Xenobiotica最新文献

The mutagenicity and bioactivation potential of N-nitrosoparoxetine, a N-nitrosamine drug substance related impurity (NDSRI) of the marketed antidepressant paroxetine, was characterised in vitro.N-Nitrosoparoxetine was not mutagenic in an OECD 471-compliant bacterial reverse mutation assay even under experimental conditions that supported oxidative metabolism by CYP enzymes. The major biotransformation pathways of N-nitrosoparoxetine paralleled the ones previously noted with paroxetine. Virtually all stable metabolites of N-nitrosoparoxetine in human, rat, and hamster liver tissue were derived from phase 2 conjugations on an unstable catechol intermediate, generated from the oxidative 1,3-benzodioxole ring scission by CYP enzymes. The piperidine ring in N-nitrosoparoxetine was resistant to the α-carbon oxidation step leading to piperidine ring scission, and to the eventual formation of a DNA-reactive electrophilic species.CYP reaction phenotyping studies demonstrated that paroxetine was exclusively metabolised by human CYP2D6, whereas N-nitrosoparoxetine was subject to metabolism by multiple human CYP isoforms including CYP2C19, CYP2D6, and CYP3A4.Whether most NDSRIs derived from parent amine precursors that are resistant to α-carbon oxidation by CYPs will also be devoid of a mutagenic response in vitro needs to be scrutinised further with additional examples to bolster structure-genotoxicity relationships of complex NDSRIs.

Aflatoxin B₁ (AFB₁) is a potent hepatocarcinogen. It is activated by cytochrome P450 3A4 (CYP3A4) into a DNA-reactive epoxide linked to liver cancer.Six scopoletin metabolites were predicted using SmartCYP. Their lipophilicity was assessed via BioTransformer 3.0; molecular docking was performed with CBDock 2 using CYP3A4 (PDB ID: 1TQN).Phase I Metabolite 2 showed the highest binding affinity (Vina score: -7.4 kcal/mol) and was selected for a 100 ns molecular dynamics (MD) simulation using Desmond with the OPLS3e force field.The metabolite maintained stable binding (RMSD < 1.0 Å), showed >80% hydrophobic interaction occupancy with Phe215, Phe108, and Leu210, and formed transient hydrogen bonds with Ser119; MM-GBSA predicted a binding free energy of -75 kcal/mol.Scopoletin metabolites may competitively inhibit AFB₁ activation by binding CYP3A4, indicating potential for chemoprevention pending experimental confirmation.

Xevinapant, a drug previously under development for head and neck cancer, was investigated to determine its intrinsic clearance (CL_int) in vitro and assess the involvement of CYP enzymes in its metabolism. Extensive in vitro studies showed very low turnover, necessitating advanced methodologies to accurately measure CL_int values.Two novel in vitro assays, using a modified suspension hepatocyte protocol or 3D hepatocyte spheroid cultures, allowed measuring hepatic turnover of xevinapant with very low CL_int values of 1.3 or 0.3 µL/min/10⁶ cells, respectively. Reaction phenotyping using specific inhibitors, enabled by enhanced detection capabilities in spheroids, identified primarily CYP3A (> 50%) as contributor to the hepatic metabolism of xevinapant.In vitro-in vivo extrapolation, in combination with data from the human mass balance study, revealed that hepatic metabolism, primarily mediated by CYP3A, accounts for approximately 30% of the overall clearance. The remaining clearance is renal (∼20%) and metabolic, but potentially extrahepatic (∼50%).This research highlights the importance and benefits of utilising advanced in vitro techniques, such as human hepatocyte spheroids, to accurately characterise drug metabolism, providing valuable insights for pharmacokinetic evaluations and, ultimately, supporting the development of a PBPK model and understanding the DDI risk of xevinapant.

This study aimed to develop a targeted metabolomics workflow using low-resolution tandem mass spectrometry (MS/MS) to identify metabolic alterations in zebrafish (Danio rerio) embryos exposed to environmentally relevant concentrations of the antibiotic's amoxicillin and clarithromycin.Zebrafish embryos were exposed to the lowest concentrations (1 µg/L) and the highest concentration (1 mg/L) of amoxicillin and clarithromycin. A library-assisted multiple reaction monitoring-enhanced product ion (MRM-EPI) approach was applied using a QTRAP LC-MS/MS system, enabling the detection and structural confirmation of 108 endogenous metabolites. A targeted MRM-EPI method was subsequently optimised for sensitivity, reproducibility, and specificity. Multivariate statistical analyses, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), were performed to assess metabolic differences between exposed and control groups.Exposure to both antibiotics resulted in significant alterations in amino acid, purine, lipid, and energy metabolism, indicating that even sub-lethal concentrations can disrupt vital physiological processes in zebrafish embryos. These findings highlight the sensitivity of metabolomics for detecting early biochemical perturbations and support the use of zebrafish embryos as a practical and ethically suitable model for environmental toxicity assessment. The developed MRM-driven workflow provides a reproducible platform for predictive toxicology and ecological risk evaluation.

This study aimed to apply a machine learning workflow to identify the most relevant biological parameters for predicting both the dose and the route of crack cocaine administration.Seventeen variables were evaluated in rats exposed to different doses of crack cocaine, either intraperitoneally (18 or 36 mg/kg, i.p.) or via passive inhalation (25, 50, or 100 mg). Random forest (RF) analysis was used to build predictive models, feature importance analysis to identify key variables, and interaction dependence analysis to explore relationships among variables.Eighty percent of the data was used for training and 20% for testing. The model achieved 85% accuracy in the training phase and 100% in the test phase. During training, the highest accuracy was observed for the 100 mg inhaled group, while the lowest was for the 50 mg inhaled group. Notably, 20% of the 50 mg i.p. cases were misclassified as 36 mg i.p. Feature importance analysis highlighted four key predictors: liver karyolysis, kidney Ki-67 expression, liver binucleation, and escape behaviour.These findings demonstrate that machine learning (ML) can accurately predict both dose and route of crack cocaine exposure, and can highlight biologically relevant parameters involved in the drug's systemic and behavioural effects.

Objective: This study evaluated the effects of Serfurosterone A (SSA) from Achyranthes bidentata Bl. on dexamethasone (DEX)-induced osteoblast dysfunction and its intestinal permeability.

Methods: The anti-osteoporotic effects of SSA were assessed by MTT assay, flow cytometry, osteogenic differentiation induction, and western blotting. Intestinal permeability and transport mechanisms were investigated using Caco-2 cell models and single-pass intestinal perfusion (SPIP) in rats.

Results: SSA (5-50 µM) increased the viability and proliferation of DEX-injured MC3T3-E1 cells, enhanced alkaline phosphatase (ALP) activity, and promoted mineralized nodule formation. Western blot analysis suggested that SSA's effects may involve activation of the Wnt/β-catenin signaling pathway, characterized by upregulation of β-catenin and downregulation of GSK3β. In the Caco-2 assays, SSA showed moderate absorption (Papp 1.551-2.443 × 10^-6cm/s; ER 0.751-0.898) via passive transcellular transport. SPIP experiments further indicated efficient absorption across all intestinal segments (Peff > 2 × 10^-5cm/s), with the duodenum as the main absorption site.

Conclusions: SSA mitigates DEX-induced osteogenic inhibition and exhibits favorable intestinal absorption, suggesting its potential as a promising oral candidate for glucocorticoid-induced osteoporosis (GIOP). These results underscore the therapeutic promise of Achyranthes-derived phytosterols for future drug development.

Considering the important role of mitochondria in mammalian cells and the close correlation between mitochondrial dysfunction and various diseases, this study evaluated the potential toxicity of glyphosate on mitochondrial function in swine heart mitochondria.The results indicated that glyphosate did not have a significant effect on mitochondrial respiration, mitochondrial swelling, and F₁F_O-ATPase activity under the experimental conditions tested.These findings suggest that, in this model, glyphosate alone may not exert a direct cardiotoxic effect on mitochondrial bioenergetics.Caution is warranted when extrapolating these results to human health, as differences in species, exposure levels, and experimental conditions may influence outcomes.The toxicity observed in glyphosate-based herbicides could involve adjuvants or synergistic interactions between glyphosate and other formulation components, as proposed by other studies.

Black American Ginseng (Panax quinquefolium L.) is a traditional Chinese medicine taken orally. While saponins from American Ginseng are known to enhance memory, the effects and mechanisms of Black American Ginseng saponins remain unclear.This study investigates their potential in alleviating memory impairment in ageing mice. UPLC-Q-Orbitrap-MS/MS was used to identify compounds in Black American Ginseng, and network pharmacology predicted potential targets. The Morris water maze test assessed cognitive function, while Western blot and ELISA measured BDNF, TrkB, inflammatory markers (IL-1β, TNF-α, IL-6), and the activation of the PI3K/AKT/CREB signalling pathway. Networking pharmacology and PPI analysis identified PIK3CA, EGFR, and PIK3R1 as key targets, with KEGG enrichment highlighting the PI3K/AKT pathway. Behavioural tests confirmed that Black American Ginseng saponins significantly improved memory in ageing mice. Molecular analyses revealed upregulation of BDNF and TrkB and suppression of IL-1β and IL-6. Additionally, Western blot confirmed activation of the PI3K/AKT/CREB pathway, supporting its neuroprotective role.Black American Ginseng saponins enhance cognitive function by modulating neurotrophic signalling and reducing neuroinflammation.These findings provide new insights into their potential therapeutic application for age-related cognitive decline.

1. To study the effects of calycosin on palmitic acid-induced HepG2 cells, as well as the potential mechanisms of action.

2. Potential targets of calycosin for the alleviation of insulin resistance were predicted by network pharmacology. Glucose concentration in the culture medium was determined by the GOD-POD method. The model of insulin resistance was established by palmitic acid-induced HepG2 cells. Effects of palmitic acid and calycosin on HepG2 cell activity were determined using an MTT assay kit. The expression levels of AKT1 and FOXO3a were detected by western blot. The expression level of hsa-miR-324-3p was detected by RT-qPCR. Dual luciferase reporter assay to detect targeting of AKT1 by hsa-miR-324-3p.

3. AKT1 was predicted and validated as a potential target of calycosin for treatment of insulin resistance. The model of insulin resistance was successfully established by palmitic acid-induced HepG2 cells. Up-regulation of AKT1 expression inhibits FOXO3a entry into the nucleus. Calycosian was demonstrated to concentration-dependently increase the sensitivity of insulin resistance cells to insulin. The hsa-miR-324-3p was proven to exist in insulin-resistant cells. Hsa-miR-324-3p was found to target AKT1 involved in the alleviation of insulin resistance.

4. Calycosin inhibits FOXO3a nuclear translocation by regulating the hsa-miR-324-3p/AKT pathway, thus alleviating insulin resistance.

Astragalin (AST), a flavonoid, shows promise for neurodegenerative diseases like Parkinson's disease (PD), cognitive impairment (CI), and depression. However, its efficacy in treating neurodegenerative diseases and the underlying molecular mechanisms remain unclear.This study aims to evaluate the metabolite profile, pharmacokinetics, toxicity, molecular targets, and potential biological activities of AST. Thirty-one AST metabolites formed through Phase II reactions (O-glucuronidation, O-sulfation, and methylation) were found.AST and its metabolites partially violate Lipinski's Rule of Five, including molecular weight and hydrogen bond donors, impacting drug-likeness. However, AST and its metabolites have favourable safety and potential anti-neurodegenerative and antidepressant effects.AST shows strong binding affinities with key neuroinflammatory targets, including IL1B, IL6, TNF, NOS2, PTGS2, SERT, caspase-3, caspase-8, and GABAa receptor, and network analysis highlights its association with neuroinflammatory pathways.Collectively, these findings support AST as a potential neurotherapeutic candidate and offer a basis for further in vitro and in vivo validation.