilles tendon rupture (AATR), the optimal treatment remains controversial. Missed diagnoses and delayed treatments lead to poor outcomes and limited treatment options. This study aimed to identify potential biomarkers for diagnosing and developing therapies for AATR.MethodsWe employed the coupled isobaric tag for relative and absolute quantitation-liquid chromatography–electrospray ionization-tandem mass spectrometry approach to investigate protein expression in tissues from AATR patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to identify differentially expressed proteins (DEPs) between AATR patients and healthy individuals. A protein–protein interaction (PPI) network of DEPs was constructed using the Search Tool for the Retrieval of Interacting Genes. The screened hub genes were selectively verified by immunohistochemical staining.ResultsWe identified 410 DEPs between AATR patients and controls. The DEPs were significantly enriched in GO terms such as the extracellular region, extracellular region part, and defense response, as well as KEGG pathways, including complement and coagulation cascades, focal adhesion, and regulation of actin cytoskeleton. The main hub nodes in the PPI network comprised fibronectin 1 (FN1), major histocompatibility complex, class I, B (HLA-B), filamin A (FLNA), heat shock 27-kDa protein 1 (HSPB1), heat shock protein family A member 5 (HSPA5), apolipoprotein A4 (APOA4), and myosin IC (MYO1C). Although APOA4 and collagens I, II, and III were detectable in healthy tendons, immunohistochemical staining confirmed higher expression of these proteins in the acutely ruptured Achilles tendon.ConclusionsOur findings lay a foundation for further molecular studies of AATR. Inflammation and age-related degeneration may contribute to the pathogenesis of AATR. Moreover, the identified DEPs could be potential biomarkers for AATR diagnosis and treatment.

Functional Characterization of AP2/ERF Transcription Factors during Flower Development and Anthocyanin Biosynthesis Related Candidate Genes in Lycoris.

The APETALA2/ethylene-responsive transcription factor (AP2/ERF) family has been extensively investigated because of its significant involvement in plant development, growth, fruit ripening, metabolism, and plant stress responses. To date, there has been little investigation into how the AP2/ERF genes influence flower formation and anthocyanin biosynthesis in Lycoris. Herein, 80 putative LrAP2/ERF transcription factors (TFs) with complete open reading frames (ORFs) were retrieved from the Lycoris transcriptome sequence data, which could be divided into five subfamilies dependent on their complete protein sequences. Furthermore, our findings demonstrated that genes belonging to the same subfamily had structural similarities and conserved motifs. LrAP2/ERF genes were analyzed for playing an important role in plant growth, water deprivation, and flower formation by means of gene ontology (GO) enrichment analysis. The expression pattern of the LrAP2/ERF genes differed across tissues and might be important for Lycoris growth and flower development. In response to methyl jasmonate (MeJA) exposure and drought stress, the expression of each LrAP2/ERF gene varied across tissues and time. Moreover, a total of 20 anthocyanin components were characterized using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis, and pelargonidin-3-O-glucoside-5-O-arabinoside was identified as the major anthocyanin aglycone responsible for the coloration of the red petals in Lycoris. In addition, we mapped the relationships between genes and metabolites and found that LrAP2/ERF16 is strongly linked to pelargonidin accumulation in Lycoris petals. These findings provide the basic conceptual groundwork for future research into the molecular underpinnings and regulation mechanisms of AP2/ERF TFs in anthocyanin accumulation and Lycoris floral development.

Dose-response formation of N7-(3-benzo[1,3]dioxol-5-yl-2-hydroxypropyl)guanine in liver and urine correlates with micronucleated reticulocyte frequencies in mice administered safrole oxide

Safrole oxide (SAFO), a metabolite of naturally occurring hepatocarcinogen safrole, is implicated in causing DNA adduct formation. Our previous study first detected the most abundant SAFO-induced DNA adduct, N7-(3-benzo[1,3] dioxol-5-yl-2-hydroxypropyl)guanine (N7γ-SAFO-G), in mouse urine using a well-developed isotope-dilution high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (ID-HPLC-ESI-MS/MS) method. This study further elucidated the genotoxic mode of action of SAFO in mice treated with SAFO 30, 60, 90, or 120 mg/kg for 28 days. The ID-HPLC-ESI-MS/MS method detected N7γ-SAFO-G with excellent sensitivity and specificity in mouse liver and urine of SAFO-treated mice. Our data provide the first direct evidence of SAFO-DNA adduct formation in rodent tissues. N7γ-SAFO-G levels in liver were significantly increased by SAFO 120 mg/kg compared with SAFO 30 mg/kg, suggesting rapid spontaneous or enzymatic depurination of N7γ-SAFO-G in tissue DNA. Urinary N7γ-SAFO-G exhibited a sublinear dose response. Moreover, the micronucleated peripheral reticulocyte frequencies increased dose-dependently and significantly correlated with N7γ-SAFO-G levels in liver (r = 0.8647; p < 0.0001) and urine (r = 0.846; p < 0.0001). Our study suggests that safrole-mediated genotoxicity may be caused partly by its metabolic activation to SAFO and that urinary N7γ-SAFO-G may serve as a chemically-specific cancer risk biomarker for safrole exposure.

Identification of Novel Glycans in the Mucus Layer of Shark and Skate Skin.

The mucus layer covering the skin of fish has several roles, including protection against pathogens and mechanical damage. While the mucus layers of various bony fish species have been investigated, the composition and glycan profiles of shark skin mucus remain relatively unexplored. In this pilot study, we aimed to explore the structure and composition of shark skin mucus through histological analysis and glycan profiling. Histological examination of skin samples from Atlantic spiny dogfish (Squalus acanthias) sharks and chain catsharks (Scyliorhinus retifer) revealed distinct mucin-producing cells and a mucus layer, indicating the presence of a functional mucus layer similar to bony fish mucus albeit thinner. Glycan profiling using liquid chromatography-electrospray ionization tandem mass spectrometry unveiled a diverse repertoire of mostly O-glycans in the mucus of the two sharks as well as little skate (Leucoraja erinacea). Elasmobranch glycans differ significantly from bony fish, especially in being more sulfated, and some bear resemblance to human glycans, such as gastric mucin O-glycans and H blood group-type glycans. This study contributes to the concept of shark skin having unique properties and provides a foundation for further research into the functional roles and potential biomedical implications of shark skin mucus glycans.

Rapid and simple identification of trace amounts of sodium azide in beverages and bodily fluids followed by derivatization and liquid chromatography-electrospray ionization tandem mass spectrometry.

Sodium azide (NaN3 ) is a toxic chemical agent to humans by ingestion and inhalation with a growing number of intentional exposures and accidental cases over the last few decades. Due to its low molecular weight and lack of any chromophore, its retention and detection by reverse-phase liquid chromatography-ultraviolet-mass spectrometry methods are a challenging task. To be able to confirm azide exposure, we have developed a method to identify azide in both beverages and bodily fluids. The identification of azide (N3 - ) is based on derivatization with N-(2-(bromomethyl)benzyl)-N,N-diethylethanaminium bromide (CAX-B) at 25°C for 15 min followed by LC/ESI-MS/MS analysis, with no other sample preparation. The azide after derivatization (CAX-N3 ) was stable, retainable by LC and sensitively detected by selected reaction monitoring. The ESI-MS/MS fragmentation of the M+ precursor ion produced characteristic product ions at m/z 118, 100, 91 and 86. The calibration curves for CAX-N3 showed linearity over two orders of magnitude with R2 value of 0.99. Low limits of identification of 0.1-0.5ng/mL were obtained in all investigated matrices (drinking water, tea, orange juice, plasma and urine). Compared with previously reported chromatography-based methods, this method that was based on derivatization and LC/ESI-MS/MS analysis was substantially more sensitive, simpler and faster. The method can be used for forensic investigation to confirm azide exposure from fatal use to much smaller intoxication dose.

Untargeted polysulfide omics analysis of alternations in polysulfide production during the germination of broccoli sprouts

Higher consumption of broccoli (Brassica oleracea var. italica) is associated with a reduced risk of cardiometabolic diseases, neurological disorders, diabetes, and cancer. Broccoli is rich in various phytochemicals, including glucosinolates, and isothiocyanates. Moreover, it has recently reported the endogenous production of polysulfides, such as cysteine hydropersulfide (CysS2H) and glutathione hydropersulfide (GS2H), in mammals including humans, and that these bioactive substances function as potent antioxidants and important regulators of redox signaling in vivo. However, few studies have focused on the endogenous polysulfide content of broccoli and the impact of germination on the polysulfide content and composition in broccoli. In this study, we investigated the alternations in polysulfide biosynthesis in broccoli during germination by performing untargeted polysulfide omics analysis and quantitative targeted polysulfide metabolomics through liquid chromatography–electrospray ionization–tandem mass spectrometry. We also performed 2,2-diphenyl-1-picrylhydrazyl radical–scavenging assay to determine the antioxidant properties of the polysulfides. The results revealed that the total polysulfide content of broccoli sprouts significantly increased during germination and growth; CysS2H and cysteine hydrotrisulfide were the predominant organic polysulfide metabolites. Furthermore, we determined that novel sulforaphane (SFN) derivatives conjugated with CysS2H and GS2H were endogenously produced in the broccoli sprouts, and the novel SFN conjugated with CysS2H exhibited a greater radical scavenging capacity than SFN and cysteine. These results suggest that the abundance of polysulfides in broccoli sprouts contribute to their health-promoting properties. Our findings have important biological implications for the development of novel pharmacological targets for the health-promoting effects of broccoli sprouts in humans.

Dietary risk assessment of benzophenone derivatives using bread consumption estimates in a Taiwanese population.

Listed as endocrine-disrupting chemicals, benzophenone (BP) and its nine analogues (BPs) are an emerging group of contaminants. The migration of BPs from ultraviolet inks to food has been investigated in many studies; however, few studies have investigated BPs in foods and the risks of human exposure to BPs. We validated a trace and multi-residue method for simultaneously determining 10 BPs, including BP, BP-1, BP-2, BP-3, BP-8, 4-MBP, 2-OHBP, 4-OHBP, M2BB, and PBZ. Eighty-one bread samples were analyzed using stable isotope labeling and ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with solid-liquid extraction. We determined the estimated daily intake of BPs, non-cancer risks, and lifetime cancer risks (LTCRs) from daily bread consumption for seven age groups using a Monte Carlo simulation. The method demonstrated robust linearity (R2 ≥ 0.991), low limits of detection (0.04-2 ng/g), and satisfactory precision. The intra- and interday relative standard deviation ranges were 0.6%-9% and 3%-20%, respectively. BP, 4-MBP, 2-OHBP, BP-1, and BP-3 were detected in 97%, 67%, 59%, 24%, and 23% of the samples, respectively. 2-OHBP had the highest mean (range) value of 18.3 (<LOD-201.6) ng/g. The results demonstrated that the 0-3 year group had the highest LTCRs (2.6 × 10-6) and hazard indices [HIs] (5.4 × 10-2). The LTCRs were lower than 10-5, and the HIs were lower than 1 in seven age groups. This suggests that exposure to BPs from bread consumption is safe and acceptable.

Antrodia salmonea suppresses epithelial-mesenchymal transition/metastasis and Warburg effects by inhibiting Twist and HIF-1α expression in Twist-overexpressing head and neck squamous cell carcinoma cells

Ethnopharmacological relevanceAntrodia salmonea (AS), linked to the genus Taiwanofungus, is a medicinal fungus, and exhibits anti-inflammatory, anti-oxidant, and tumor inhibiting properties. Aim of the studyIn this study, we investigated the metabolic reprogramming and anti-metastasis/epithelial-mesenchymal transition (EMT) effects of AS exposure in Twist-overexpressing head and neck squamous cell carcinoma (HNSCC, OECM-1 and FaDu-Twist) cells. Materials and methodsMTT assay, Western blot, migration/invasion assay, immunofluorescence, glucose uptake assay, lactate assay, oxygen consumption rate (OCR)/Extracellular acidification rate (ECAR) assay, Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS), and qRT-PCR experimental techniques were used to evaluate the therapeutic potential of AS treatment in HNSCC cells. ResultsThis study showed that AS exhibits anti-EMT and anti-metastatic effects as well as metabolic reprogramming in Twist-overexpressing HNSCC cells. AS exposure inhibited Twist and hypoxia-inducible factor-1α (HIF-1α) protein and/or mRNA expression in Twist-overexpressing OECM-1 and FaDu-Twist cells. AS markedly suppressed EMT by enhancing the expression of E-cadherin; while the N-cadherin was suppressed. Furthermore, glucose uptake and lactate accumulation, together with HIF-1α-regulated glycolysis genes were diminished by AS in OECM-1 cells. AS decreased the ECAR, and enhanced the OCR together with basal respiration, ATP production, maximal respiration, and spare respiratory capacity under normoxia and hypoxia (CoCl2) in OECM-1 cells. There was a marked reduction in the level of glycolytic intermediate's; while TCA cycle metabolites were increased by AS treatment in OECM-1 cells. ConclusionsWe concluded that AS treatment suppresses EMT/metastasis and Warburg effects through Twist and HIF-1α inhibition in Twist-overexpressing HNSCC cells.

A pharmacokinetic study to correlate the hypoglycemic effect of phlorizin in rats: Identification of metabolites as inhibitors of sodium/glucose cotransporters.

Phlorizin (PRZ) is a natural product that belongs to a class of dihydrochalcones. The unique pharmacological property of PRZ is to block glucose absorption or reabsorption through specific and competitive inhibitors of the sodium/glucose cotransporters (SGLTs) in the intestine (SGLT1) and kidney (SGLT2). This results in glycosuria by inhibiting renal reabsorption of glucose and can be used as an adjuvant treatment for type 2 diabetes. The pharmacokinetic profile, metabolites of the PRZ, and efficacy of metabolites towards SGLTs are unknown. Therefore, the present study on the characterization of hitherto unknown in vivo metabolites of PRZ and pharmacokinetic profiling using liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) and accurate mass measurements is undertaken. Plasma, urine, and feces samples were collected after oral administration of PRZ to Sprague-Dawley rats to identify in vivo metabolites. Furthermore, in silico efficacy of the identified metabolites was evaluated by docking study. PRZ at an intraperitoneal dose of 400 mg/kg showed maximum concentration in the blood to 439.32 ± 8.84 ng/mL at 1 h, while phloretin showed 14.38 ± 0.33 ng/mL at 6 h. The pharmacokinetic profile of PRZ showed that the maximum concentration lies between 1 and 2 h after dosing. Decreased blood glucose levels and maximum excretion of glucose in the urine were observed when the PRZ and metabolites were observed in plasma. The identification and characterization of PRZ metabolites by LC/ESI/MS/MS further revealed that the phase I metabolites of PRZ are hydroxy (mono-, di-, and tri-) and reduction. Phase II metabolites are O-methylated, O-acetylated, O-sulfated, and glucuronide metabolites of PRZ. Further docking study revealed that the metabolites diglucuronide metabolite of mono-hydroxylated PRZ and mono-glucuronidation of PRZ could be considered novel inhibitors of SGLT1 and SGLT2, respectively, which show better binding affinities than their parent compound PRZ and the known inhibitors.

Profound Diversity of the N-Glycome from Microdissected Regions of Colorectal Cancer, Stroma, and Normal Colon Mucosa

• Striking diversity of N -glycosylation was found between cancerous, stromal and healthy mucosa cells. • Cancer showed increased α2-6 sialylation and monoantennary N -glycans and decreased bisection compared to healthy mucosa. • N -glycans carrying (sialyl-)Lewis A/X were exclusively found in cancer. • Stroma showed higher fucosylation and (α2-3) sialylation and lower oligomannosidics, monoantennaries, Lewis A/X and sulfation compared to cancer. Aberrant glycosylation is considered to be a hallmark of colorectal cancer (CRC), as demonstrated by various studies. While the N -glycosylation of cell lines and serum has been widely examined, the analysis of cancer-associated N -glycans from tissues has been hampered by the heterogeneity of tumors and the complexity of N -glycan structures. To overcome these obstacles, we present a study using laser capture microdissection that makes it possible to largely deconvolute distinct N- glycomic signatures originating from different regions of heterogeneous tissues including cancerous, stromal, and healthy mucosa cells. N -glycan alditols were analyzed by means of porous graphitized carbon liquid chromatography-electrospray ionization tandem mass spectrometry, enabling the differentiation and structural characterization of isomeric species. In total, 116 N- glycans were identified that showed profound differences in expression among cancer, stroma, and normal mucosa. In comparison with healthy mucosa, the cancer cells showed an increase in α2-6 sialylation and monoantennary N -glycans, as well as a decrease in bisected N -glycans. Moreover, specific sialylated and (sialyl-)Lewis A/X antigen-carrying N -glycans were exclusively expressed in cancers. In comparison with cancer, the stroma showed lower levels of oligomannosidic and monoantennary N -glycans, Lewis A/X epitopes, and sulfation, as well as increased expression of (core-)fucosylation and α2-3 sialylation. Our study reveals the distinct N -glycomic profiles of different cell types in CRC tumor and control tissues, proving the necessity of their separate analysis for the discovery of cancer-associated glycans.

Mineral composition, principal polyphenolic components, and evaluation of the anti-inflammatory, analgesic, and antioxidant properties of Cytisus villosus Pourr leaf extracts

Abstract Cytisus villosus Pourr. (C. villosus) is a medicinal plant belonging to the Fabaceae family, which grows in the Mediterranean area. It is used in traditional medicine against diseases related to inflammation. The objective of the present study was to identify the mineral and polyphenolic composition as well as to evaluate some biological properties including antioxidant, anti-inflammatory, and analgesic activities of C. villosus leaf aqueous extract. The chemical constituents were identified and quantified using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) methods. The antioxidant properties of C. villosus leaves were tested using reducing power (RP), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) assays. The anti-inflammatory potency was evaluated in vitro and in vivo using the albumin denaturation test and the carrageenan test, respectively. Furthermore, the analgesic effect was performed in vivo using tail flick, acetic acid-induced contortion, and plantar tests. Mineralogical analysis revealed that potassium and calcium were the most abundant minerals. The analysis and quantification of the phytochemical composition using UPLC-ESI-MS/MS showed that quinic acid (57.478 ± 1.72 mg/kg) was the major compound of the aqueous extract, followed by salicylic acid (17.38 ± 0.2 mg/kg), isoquercetin (16.895 ± 1.01 mg/kg), and gallic acid (15.914 ± 1.51 mg/kg). The extracts showed potent antioxidant activity for all tests used. The highest antioxidant activity was recorded for the DPPH, ABTS and RP methods, with an IC50 of 3.94 ± 0.09, 2.88 ± 0.07, and 1.94 ± 0.10 μg/mL, respectively. Additionally, using the most frequent analgesic assays, the aqueous extract at a dose of 500 mg/kg exhibited a potent analgesic activity. Notably, an interesting inhibition of albumin denaturation was recorded with an IC50 of 383.94 μg/mL, corroborating the in vivo test. Overall, the results presented here may represent a scientific basis for the traditional use of C. villosus in the treatment of inflammation-related diseases.

Abscisic Acid: A Potential Secreted Effector Synthesized by Phytophagous Insects for Host-Plant Manipulation.

Abscisic acid (ABA) is an isoprenoid-derived plant signaling molecule involved in a wide variety of plant processes, including facets of growth and development as well as responses to abiotic and biotic stress. ABA had previously been reported in a wide variety of animals, including insects and humans. We used high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-(ESI)-MS/MS) to examine concentrations of ABA in 17 species of phytophagous insects, including gall- and non-gall-inducing species from all insect orders with species known to induce plant galls: Thysanoptera, Hemiptera, Lepidoptera, Coleoptera, Diptera, and Hymenoptera. We found ABA in insect species in all six orders, in both gall-inducing and non-gall-inducing species, with no tendency for gall-inducing insects to have higher concentrations. The concentrations of ABA in insects often markedly exceeded those typically found in plants, suggesting it is highly improbable that insects obtain all their ABA from their host plant via consumption and sequestration. As a follow-up, we used immunohistochemistry to determine that ABA localizes to the salivary glands in the larvae of the gall-inducing Eurosta solidaginis (Diptera: Tephritidae). The high concentrations of ABA, combined with its localization to salivary glands, suggest that insects are synthesizing and secreting ABA to manipulate their host plants. The pervasiveness of ABA among both gall- and non-gall-inducing insects and our current knowledge of the role of ABA in plant processes suggest that insects are using ABA to manipulate source-sink mechanisms of nutrient allocation or to suppress host-plant defenses. ABA joins the triumvirate of phytohormones, along with cytokinins (CKs) and indole-3-acetic acid (IAA), that are abundant, widespread, and localized to glandular organs in insects and used to manipulate host plants.

Catalytic behavior of nitrous acid for acetaminophen transformation during the freezing process

This study demonstrates the transformation of acetaminophen by reactive nitrous acid in a frozen solution and its abnormal stoichiometry. The chemical reaction between acetaminophen and nitrous acid (AAP/NO2− system) was negligible in the aqueous solution; however, the reaction rapidly progressed if the solution started to freeze. The ultrahigh performance liquid chromatography–electrospray ionization tandem mass spectrometry measurements showed that polymerized acetaminophen and nitrated acetaminophen were formed in the proceeding reaction. Electron paramagnetic resonance spectroscopy measurements showed that nitrous acid oxidized acetaminophen via a one-electron transfer reaction producing acetaminophen-derived radical species, which is the cause of acetaminophen polymerization. We demonstrated that a relatively smaller dose of nitrite than acetaminophen caused significant acetaminophen degradation in the frozen AAP/NO2− system and revealed that the dissolved oxygen content notably affected acetaminophen degradation. We showed that the reaction occurs in a natural Arctic lake matrix (nitrite and acetaminophen spiked). Considering that the freezing phenomenon is common in the natural environment, our research provides a possible scenario for the freezing chemistry of nitrite and pharmaceuticals in environmental chemistry.

Natural Occurrence of Alternaria Toxins in Citrus-Based Products Collected from China in 2021.

A total of 181 citrus-based products, including dried fruits, canned fruits, and fruit juices, collected from China and from abroad in 2021 were analyzed for the four Alternaria toxins (ALTs): alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), and tenuazonic acid (TeA) via ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS). Although the concentrations of the four ALTs varied by product and geographically, TeA was the predominant toxin followed by AOH, AME, and TEN. Products made in China showed higher levels of ALTs than those made abroad. Maximum levels of TeA, AOH, and AME in analyzed domestic samples were 4.9-fold, 1.3-fold, and 1.2-fold, respectively, higher than those in imported products. Furthermore, 83.4% (151/181) of the analyzed citrus-based products were contaminated with at least two or more ALTs. There were significant positive correlations between AOH and AME, AME and TeA, and TeA and TEN in all analyzed samples. More importantly, the solid and the condensed liquid products had higher concentrations of ALTs than the semi-solid product samples, as well as tangerines, pummelos, and grapefruits compared to the other kinds of citrus-based products. In conclusion, co-contamination with ALTs in commercially available Chinese citrus-based products was universal. Extensive and systematic surveillance of ALTs in citrus-based products, both domestic and imported, is required to obtain more scientific data for the determination of the maximum allowable concentrations of ALTs in China.

Effect of in vitro Simulated Poultry Digestion on Bioaccessibility of Quercetin 3-D-galactoside and Antioxidants from Moringa oleifera Leaf Extracts

The use of Moringa oleifera leaves as a poultry feed has been recognized worldwide, thanks to its multi-beneficial properties for broiler quality and production. However, research on the absorption and bioaccessibility of antioxidant compounds in this material is still limited. This study aims to investigate the effect of simulated poultry digestion on the bioaccessibility of quercetin 3-D-galactoside (Q3G) from Moringa leaf extracts and its antioxidant capacity via an in vitro model. Initially, a bio-guided fractionation procedure was employed to isolate Q3G and co-occurring antioxidants from Moringa leaves using column chromatography. The identification of Q3G and major phytocompounds within the potent active samples was carried out using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/ MS). The findings revealed that Q3G is predominantly present in the ethyl acetate extract of Moringa leaves, with the highest concentration recorded as 1.3 mg/g of dry weight. Via a simulated poultry digestion model, the bioaccessibility of Q3G in the small intestinal stage was calculated to have the highest proportion of 67.1%. Significantly, the change in Q3G content was in accordance with the tendency for antioxidant activity of the Q3G-included fractions throughout the digestion. The correlation analysis suggested that Q3G has an important role in the antioxidant capacity of Moringa leaf extracts. To the best of our knowledge, this study represents a pioneering attempt to investigate the bioaccessibility and antioxidant activity of Q3G and Q3G-included extracts from Moringa leaves, utilizing an in vitro poultry digestion model. The findings establish a crucial foundation for future research and development endeavors that aim to produce antioxidant supplements enriched with Q3G from natural sources for applications in poultry production.

Lipidomics of Sannen goat milk subjected to pasteurization and spray drying based on LC-ESI-MS/MS

The purpose of this study was to evaluate the effects of pasteurization and spray drying on goat milk lipids by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and multiple variable statistics. A total of 1061 lipids assigned to 29 subclasses in raw and thermal-treated groups were identified. One hundred and 85 different lipids (DLs) (VIP ≥ 1 and |Log2FC| ≥ 1.0) were selected from pairwise comparisons of goat milk by different treatments. Glycerophospholipids were the most affected subclasses by thermal processes, especially by spray drying. Five potential lipid markers [(DG (16:1_18:0), TG (18:1_22:1_18:2), Cer (t17:2/31:0), LPC (0:0/20:0), and LPS (20:0/0:0] were used to distinguish different treated goat milk. Moreover, glycerophospholipid metabolism was the primary pathway of DLs. These results would provide more details of lipid profiles in thermally treated (pasteurization and spray drying) goat milk.

Effect of homogenization on lipid profiling in Saanen goat milk based on UHPLC-QTOF-MS lipidomics

Homogenization might change the lipid composition of goat milk. This study aimed to investigate the lipid profiles, and identify different lipids (DLs) of raw goat milk (RGM) and homogenized goat milk (HGM) using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and multivariate statistics. Fifty-six DLs (VIP ≥ 1 and |Log2FC| ≥ 1.0) were identified from 1057 lipids assigned to 29 subclasses in RGM and HGM. Notably, there were many phosphatidylcholines (PCs) decreased after homogenization, while lysophosphatidylcholines (LPCs) were opposite. Our results provide more details on the impact of homogenization on goat milk lipids.

Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry Estimation of Quercetin-Loaded Nanoemulsion in Rabbit Plasma: In Vivo-In Silico Pharmacokinetic Analysis Using GastroPlus.

In the present study, we developed and validated a rapid, specific, sensitive, and reproducible liquid chromatography-electrospray ionization tandem mass spectrometry method for quantifying quercetin (QT) in rabbit plasma using hydrochlorothiazide as the internal standard. Animals were orally administered with optimized QT-loaded nanoemulsion (QTNE) and QT suspension (QTS), equivalent to 30 mg/kg, to the test and control group, respectively. The blood samples were collected at pre-determined time points up to 48 h. The linearity range was from 5 to 5000 ng mL-1 with R 2 = 0.995. Further, we analyzed the various pharmacokinetic parameters and established the in vitro-in vivo correlation (IVIVC) of QTNE using GastroPlus software. The method was successfully developed and validated, and when applied for the determination of QT in rabbit plasma, it exhibited an increase in C max from 122.56 ng mL-1 (QTS) to 286.51 ng mL-1 (QTNE) (2.34-fold) and AUC0-48 from 976 ng h mL-1 (QTS) to 4249 ng h mL-1 (QTNE) (4.35-fold), indicating improved oral bioavailability QT when administered as QTNE. Statistical analysis revealed that the Loo-Riegelman method (two-compartmental method) best fitted the deconvolution approach (R 2 = 0.998, SEP = 4.537, MAE = 2.759, and AIC = 42.38) for establishing the IVIVC. In conclusion, the established bioanalytical method and IVIVC studies revealed that QTNE is a potential carrier for the effective delivery of QT with enhanced oral bioavailability.