Activity cliffs (AC) correspond to large potency differences between highly similar compounds and pose a persistent challenge for both predictive modeling and de novo molecular design, particularly in small and underexplored areas of the chemical space. In this study, we introduce an AC-aware generative framework for the de novo design of anticancer thiazolidinone derivatives relevant to non-small cell lung cancer. We identify difficult regions of structure–activity landscape and extract chemical pattern signals hidden in its discontinuities directly from AC pairs using a dedicated algorithm. These signals are incorporated into a fragment-based generative pipeline to guide molecular construction and candidate selection. Compared with a standard QSAR-guided approach, the proposed framework yields a higher fraction of candidates with favorable docking profiles across multiple cancer-relevant targets and produces ligands with more stable binding modes in molecular dynamics simulations. Among the top five candidates selected by a molecular dynamics, multi-metric consensus combining docking affinity, binding stability (ligand and pocket RMSD/RMSF), and energetic criteria, four were generated using the AC-aware CAFE LATE strategy. The two highest-ranked hits exhibited binding energies of − 7.78 and − 7.70 kcal/mol, markedly more favorable than the native reference (− 4.09 kcal/mol), and consistently outperformed native ligands across all evaluated stability metrics. Those results suggest that explicit use of AC information can improve the quality of de novo generated small-molecule candidates in data-limited settings. This study introduces a new AC-informed small-molecule design framework that explicitly exposes crucial structure–activity information hidden in steep regions of the SAR landscape and uses it as an operationalized design signal. Our algorithm converts AC knowledge into reverse QSAR and generation leverage, enabling exploration of unknown areas of the chemical space, and discovery of the best performing candidates supported in molecular dynamics simulations. To the best of our knowledge, this is the first reverse QSAR and fragment-based generative framework to operationalize AC information at the fragment level within a unified machine learning workflow.

Human serum albumin (HSA) binding critically influences drug distribution and pharmacokinetics. In this study, HSA affinity chromatography was integrated with machine-learning-based quantitative structure-retention relationship (QSRR) modeling to elucidate structural determinants of albumin binding in a library of 115 fluoroquinolone (FQs) derivatives. Experimentally determined logkHSA values were obtained using biomimetic chromatography, and these were then used as modelling endpoints. Following descriptor reduction via Least Absolute Shrinkage and Selection Operator (LASSO) and systematic benchmarking of 42 regression algorithms, support vector regression (SVR) and nu-support vector regression (ν-SVR) with radial basis function kernels demonstrated superior predictive performance. A parsimonious 12-descriptor ν-SVR model achieved strong calibration and validation metrics (R2 = 0.916, Q2test = 0.823, concordance correlation coefficient (CCC) = 0.899) and satisfied Organisation for Economic Co-operation and Development (OECD) criteria, including applicability domain assessment. Shapley Additive exPlanations (SHAP)-based interpretation revealed that albumin binding is governed by a balance between hydrophobic surface area and distributed electronic properties, whereas excessive localized polarity and quaternary ammonium functionalities reduce affinity. This experimentally anchored and interpretable modeling framework provides mechanistic insight into HSA binding in fluoroquinolones and offers a robust tool for rational pharmacokinetic optimization. Furthermore, in order to make the model easily accessible to users, we have packaged it in the form of an online application.

Rifampicin-resistant Mycobacterium tuberculosis (RR-TB) and methicillin-resistant Staphylococcus aureus (MRSA) underscore the need for new antibacterial chemotypes active across M. tuberculosis M. tuberculosis and Gram-positive pathogens. Both thiourea and tetrazole are well-established scaffolds in the scientific community for their promising antibacterial properties. The combination of tetrazole and thiourea moieties into a single molecular framework presents a promising strategy to overcome antimicrobial resistance. We designed and synthesized a series of tetrazole–thiourea derivatives (1–9) and a bis-tetrazole hybrid (10) through a one-step synthetic approach. Their antimicrobial potential was evaluated using a combination of in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions, experimental lipophilicity determination (logD), and in vitro antibacterial assays against both reference and multidrug-resistant staphylococcal strains. Additionally, antitubercular activity was assessed against drug-sensitive, multidrug-resistant (MDR), and extensively drug-resistant (XDR) M. tuberculosis isolates. Molecular docking studies were performed to explore the binding interactions of the compounds with dihydrofolate reductase (DHFR) and penicillin-binding protein 4 (PBP4). Compound 2, bearing a trifluoromethyl substituent, was the most potent. It achieved sub-µg/mL minimum inhibitory concentrations (MICs, 0.1–0.5 µg/mL) against staphylococci, comparable to ciprofloxacin, and maintained strong antitubercular activity (MIC = 0.5 µg/mL) across drug-sensitive, MDR, and XDR strains. Docking supported a dual-target mechanism involving DHFR and PBP4, providing a plausible rationale for its broad antibacterial efficacy. Despite higher lipophilicity within the series, compound 2 showed favorable ADMET predictions and experimental logD values in the developable range. The tetrazole–thiourea scaffold, exemplified by compound 2, delivers dual efficacy against multidrug-resistant staphylococci and M. tuberculosis. These findings position compound 2 as a promising lead and a rational starting point for hit-to-lead optimization focused on potency–permeability balance and experimental confirmation of dual-target engagement.

Activity cliffs (ACs), defined as near structural neighbors with large potency differences, provide high-value information on structure-activity relationship discontinuities that medicinal chemists have leveraged for years. Yet modern artificial intelligence-based discovery frameworks often smooth this signal, yielding confident but unrealistic proposals. We present a three-layer roadmap that treats ACs as a first-class design feature: representation is tuned to expose AC signal during pretraining and sampling; evaluation focuses on steep regions with early recognition, pair-level retrieval, and calibrated uncertainty under fair, series-aware splits; and de novo generation is steered toward the best candidates. Integrated as a closed, self-improving loop, this framework helps practitioners build AC-aware drug design tools.

INTRODUCTION:Heterocyclic compounds remain cornerstones of contemporary drug discovery because their ring-embedded heteroatoms confer adaptable electronics, conformational flexibility, and a broad spectrum of biological activities. The skeleton structure of 4-thiazolidinone is present in many cytotoxically active compounds and is often used in the design of new antitumor agents. This study aimed to synthesize, characterize, and evaluate the anticancer potential of fifteen new (2-imino-4-oxo-1,3-thiazolidin- 5-yl)acetic acid derivatives. METHOD:Compounds were synthesized using a consistent synthetic route involving a reaction between a thiourea derivative and maleic anhydride, which formed the thiazolidin- 4-one ring through cyclization. The compounds were then categorized into three sets based on the attached heterocyclic rings (tryptamine, thiazole, and 1,2,4-triazole). The NMR and X-ray analysis followed the synthesis. Apoptotic effects, cell cycle arrest, IL-6 suppression, docking, and dynamics simulations were conducted. Preliminary cytotoxic activity was tested on metastatic colorectal cancer (SW620) and human breast adenocarcinoma (MDA-MB-231) cell lines using the MTT assay. RESULT:Compounds 5, 6, and 7 demonstrated notable selectivity indexes (4.73, 2.42, 4.16, respectively) and were further investigated for their mechanisms of action, revealing pro-apoptotic properties and the ability to induce cell cycle arrest. Additionally, compound 5 inhibited IL-6 secretion by 76%. in silico studies revealed the formation of an energetically stable complex between compound 5 and the EGFR crystal structure (min/- max binding affinities of -9.4|-8.0 kcal/mol, compared to the -7.71 kcal/mol for the native ligand). DISCUSSION:This preliminary study provides compelling data on synthesized derivatives, but more advanced testing is needed to assess their therapeutic value fully. Compared with earlier reports on related thiazolidinone scaffolds, the present derivatives exhibit improved potency, clearer selectivity, and mechanistic features consistent with EGFR inhibition and cytokine modulation. CONCLUSION:These findings validate (2-imino-4-oxo-1,3-thiazolidin-5-yl)acetic acid as a privileged core for cytotoxic lead generation and indicate that strategic substitution with either a tryptamine moiety (compound 5) or a 1,2,4-triazole ring (compound 7) is particularly advantageous. These compounds are promising EGFR-targeting anticancer candidates, warranting further investigation.

This study examines the synthesis and biological evaluation of novel tetrazole derivatives of 3,3'-dimethoxybenzidine as potential anticancer agents, focusing on their cytotoxic, apoptotic, and anti-inflammatory properties. Ten derivatives were synthesized using thioureas as precursors, characterized through spectroscopic methods, and assessed for their in silico toxicological profiles using the ADMET-AI and ProTox 3.0 platforms. In vitro cytotoxic activity was evaluated against four human cancer cell lines (HTB-140, A549, HeLa, SW620) and one normal cell line (HaCaT) using MTT and LDH assays. Mechanistic studies included apoptosis assessment via flow cytometry and interleukin-6 (IL-6) analysis using ELISA. The synthesized tetrazole derivatives demonstrated significant anticancer potential, exhibiting selective cytotoxicity against cancer cell lines, robust induction of apoptosis, and a notable reduction in IL-6 levels. Their favorable toxicity profiles, as observed in both in silico and in vitro evaluations, support their potential as promising candidates for further development. The tested compounds showed strong inhibitory activity against the apoptosis regulator Bcl-2, with binding affinities comparable to those of native ligands. Western blot analysis revealed a dramatic loss of Bcl-2 protein expression in selected cancer cells during exposure to compound 5. Additionally, this research highlights the innovative use of hazardous substrates in drug discovery, aligning with the principles of green chemistry. Future efforts should focus on optimizing the most active derivatives and conducting in vivo studies to confirm their therapeutic potential and safety.

Furanocoumarins, known for their diverse bioactivity, were chemically modified to develop new derivatives with potential anticancer properties. This study reports the synthesis and comprehensive biological evaluation of seven aminoalkyl furanocoumarin derivatives. In vitro cytotoxicity was assessed against four human cancer cell lines (HTB-140, A549, HeLa, SW620) and a normal keratinocyte line (HaCaT) using MTT and LDH assays. Compounds 4 and 6 demonstrated the strongest antiproliferative effects, particularly against SW620 and HTB-140 cells, with IC₅₀ values around 11-18 µM, indicating potent anticancer activity. Flow cytometry revealed that these effects were largely mediated through apoptosis, not nonspecific toxicity. Molecular docking studies identified interactions with EGFR and Bcl-2 family proteins, suggesting a pro-apoptotic mechanism, though additional pathways may contribute to their selectivity. Importantly, antimicrobial screening showed negligible activity against representative Gram-positive and Gram-negative strains, indicating a low risk of microbiota disruption - an important feature for cancer therapy. These findings position furanocoumarin derivatives, particularly compounds 4 and 6, as promising lead structures for the development of selective, microbiota-sparing anticancer agents.

A considerable percentage of ineffective treatment in pulmonary arterial hypertension (PAH) may be related to subtherapeutic dosage or non-adherence. The aim of the study was to develop a simple analytical method suitable for plasma determination of selected drugs: riociguat (RIO), bosentan (BOS) and macitentan (MAC) administered to PAH patients. An isocratic HPLC-UV system (Spectra Physics - Shimadzu) with a manual injector (50 μL loop) was applied. Chromatographic analysis was performed using a Suplecosil LC-CN column (150 × 4.6 mm, 5 μm) protected with a Supelguard precolumn at room temperature. The separation was carried out using the mobile phase: CH3CN:H2O:0.5 M KH2PO4:85 % H3PO4 (172:324.2:3.7:0.1, v/v) at a flow rate of 1.8 mL/min. Ethyl acetate (4 mL) was used for 10-min liquid-liquid extraction from 0.4 mL alkalized plasma sample. Detection was performed at λ = 245 nm chosen as a compromise between signal intensity and matrix interference. The analytes were eluted at retention times of 4.4 min (RIO), 5.4 min (BOS), 8.9 min (MAC) and 7.8 min for gallopamil (internal standard, GAL). The method was found linear and calibrated in the ranges: 5-1000 ng/mL for RIO, 10-2000 ng/mL for BOS and 20-2000 ng/mL for MAC, with r2 of 0.9991 for RIO, 0.9983 for BOS, and 0.9949 for MAC, respectively. Within the given ranges, the method ensured reliable results with the required precision and accuracy: ≤15 % (≤20 % for LLOQ). There was no significant carryover effect. The method has been successfully used in pilot study on adherence in patients treated for PAH, enabling monitoring of RIO, BOS and MAC. Drug concentrations were assessed in samples taken before (C0) and 3 h after drug administration (C3). For RIO, BOS and MAC, the developed method was suitable for both C0 and C3 samples, allowing steady-state drug determination if used. The presented method can be recommended to laboratories equipped with basic HPLC apparatus as an attractive analytical tool for both TDM and adherence studies.

Thiazolidinone is a scaffold known for its diverse biological activities, drawing the interest of researchers seeking to explore its potential. Numerous libraries of molecules with diverse structures and properties can be created based on this scaffold. We propose the extraction of compounds with a defined central skeleton, resulting from a repeatable methodology of synthesis, to analyze the biological properties of a heterogeneous set of molecules. This review offers a comprehensive overview of recent research, focusing on a homogeneous group of (2-imino-4-oxo-1,3-thiazolidin-5-yl)acetic acid derivatives. It highlights the most promising compounds that have emerged from recent studies, their molecular targets, and the underlying mechanisms contributing to their biological activity.

In the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity. Here, we proposed how to modify protocols presented by Valko into column safety conditions and evaluated their robustness using fractional factorial design. For robustness testing, four factors were selected: column temperature, mobile phase flow rate, maximum isopropanol concentration in the mobile phase, and buffer pH. Elaborate methods have been applied for the analysis of HSA affinity for three groups of antibiotic-oriented substances that vary in chemical structure: fluoroquinolones, sulfonamides, and tetrazole derivatives. Furthermore, based on the reversed-phase chromatography the workflow of pilot studies was proposed to select molecules that have high affinity to HSA and can not be eluted from the HSA column using the concentration of organic modifier recommended by the column manufacturer.

Chimeric antigen receptor T-cell (CAR-T) therapy is a novel anticancer therapy using autologous or allogeneic T-cells. To date, six CAR-T therapies for specific B-cell acute lymphoblastic leukemia (B-ALL), non-Hodgkin lymphomas (NHL), and multiple myeloma (MM) have been approved by the Food and Drug Administration (FDA). Significant barriers to the effectiveness of CAR-T therapy include cytokine release syndrome (CRS), neurotoxicity in the case of Allogeneic Stem Cell Transplantation (Allo-SCT) graft-versus-host-disease (GVHD), antigen escape, modest antitumor activity, restricted trafficking, limited persistence, the immunosuppressive microenvironment, and senescence and exhaustion of CAR-Ts. Furthermore, cancer drug resistance remains a major problem in clinical practice. CAR-T therapy, in combination with checkpoint blockades and bispecific T-cell engagers (BiTEs) or other drugs, appears to be an appealing anticancer strategy. Many of these agents have shown impressive results, combining efficacy with tolerability. Biomarkers like extracellular vesicles (EVs), cell-free DNA (cfDNA), circulating tumor (ctDNA) and miRNAs may play an important role in toxicity, relapse assessment, and efficacy prediction, and can be implicated in clinical applications of CAR-T therapy and in establishing safe and efficacious personalized medicine. However, further research is required to fully comprehend the particular side effects of immunomodulation, to ascertain the best order and combination of this medication with conventional chemotherapy and targeted therapies, and to find reliable predictive biomarkers.

In this work, we investigated the antitubercular properties of Ciprofloxacin derivatives conjugated with menthol and thymol moieties. For the sixteen derivatives, we established minimal inhibitory concentrations (MIC) using isolates of Mycobacterium tuberculosis that were resistant or susceptible to other antibiotics. For the most potent compound 1‐cyclopropyl‐6‐fluoro‐7‐{4‐[6‐((1R,2S,5R)‐2‐isopropyl‐5‐methylcyclohexyloxy)‐6‐oxohexyl]piperazin‐1‐yl}‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylic acid ( 6 ), we determined fractional inhibitory concentration index (FICI) values to confirm antibacterial susceptibility and synergistic effects with other reference drugs. In addition, chromatographic studies of all the derivatives demonstrated a significant three to four-fold increase in lipophilicity and affinity to phospholipids compared to Ciprofloxacin. Finally, we conducted structure-based studies of the investigated compounds using molecular docking and taking into account protein target mutations associated with fluoroquinolone resistance. In summary, our findings indicate that the investigated compounds possess tuberculostatic properties, with some showing similar or even better activity against resistant strains compared to reference drugs. Increased lipophilicity and affinity to phospholipids of the new derivatives can offer several advantages for new drug candidates, beyond just improved cell membrane penetration. However, further studies are needed to fully understand their safety, efficacy, and mechanism of action.

Sixteen new Ciprofloxacin derivatives were designed and successfully synthesized. In an in silico experiment, lipophilicity was established for obtained compounds. All compounds were screened for antimicrobial activity using standard and clinical strains. As for Gram-positive hospital microorganisms, all tested derivatives were active. Measured MICs were in the range 1–16 µg/mL, confirming high antimicrobial potency. Derivative 12 demonstrated activity against all standard Gram-positive Staphylococci, within the range of 0.8–1.6 µg/mL and was confirmed as the leading structure with MICs 1 µg/mL for S. pasteuri KR 4358 and S. aureus T 5591 (clinical strains). All compounds were screened for their in vitro cytotoxic properties via the MTT method. Three of the examined compounds (3, 11 and 16) showed good activity against cancer cells, and in parallel were found not to be cytotoxic toward normal cells. Doxorubicin SI ranged 0.14–1.11 while the mentioned three ranged 1.9–3.4. Selected Ciprofloxacin derivatives were docked into the crystal structure of topoisomerase II (DNA gyrase) in complex with DNA (PDB ID: 5BTC). In summary, leading structures were established (3, 11, 12 and 16). We have observed poor results in preformed studies for disubstituted derivatives, suggesting that 3-oxo-4-carboxylic acid core is the active DNA-gyrase binding site, and when structural changes were made in this fragment, there was an observed decrease in antibacterial potency.

Biological activity and molecular structure of two series of electrochemically obtained Cu(II) complexes with tautomeric 1,5-disubstituted tetrazole derivatives (1-(2-fluorophenyl)-5-(4-methoxyanilino)-5H-tetrazol-1-ium and 5-(2-fluoroanilino)-1-(4-methoxyphenyl)-5H-tetrazol-1-ium) were studied. In contrast to microbiological activity, promising and selective antitumor activity against human metatstatic prostate cancer cell line (PC-3) was found. In order to simulate the cellular living environment, the molecular structure of the tested compounds was determined for the samples in the form of a solution. Powder compounds were tested for comparison. Direct structural data of coordination polyhedra were obtained using the XANES and EXAFS techniques, which, using a dedicated methodology based on the applied XAFS spectroscopy, were used to determine the molecular models of the tested compounds.

Eleven novel imide-tetrazoles were synthesized. In the initial stage of research, in silico structure-based pharmacological prediction was conducted. All compounds were screened for antimicrobial activity using standard and clinical strains. Within the studied group, compounds 1–3 were recognized as leading structures with the most promising results in antimicrobial studies. Minimal inhibitory concentration values for compounds 1, 2, 3 were within the range of 0.8–3.2 μg/mL for standard and clinical Gram-positive and Gram-negative bacterial strains, showing in some cases higher activity than the reference Ciprofloxacin. Additionally, all three inhibited the growth of all clinical Staphylococci panels: Staphylococcus aureus (T5592; T5591) and Staphylococcus epidermidis (5253; 4243) with MIC values of 0.8 μg/mL. Selected compounds were examined in topoisomerase IV decatenation assay and DNA gyrase supercoiling assay, followed by suitable molecular docking studies to explore the possible binding modes. In summary, the presented transition from substrate imide-thioureas to imide-tetrazole derivatives resulted in significant increase of antimicrobial properties. The compounds 1–3 proposed here provide a promising basis for further exploration towards novel antimicrobial drug candidates.

Twelve novel derivatives of N-(furan-2-ylmethyl)-1H-tetrazol-5-amine were synthesized. For obtained compound 8, its corresponding substrate single crystals were isolated and X-ray diffraction experiments were completed. In the initial stage of research, in silico structure-based pharmacological prediction was conducted. All compounds were screened for their antibacterial and antimycobacterial activities using standard and clinical strains. The cytotoxic activity was evaluated against a panel of human cancer cell lines, in contrast to normal (HaCaT) cell lines, by using the MTT method. All examined derivatives were found to be noncytotoxic against normal cell lines. Within the studied group, compound 6 showed the most promising results in antimicrobial studies. It inhibited four hospital S. epidermidis rods’ growth, when applied at the amount of 4 µg/mL. However, the most susceptible to the presence of compound 6 was S. epidermidis T 5501 851/19 clinical strain, for which the MIC value was only 2 µg/mL. Finally, a pharmacophore model was established based on lead compounds from this and our previous work.

Seven novel derivatives of bis(2-aminoethyl)amine were synthesized. For compounds 1 and 7 single crystals were isolated and X-ray diffraction experiments were done. Lipophilicity and drug likeness were calculated in the initial stage of research. All compounds were screened for their in vitro cytotoxic activity against a panel of human cancer cell lines, which is contrary to normal (HaCaT) cell lines, by using the MTT method. Studies were followed by lactate dehydrogenase assay, apoptotic activity, and interleukin-6 assay. Within the studied group, compound 6 showed the most promising results in all biological studies. The strongest influence in A549 cells was denoted for derivative 4, which inhibited interleukin release almost tenfold, as compared to the control.

A series of halogenated (4-methoxyphenyl)-1H-tetrazol-5-amine regioisomers (1a-9a, 1b-9b) were synthesized from their corresponding thiourea analogues (1-9). The synthesis pathway was confirmed by an X-ray crystallographic studies of 1a, 1b and 5a. Title derivatives were tested for their in vitro antitubercular activity against standard, "wild-type" and atypical mycobacteria. The highest therapeutic potential was attributed to isomeric N-(bromophenyl)tetrazoles 8a and 9a. Their growth-inhibitory effect against multidrug-resistant Mycobacterium tuberculosis Spec. 210 was 8-16-fold stronger than that of the first-line tuberculostatics. Other new tetrazole-derived compounds were also more or equally effective towards that pathogen comparing to the established pharmaceuticals. Among non-tuberculous strains, Mycobacterium scrofulaceum was the most susceptible to the presence of the majority of tetrazole derivatives. The synergistic interaction was found between 9a and streptomycin, as well as the additivity of both 8a and 9a in pairs with isoniazid, rifampicin and ethambutol. None of the studied compounds displayed antibacterial or cytotoxic properties against normal and cancer cell lines, which indicated their highly selective antimycobacterial effects. (C) 2019 Elsevier Masson SAS. All rights reserved.

Four 2-(1H-indol-3-yl)ethylthiourea derivatives were prepared by condensation of 2-(1H-indol-3-yl)ethanamine with the corresponding aryl/alkylisothiocyanates in a medium-polarity solvent. Their structures were confirmed by spectral techniques, and the molecular structure of 3 was determined by X-ray crystal analysis. For all derivatives, the binding affinities at the 5-HT2A and 5-HT2C receptors, as well as their functional activities at the 5-HT1A and D-2 receptors, were determined. The arylthioureas 1 and 4 were the most active at the 5-HT1A receptor, showing, at the same time, significant selectivity over the studied 5-HT2 and D-2 receptor subtypes. The compounds were tested for their pharmacological activities within the central nervous system in relevant mouse models. The involvement of the serotonergic system in the activity of 1 and 4 was indicated. The antinociceptive action of 4 was linked to its anti-inflammatory activity.