Liquid Chromatography-tandem Mass Spectrometry Research Articles

Dissipation Kinetics of Trinexapac Acid in Paddy Leaves, Grain, Straw and Soil Using Liquid Chromatography Tandem Mass Spectrometry.

Field experiments were conducted to investigate the dissipation and persistence residues of trinexapac acid in paddy crop. The treatments consisted of one control and two different concentrations of Trinexapac-ethyl 25% EC (Emulsifiable concentrate) at 30 and 60g a.i. ha- 1(recommended and double the recommended dose). Leaf samples were collected at random in each plot separately at 0, 1, 3, 5, 7, 10 and 15 days after foliar application and grain, straw and soil samples were collected at harvest. The mean recovery of trinexapac acid (@ 0.01, 0.05 and 0.1mg kg- 1 was more than 75%. At application rate of 30 and 60g a.i. ha- 1 (gram of active ingredient per hectare), initial trinexapac acid residues on leaves were 0.29 and 0.44mg kg- 1, respectively. Residues were observed even after 15 days of spray. At harvest time, the residues of trinexapac acid in grains were below LOQ (limit of quantification) at 30g a.i. ha- 1 treatment whereas, at 60g a.i.ha- 1, the residues were found to be 0.02mg kg- 1. In straw, trinexapac acid residues were detected to be 0.05 and 0.08mg kg- 1 at 30 and 60g a.i. ha- 1 treatments, respectively. The soil samples showed 0.04 and 0.08mg kg- 1 residue at 30 and 60g a.i. ha- 1, respectively. The half life calculated for trinexapac acid came to be 10.10 and 9.09 days revealed the slow dissipation of trinexapac acid in paddy crop. The residue of trinexapac acid reached below LOQ at harvest time. Therefore the recommend dose of trinexapac ethyl is considered safe from consumption point of view.

Plasma arginine as a predictive biomarker for outcomes with immune checkpoint inhibition in metastatic colorectal cancer: a correlative analysis of the CCTG CO.26 trial

BackgroundNutritional stress is a mechanism that allows tumor cells to evade the immune system. Arginine (ARG), an amino acid involved in immunomodulation, aids in regulating T-lymphocyte cell activity and the...

Nicotinamide mononucleotide suppresses cellular senescence and increases aquaporin 5 expression in the submandibular gland of aged male mice to ameliorate aging-related dry mouth.

Dry mouth results from decreased saliva secretion due to aging or drug side effects. Decreased saliva secretion causes dryness in the oral cavity that makes swallowing difficult and increases the risk of aspiration pneumonia. There are few fundamental treatments for dry mouth. Here we investigated whether treatment of old mice with nicotinamide mononucleotide (NMN) improved factors associated with dry mouth. Young (16-week-old) and old (113-week-old) male mice were treated subcutaneously with saline or NMN (300mg/kg) once every two days for four weeks and saliva secretion was measured. The amount of nicotinamide adenine dinucleotide (NAD+) in salivary gland tissues was measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene expression in the intestinal tract and salivary glands was measured by real-time PCR. The population of cells with acetylation in the submandibular gland was quantified by immunohistological staining. SA-β-gal activity in the submandibular gland was measured to assess cell senescence. Statistical analysis was performed by one-way analysis of variance with Tukey post hoc analysis. The submandibular glands from old mice treated with NMN exhibited increased saliva secretion and NAD+ levels, which both decrease with aging. In addition, the submandibular glands from NMN-treated old mice had decreased acetylation, numbers of senescent cells, and levels of senescence-associated secretory phenotype (SASP) factors, which all increase with aging, as well as increased aquaporin5 (AQP5) mRNA expression. NMN administration may improve dry mouth by regulating cellular senescence in the submandibular gland and increasing expression of AQP5, a water channel involved in saliva secretion, to inhibit age-related decreases in saliva secretion. It is necessary to elucidate further mechanism and confirm its effectiveness in humans.

LC–MS-based quantitation of proteomic changes induced by Norcantharidin in MTB-Treated macrophages

Tuberculosis drug resistance contributes to the spread of tuberculosis. Immunotherapy is an effective strategy for treating tuberculosis, with the regulation of macrophage-mediated anti-tuberculosis immunity being crucial. Norcantharidin (NCTD), a drug used in tumor immunotherapy, has significant immunomodulatory effects. Thus, NCTD may have an anti-tuberculosis role by regulating immunity. Understanding how NCTD affects the proteome of Mtb-infected macrophages can provide valuable insights into potential treatments. This study aimed to investigate the impact of NCTD (10 μg/mL) on the proteome of macrophages infected with Mtb H37Ra using liquid chromatography-tandem mass spectrometry (LC–MS/MS) analysis. A total of 69 differentially regulated proteins (DRPs) were identified, with 28 up-regulated and 41 down-regulated in the NCTD-treated group. Validation of six DRPs (CLTCL1, VAV1, SP1, TRIM24, MYO1G, and WDR70) by Western blot analysis confirmed the accuracy of the LC–MS/MS method used in this study. NCTD modulates various protein expressions involved in chromatin-modifying enzymes, RHO GTPases activating PAKs, Fc gamma R-mediated phagocytosis, T cell receptor signaling pathway, and antigen processing and presentation. Overall, the research provides new insights into the effects of NCTD on the proteome of Mtb-infected macrophages. The identified changes highlight potential targets for future therapeutic interventions aimed at enhancing host immunity against Mtb infection or developing new anti-TB drugs based on these findings.

Clinical spectrum and genetic variation of six patients with methylmalonic aciduria (MMA); a report from Iran

ObjectiveMethylmalonic acidemia (MMAs) is known as a severe, complex, and lethal disorder of methylmalonate and cobalamin. The patients with MMA may have developmental, neurological, and metabolic disorders such as liver disease. Here, we aim to evaluate 6 Iranian patients suspected to MMA disorder.Study designWe will provide genetic results, biochemical analysis and treatment for these patients. Liquid chromatography-tandem mass spectrometry (LC–MS/MS) and variant screening in probands by whole exome sequencing (WES) were performed.ResultsA total of six homozygous variants were identified, including five previously identified variants and one novel variant, in the two MMA-causing genes as follows: c.577G > C, c.290 + 69G > T, c.662T > A, c.290 + 69G > T of MMAB, and c.100dupA, c.394 C > T of MMACHC. Sanger sequencing confirmed the identified variants. Additionally, metabolomics data analysis reliably identified elevated C3 and MMA levels, as well as abnormalities in the amino acid profile, indicating the presence of pathogenic variants.ConclusionsOur findings expand the global spectrum of genotypes in MMA. While WES, combined with metabolomics and biochemical analysis, offers valuable insights for accurate diagnosis and subtyping of MMA, it is most beneficial in complex cases where clinical findings are unclear.

The association of vitamin D with knee osteoarthritis pain: an analysis from the Osteoarthritis Initiative database

Knee osteoarthritis (KOA) is a major cause of disability in the elderly, with its pain primarily driving medical consultations. Despite numerous studies, the role of Vitamin D in managing KOA pain remains inconclusive. This study seeks to explore the association between serum Vitamin D levels and WOMAC pain scores, providing new insights into potential treatment strategies for KOA. Utilizing data from the Osteoarthritis Initiative (OAI) database, we conducted a cross-sectional analysis involving 524 participants. Serum levels of 25-hydroxyvitamin D were measured using liquid chromatography-tandem mass spectrometry. WOMAC pain scores served as the dependent variable. Multivariable linear regression models and restricted cubic splines were employed to assess the relationship between Vitamin D levels and KOA pain, with subgroup analyses stratified by sex. Higher Vitamin D levels were significantly associated with lower WOMAC pain scores in males across all models. For females, no significant associations were observed. The analysis suggests a nonlinear relationship between Vitamin D levels and KOA pain in the general cohort, which becomes non-significant after adjustment for covariates. Our findings indicate that Vitamin D is associated with reduced pain in male patients with KOA, highlighting a potential sex-specific therapeutic approach. The results warrant further investigation through longitudinal studies and randomized controlled trials to substantiate Vitamin D supplementation as a viable treatment for reducing KOA pain in males.

Therapeutic Drug Monitoring of Nirmatrelvir/Ritonavir (Paxlovid) in Patients Treated for COVID-19: Results from a Prospective Multicenter Observational Study

Background: Paxlovid is a combination of the antiviral agents nirmatrelvir and ritonavir indicated for the oral treatment of high-risk, symptomatic patients with coronavirus disease 2019 (COVID-19). As real-world data on the plasma concentrations of nirmatrelvir/ritonavir (Paxlovid) are limited, the aim of this study was to investigate nirmatrelvir/ritonavir plasma trough levels in a clinical setting using therapeutic drug monitoring. Methods: A prospective, noninterventional, multicenter, observational clinical study was conducted in which the plasma trough levels of nirmatrelvir/ritonavir were simultaneously determined by using liquid chromatography tandem mass spectrometry in patients with symptomatic COVID-19. The blood samples were collected on days 1, 3, and 5 after the first full-dose day (day 0), and patient data such as sex, height, weight, renal function, liver enzymes, and concomitant (co-) medications were obtained to describe the plasma levels with respect to potential influencing factors. Results: A total of 46 blood samples from 21 patients were analyzed. The geometric mean Cmin was 4997 ng/mL for nirmatrelvir and 529.4 ng/mL for ritonavir. The plasma concentrations covered a wide range, the highest being observed in patients with advanced age and renally excreted comedications. Patients older than 65 years had a significantly higher risk of achieving excessive plasma trough concentrations above 8840 ng/mL for nirmatrelvir and 1440 ng/mL for ritonavir compared with younger patients (odds ratio 11.2, 95% confidence interval 1.04–120.4). Conclusions: The plasma trough concentrations of nirmatrelvir and ritonavir in patients treated for symptomatic COVID-19 were higher than the reference values of 2210 ng/mL for nirmatrelvir and 360 ng/mL for ritonavir stated in the product characteristics. Advanced age and renally eliminated comedication were identified as possible influencing factors that warrant further investigation.

Development of TiF4-Dendrimer Complex Gel as an Anti-Demineralization Agent for Dentin: An In Vitro Study

ObjectiveThe anti-caries effects of titanium tetrafluoride (TiF4) are well-documented, but its low pH challenges clinical application. This study evaluated PEG citrate dendrimer as a carrier to enhance TiF4 stability and efficacy. MethodsPEG-citrate dendrimer and TiF4-dendrimer gel were synthesized, and their structures confirmed using Fourier Transform Infrared Spectroscopy (FTIR), Hydrogen Nuclear Magnetic Resonance (¹H NMR), and Liquid Chromatography–Mass Spectrometry (LC-MS). Thirty-six intact human teeth were prepared, randomly divided into three groups (n=12) and subjected to pH cycling with the following treatments: titanium tetrafluoride (T), dendrimer (D), and dendrimer with TiF4 (TD). Vickers microhardness and Raman spectroscopy evaluated dentin demineralization. EDS analysis measured titanium and fluoride penetration into dentin in T and TD groups and mineral content (calcium and phosphorus) in all groups compared to controls. ResultsThe T group showed the highest microhardness loss (p<0.001), followed by D and TD groups. EDS analysis revealed no significant difference in titanium and fluorine content between the surface and subsurface in TD (p=0.344), while T had more titanium on the surface (p<0.001). TD had higher subsurface calcium content than T (p=0.008). Raman spectroscopy revealed significant changes in phosphate-to-amide and carbonate-to-amide ratios before and after pH cycling in all groups (p<0.001), with no statistical differences among groups. ConclusionUsing dendrimer as a carrier for TiF4 increased pH and enhanced TiF44 ability to limit dentin demineralization and microhardness loss. Clinical RelevanceThe application of the newly-developed TiF4-dendrimer gel might be an effective approach to prevent/ limit dentin demineralization and dentin caries.

Proteomic profiling identifies classic Hodgkin lymphoma patients at risk of bleomycin pulmonary toxicity

Advances in treating classic Hodgkin lymphoma (cHL) have improved cure rates, with overall survival exceeding 80%, resulting in a growing population of survivors at risk of long-term complications, particularly cardiac and pulmonary toxicity. Bleomycin, a key component of combination chemotherapy, is associated with bleomycin-induced pulmonary toxicity (BPT). Using label-free quantification nano liquid chromatography-tandem mass spectrometry, protein expression in diagnostic lymphoma samples from patients with and without BPT was compared. Results showed differential protein expression and disrupted cellular pathways, suggesting biological differences in BPT risk. Immunohistochemical analysis revealed higher expression of JAK3, BID, and MMP9, and lower expression of CD20, TPD52, and PIK3R4 in patients with BPT. High BID and low CD20 expression were associated with inferior overall survival, while high BID and low JAK3 and CD20 expression were linked to poorer progression-free survival. These findings highlight altered protein profiles in pretreatment cHL biopsies associated with BPT development.

The amino acid metabolism pathway of peripheral T lymphocytes and ketamine-induced schizophrenia-like phenotype.

The intricate interplay between peripheral adaptive immune cells and the central nervous system (CNS) has garnered increasing recognition. Given that alterations in cell quantities often translate into modifications in metabolite profiles and that these metabolic changes can potentially traverse the bloodstream and enter the CNS, thereby modulating the progression of mental illnesses, we sought to explore the metabolic profiles of peripheral immune cells in a ketamine-treated mouse model of schizophrenia. We used flow cytometry to scrutinize the alterations in peripheral adaptive immune cells in a ketamine-induced schizophrenia mouse model. Subsequently, we implemented an untargeted metabolomic approach with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to detect the metabolite profiles of peripheral abnormal lymphocytes and identify differential metabolites present in plasma. We then employed targeted metabolomics using UPLC-MS/MS to quantify the common differential metabolites detected in mouse plasma. Flow cytometry analysis detected a notable increase in the count of peripheral CD3+ T cells in a ketamine-induced schizophrenia mouse model. Subsequent untargeted metabolomics analysis revealed that the amino acid metabolism pathway underwent substantial alterations. A detailed quantification of 22 amino acid profiles in the peripheral plasma indicated significant elevation in the levels of glycine, alanine, asparagine, and aspartic acid. Our ongoing research has yet to conclusively identify the precise amino acid metabolism pathway that serves as the pivotal factor in the manifestation of the schizophrenia-like phenotype induced by ketamine. The peripheral amino acid metabolism pathway is involved in the ketamine-induced schizophrenia-like phenotype. The metabolic profile of peripheral immune cells could provide accurate biomarkers for the diagnosis and treatment of psychiatric diseases.

Pasteurized Akkermansia muciniphila Ameliorates Preeclampsia in Mice by Enhancing Gut Barrier Integrity, Improving Endothelial Function, and Modulating Gut Metabolic Dysregulation

Preeclampsia (PE) is a serious complication of pregnancy linked to endothelial dysfunction and an imbalance in the gut microbiota. While Akkermansia muciniphila (AKK) has shown promise in alleviating PE symptoms, the use of live bacteria raises safety concerns. This study explored the potential of pasteurized A. muciniphila (pAKK) as a safer alternative for treating PE, focusing on its effects on endothelial function and metabolic regulation. A PE mouse model was induced via the nitric oxide synthase inhibitor L-NAME, followed by treatment with either pAKK or live AKK. Fecal metabolomic profiling was performed via liquid chromatography–tandem mass spectrometry (LC-MS/MS), and in vivo and in vitro experiments were used to assess the effects of pAKK on endothelial function and metabolic pathways. pAKK exhibited therapeutic effects comparable to those of live AKK in improving L-NAME-induced PE-like phenotypes in mice, including enhanced gut barrier function and reduced endotoxemia. pAKK also promoted placental angiogenesis by restoring endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production. The in vitro experiments further confirmed that pAKK alleviated L-NAME-induced NO reduction and endothelial dysfunction in human umbilical vein endothelial cells (HUVECs). Metabolomic analysis revealed that both pAKK and live AKK reversed metabolic disturbances in PE by modulating key metabolites and pathways related to unsaturated fatty acid biosynthesis, folate, and linoleic acid metabolism. As a postbiotic, pAKK may support existing treatments for preeclampsia by improving gut barrier function, restoring endothelial function, and regulating metabolic dysregulation, offering a safer alternative to live bacteria. These findings highlight the potential clinical value of pAKK as an adjunctive therapy in managing PE.

Assessment of Serum Metabolism and Eicosanoid Profiling in Pediatric Asthma and Bronchiolitis via Liquid Chromatography-Mass Spectrometry.

Asthma, a prevalent chronic inflammatory respiratory disease among children, was the focus of this study. Serum metabolism profiles were examined in patients diagnosed with both asthma and bronchiolitis by using ultra-high performance liquid chromatography-mass spectrometry. In this study, the serum samples from three distinct groups-comprising patients diagnosed with asthma, bronchiolitis, and a healthy control group-underwent comprehensive non-targeted metabolomics analysis and targeted eicosanoid profiling. Through both univariate and multivariate analyses, significant associations were observed between the pathophysiology of both asthma and bronchiolitis and aberrations in the metabolism of polyunsaturated fatty acids, amino acids, purines, and pathways involving cyclooxygenases and lipoxygenases, indicative of inflammatory processes and immune responses. Furthermore, metabolic changes in phosphatidylethanolamine, saturated and monounsaturated fatty acids, and bile acids were observed in the asthma group. Bronchiolitis was distinguished by disruptions in acyl carnitine and phosphatidylcholine metabolism. This study offers a new perspective on understanding the interplay of pathogenic mechanisms underlying both asthma and bronchiolitis. Its findings are significant for enhancing the diagnostic and therapeutic strategies tailored to asthma stemming from bronchiolitis.

LC-MS/MS method for the simultaneous determination of six phenolic acids in rat plasma and hypoglycemic effects in normal and T2DM rats after oral administration of Eleutherococcus senticosus fruits extract

AbstractEleutherococcus senticosus (Rupr. &amp; Maxim.) Maxim. fruits (ESF) is a natural health food that has been widely used in traditional medicine. This study aimed to establish and validate a rapid and sensitive method for determining of six phenolic acids in plasma of normal and T2DM rats by ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Separation and quantification were performed on a Waters HSS T3 column (100 × 2.1 mm, 1.8 μm) with water (A) and methanol (B). The electrospray ionization (ESI) source was operated in negative ionization mode. Multiple reaction monitoring (MRM) was used to quantitatively analyzed hyperoside m/z 463.2→301.1, caffeic acid m/z 179.1→135.1, chlorogenic acid m/z 353.2→190.9, gallic acid m/z 169.0→125.1, protocatechuic acid m/z 153.1→109.1, and isofraxidin m/z 221.1→191.0, respectively. The hypoglycemic effect of ESF was verified by determining blood glucose and lipid levels in a type 2 diabetes model. This study laid the foundation for exploring ESF clinical guidelines in the future.

Therapeutic potential of Xihuang Pill in colorectal cancer: Metabolomic and microbiome-driven approaches

IntroductionThe Xihuang Pill (XHP), a venerated traditional Chinese medicine, has demonstrated significant anti-cancer capabilities. Despite its proven efficacy, the scarcity of comprehensive pharmacological studies limits the widespread application of XHP. This research endeavor seeks to demystify the therapeutic underpinnings of XHP, particularly in the realm of colorectal cancer (CRC) therapy.MethodsIn this study, mice harboring CT26 tumors were divided into four groups, each administered with either XHP monotherapy, 5-fluorouracil (5-FU), or a combination of both. The tumor growth trajectory was closely monitored to evaluate the effectiveness of these anti-neoplastic interventions. Advanced techniques, including 16S-rDNA gene sequencing and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), were harnessed to scrutinize the gut microbiota and serum metabolite profiles. Immunohistochemical assays were employed to gauge the expression levels of CD4, CD8, and Foxp3, thereby providing insights into the dynamics of tumor-infiltrating lymphocytes within the tumor microenvironment.ResultsOur findings indicate that XHP effectively suppresses the initiation and progression of colorectal tumors. The combinatorial therapy of XHP with 5-FU exhibited an enhanced inhibitory effect on tumor growth. Metabolic profiling revealed that XHP induced notable metabolic shifts, particularly impacting pathways such as steroid hormone synthesis, arachidonic acid metabolism, purine biosynthesis, and renin secretion. Notably, 17α-ethinyl estradiol and α-ergocryptine were identified as serum metabolites with the most substantial increase following XHP administration. Analysis of the gut microbiome suggested that XHP promoted the expansion of specific bacterial taxa, including Lachnospiraceae_NK4A136_group, Clostridiales, Desulfovibrionaceae, and Anaerotignum_sp., while suppressing the proliferation of others such as Ligilactobacilus, Lactobacillus_taiwanensis, and Candidatus_saccharimonas. Immunohistochemical staining indicated an upregulation of CD4 and CD8 post-XHP treatment.ConclusionThis study delineates a potential mechanism by which XHP inhibits CRC tumorigenesis through modulating the gut microbiota, serum metabolites, and reshaping the tumor immune microenvironment in a murine CRC model. These findings contribute to a more profound understanding and potentially broaden the clinical utility of XHP in oncology.

A comprehensive approach to characterizing bioactive compounds from Haplanthodes tentaculatus (L.) R. B. Majumdar using HR-LCMS and MTT assay

The bioactive compounds in Haplanthodes tentaculatus (L.) R. B. Majumdar has demonstrated significant potential in addressing conditions like cancer, diabetes, inflammation, and microbial infections. This study employs high-resolution liquid chromatography mass spectrometry and network analysis to investigate these chemicals. The methanolic extract revealed 92 identified compounds, many of which exhibited inhibitory effects on MDA-MB-231 breast cancer cell growth. Aclacinomycin N, Ganoderic acid Mb, Cucurbitacin E, and Hydroquinidine displayed notable inhibitory effects. The extract demonstrated an IC50 value of 61.41±0.692 μg, showcasing its effectiveness in impeding cancer cell development. While promising, further research is needed to unravel the specific molecular pathways involved. The identification and characterization of distinct chemicals in the extract offer potential leads for medication development. This work underscores H. tentaculatus as a vital source of bioactive substances with potent anticancer properties, emphasizing the need for continued exploration in advancing cancer therapies.

Identification of a Flavanone 2-Hydroxylase Involved in Flavone C-Glycoside Biosynthesis from Camellia sinensis.

Tea contains a variety of flavone C-glycosides, which are important compounds that distinguish tea cultivars and tea categories. However, the biosynthesis pathway of flavone C-glycosides in tea plant remains unknown, and the key enzymes involved have not been characterized. In this study, a liquid chromatography-mass spectrometry method to determine 9 flavone C-glycosides was developed, and the accumulation patterns of 9 flavone C-glycosides in tea plants were examined first. Then, an entry enzyme CsF2H for flavone C-glycoside biosynthesis was identified, which had four cytochrome P450-specific conserved motifs and was targeted to the endoplasmic reticulum. Correlation analysis indicated that the expression level of CsF2H was positively correlated with all contents of 9 flavone C-glycosides. The recombinant CsF2H could convert flavanone (naringenin) into the corresponding 2-hydroxyflavonone (2-hydroxynaringenin), rather than into flavone (apigenin). Heterologous coexpression of CsF2H and CsCGT1 in yeast revealed that the substrate naringenin could be enzymatically converted to flavone mono-C-glycosides vitexin and isovitexin under the catalytic control of CsF2H and CsCGT1 following dehydration. Gene-specific antisense oligonucleotide analysis suggested that suppressing CsF2H significantly reduced the levels of 9 flavone C-glycosides. Together, CsF2H is the first key enzyme that generates flavone C-glycosides through the 2-hydroxyflavanone biosynthesis pathway in tea plants.

LC-HRMS-Based Metabolomics Approach Reveals Antioxidant Compounds from &lt;i&gt;Centella asiatica&lt;/i&gt; Leaves Extracts

Centella asiatica is a medicinal plant widely used as a traditional medicine due to several biological activities, such as antioxidants in Indonesia. This study aims to identify the active antioxidant compounds of C. asiatica leaves extract using a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS)-based metabolomics approach. Extracts were prepared using different concentrations of ethanol p.a., i.e. 70% ethanol, 50% ethanol, 30% ethanol, and water. Antioxidant activity was tested using the 2,2-diphenyl-1-picrylhydrazyl method. The results showed the highest antioxidant activity was C. asiatica extracted by 70% ethanol with IC50 of 72.48 ± 2.42 µg/mL. The positive control was ascorbic acid, having an IC50 value of 3.38 ± 0.04 µg/mL. Ascorbic acid and 70% ethanol extract have strong antioxidant activity. Metabolite profiling using LC-MS/MS could identify 35 metabolites consisting of flavonoids, fatty acids, phenolics, terpenes, and several other groups of compounds. Orthogonal partial least squares-discriminant analysis classified the metabolites into active (ethanol 70% and ethanol 50%) and inactive (ethanol p.a., ethanol 30%, and water) antioxidants. Five metabolites have potential as antioxidants, namely 4,5-dicaffeoylquinic acid (11), kaempferol (13), and three unknown compounds.

Lipid analysis of human primary dermal fibroblasts and epidermal keratinocytes after near-infrared exposure using mass spectrometry imaging

Photobiomodulation (PBM) therapy is the application of near-infrared (NIR) exposure to injuries or lesions to (among others) improve wound healing, reduce inflammation, and decreases acute and chronic pain. However, the understanding of the molecular mechanism of PBM, more specifically the effects of NIR on skin cells is still lacking behind. Lipids are essential components of cellular membranes that are integral to skin structure and function. This study aims to elucidate the impact of NIR exposure on the skin’s lipidome by investigating the molecular effect of NIR exposure on single skin cells. Primary human dermal fibroblasts (NHDFa) and human epidermal keratinocytes (HEKa) were exposed to NIR (850nm) with a dose of 6.5J/cm2 for 5 consecutive days between 09.00 and 12.00 am. A workflow utilizing matrix-assisted laser desorption/ionization mass spectrometry imaging combined with liquid chromatography tandem mass spectrometry for lipidomics analysis was performed. This study provides evidence that adequate exposure of NIR influences lipid metabolism in NHDFa, whereas no alterations were found in HEKa. This work lays the groundwork in explaining the beneficial properties on both skin-related effects and systemic health benefits as seen in clinical studies.

Covalent triazine frameworks as particle electrode for three-dimensional photoelectrocatalytic degradation of oxytetracycline: Synergy effects, pathway, and mechanism.

Photoelectrocatalysis has been widely employed for degrading antibiotics due to its high efficiency. However, the application is significantly impeded by the rapid recombination of photogenerated charge carriers and the limited surface areas of photoelectrodes. In the study, high crystallinity covalent triazine frameworks were fabricated at low temperature of 150°C and firstly used as particle photoelectrode in the three-dimensional photoelectrochemical reactor to degrade oxytetracycline (OTC). SEM, TEM, XRD, XPS, and FT-IR confirmed the successful synthesis of high crystallinity covalent triazine frameworks. Compared to CTF-120 (71.2%) and CTF-180 (46.9%), CTF-150 exhibited excellent OTC removal. Electrochemical impedance, UV-vis absorption spectra, and Mott-Schottky tests showed that CTF-150 demonstrated more wide light absorption range of 501nm and narrow bandgap of 2.52eV, and smaller Rct value under illumination, in comparing to CTF-120 and CTF-180. When the initial concentration of OTC was 50mgL-1, the 86.2% of OTC removal and 62.7% of mineralization were obtained under light irradiation (λ>420nm), current of 10mA, pH of 6.4, electrolyte of 0.1M Na2SO4. The synergy effect between photocatalytic and electrocatalytic processes of CTF-150 not only enhanced by 38.5% current efficiency but also reduced energy consumption to 1.90 kWh m-3. CTF-150 had a wide range of acid-base application and displayed resistance on coexisting ions. Electron spin resonance detection, quenching experiments, and probe experiments illustrated that h+, •O2-, 1O2, and •OH contributed to the degradation of OTC and the generation pathways of •O2-, 1O2, and •OH were verified. Moreover, •O2-, 1O2, and h+ were the main reactive species responsible for OTC removal, while 1O2 was for OTC mineralization. Based on high-performance liquid chromatography-tandem mass spectrometry detection, OTC with benzene ring was decomposed to opening ring products. The acute toxicity, developmental toxicity, bioaccumulation factor and mutagenicity of OTC and its intermediates using T.E.S.T. showed the toxicity of 82.35% degradation products decreased.

Methylated magnetic covalent organic framework for sample preparation and LC-MS/MS detection of 12 tadalafil analogs in dietary supplements

Tadalafil analogs are often illegally added to dietary supplements such as herbal beverages, protein powders and tablet foods. Due to the complexity of the matrices, effective extraction of tadalafil analogs is the key to achieve accurate quantification. Therefore, it is of great significance to establish a rapid and effective method for the analytical determination of tadalafil analogs in complex matrices. In this study, a novel methylated magnetic covalent organic framework, Fe3O4@TFPB-OT, was successfully synthesized under mild conditions. Fe3O4@TFPB-OT demonstrated robust adsorption capabilities, with capacities ranging from 52.4 to 90.9 mg/g for the tadalafil analogs. Several pre-enrichment parameters were optimized, including adsorbent dosage, extraction time, pH, shaking time, elution solvent, and desorption time. The applicability of Fe3O4@TFPB-OT was evaluated as effective adsorbents for the magnetic solid-phase extraction (MSPE) of 12 tadalafil analogs in dietary supplements. Combined with high-performance liquid chromatography-tandem mass spectrometry, the limits of detection (LODs) of this method ranged from 0.005 to 0.05 μg/L in liquid matrices and from 0.005 to 0.05 μg/kg in solid matrices, showing good sensitivity and recoveries ranged from 56.1 % to 90.9 %with relative standard deviations lower than 3.9 %, demonstrating good accuracy and precision. Additionally, the adsorbent retained its effectiveness after at least ten reuse cycles, indicating significant reusability. This study provides an effective method for the analysis and detection of tadalafil analogs in dietary supplements and has great potential for application.