Search Results (706)

A series of nucleolipid derivatives based on adenosine and 1,N⁶-ethenoadenosine was synthesized, and their cytotoxicity was evaluated in glioma and glioblastoma cell models. Twenty O-2′,3′-ketalized nucleolipid derivatives were prepared as symmetric and asymmetric adenosine analogs. The lipophilicity was determined using the octanol/water partition method, yielding logP_OW values from −0.04 to 4.08. First, cytotoxicity was screened in rat/human glioma cell lines (BT4Ca/GOS-3) using a PrestoBlue™ viability assay, with 5-fluorouridine (5-FUrd) as the reference compound. Selected derivatives with the highest cytotoxicity were evaluated in human glioblastoma cell lines U87 and U251, and their efficacy was compared with the chemotherapeutic agent temozolomide (TMZ). PMA-differentiated human THP-1 macrophages were used to assess cytotoxic side effects in human immune-related cells. Several derivatives induced 90–100% cytotoxicity at 50 µM after 48 h, with cytotoxicity increasing with alkyl chain length and reaching a maximum for derivatives bearing medium-length chains (C₁₅–C₁₇). In contrast, shorter or longer chains caused reduced activity. Cytotoxicity was independent of symmetric or asymmetric ketal configuration, while 1,N⁶-ethenoadenosine ketal derivatives displayed higher activity than the corresponding adenosine ketals. These novel derivatives indicate that lipophilicity and alkyl chain length are responsible for the cytotoxic effect in glioma and glioblastoma, and that they are more effective than 5-FUrd and TMZ. Full article

Background: Glioblastoma (GBM) remains a lethal malignancy due to temozolomide (TMZ) resistance and limited drug penetration across the blood–brain barrier, largely driven by hyperactive DNA damage repair mechanisms such as poly (ADP-ribose) polymerase (PARP). To address these challenges, we developed folic acid-targeted PLGA–zein hybrid core–shell nanoparticles for the codelivery of the alkylating agent TMZ and the natural PARP inhibitor Ellagic acid (FA-TMZ/EA-PZ-CS NPs), thereby enabling simultaneous enhancement of drug delivery and suppression of chemoresistance pathways. Methods and Results: The dual-drug nanoplatform was fabricated using a double-emulsion solvent evaporation method and functionalized via EDC/NHS-mediated folic acid conjugation to promote receptor-mediated uptake. Physicochemical characterisation confirmed uniform spherical morphology, high colloidal stability, efficient drug encapsulation, and sustained biphasic drug release consistent with a core–shell diffusion mechanism. In LN229 glioblastoma cells, folic acid conjugation significantly enhanced cellular internalisation and cytotoxic efficacy compared to free drugs and non-targeted nanoparticles. Combination index analysis revealed strong synergism between TMZ and ellagic acid, resulting in markedly reduced IC₅₀ values. Mechanistic studies demonstrated apoptosis induction, increased DNA damage, inhibition of cell migration at sub-cytotoxic concentrations, and downregulation of PARP gene expression. Conclusion: Overall, this study establishes a targeted core–shell nanotherapeutic strategy that integrates chemotherapy with DNA repair inhibition to overcome TMZ resistance, offering a mechanistically sound strategy that serves as a foundational framework for future translational research. Full article

As a devastating disease worldwide, rice bacterial leaf blight—caused by Xanthomonas oryzae pv. oryzae (Xoo)—leads to substantial reductions in grain yield. The increasing resistance to conventional bactericides necessitates the development of novel and sustainable control agents. This study evaluated 58 novel alkyl sulfonamide compounds against Xoo. In the turbidimetric assay at 100 mg/L, several compounds showed potent antibacterial activity. Among them, SYAUP-116 and SYAUP-212 exhibited in vitro inhibition comparable to that of streptomycin sulfate at the same concentration. Furthermore, in EC₅₀ determination assays, both compounds yielded lower EC₅₀ values than zinc thiazole. Among the 58 compounds tested, SYAUP-491 exhibited an in vitro EC₅₀ of 6.96 mg/L and achieved 74.1% in vivo therapeutic efficacy at 200 mg/L, representing the most promising lead for further characterization. Molecular docking, based on prior proteomic data, indicates potential stable binding to ribosomal proteins (50S L33/L34 and 30S S5), with the strongest interaction observed for L33 (binding free energy: −5.73 kcal/mol). This suggests a putative mechanism involving ribosome targeting and protein synthesis inhibition, which may be facilitated by hydrophobic interactions and halogen bonds derived from its trifluoromethyl and sulfonamide groups. SYAUP-491 demonstrates significant potential as a novel bactericide for rice bacterial leaf blight, warranting further research on structure-activity optimization, target validation, and field performance. Full article

Coal gasification fine ash (CGFA) is a carbon–mineral composite solid waste whose valorization is severely hindered by poor interfacial compatibility with organic media due to its highly polar surface. Here, we report a surface alkylation strategy using haloalkanes with variable chain lengths to systematically tune the surface chemistry and thermo-oxidative behavior of CGFA. Comprehensive spectroscopic characterizations (XPS, FTIR, and ¹³C NMR) confirm successful grafting of alkyl chains, which increases aliphatic C-H content from 24.8% to 43.9% while reducing polar carboxyl groups from 7.9% to 1.6%, with the mineral framework remaining intact. Thermogravimetric analysis reveals that alkylation lowers the onset decomposition temperature from 358 °C to 295 °C and enhances the maximum mass-loss rate. Kinetic analysis shows that grafted alkyl chains act as low-energy initiation sites, reducing the initial activation energy to 95 kJ/mol, while the later-stage oxidation becomes diffusion-limited. Notably, long straight-chain alkylation achieves the best performance, whereas branched chains are less effective due to steric hindrance and pore blockage. This work establishes a clear chain-length-dependent structure–thermal response relationship, positioning alkylated CGFA as a designable precursor for functional carbon materials, intelligent char-forming agents, and tunable components for energy or responsive material systems. Full article

Despite transformative therapeutic advances, multiple myeloma (MM) remains an incurable malignancy characterized by sequential relapses and progressive treatment resistance. Patients with heavily pretreated relapsed or refractory MM continue to face limited therapeutic options and poor outcomes. Melflufen (melphalan flufenamide) is a peptide–drug conjugate that enhances intracellular delivery of alkylating agents via aminopeptidase-mediated activation. Early clinical studies demonstrated encouraging activity in advanced MM, leading to accelerated approval by the U.S. Food and Drug Administration in 2021. However, results from the phase III OCEAN trial raised concerns regarding overall survival, ultimately resulting in withdrawal of the drug from the U.S. market. In this review, we examine the biological rationale, clinical development, and regulatory trajectory of melflufen, and critically reassess its role within the evolving therapeutic landscape of MM. While the negative survival findings observed in the phase III OCEAN trial substantially limited the clinical development of melflufen, the biological principles underlying enzyme-targeted intracellular drug delivery may still provide relevant insights for biomarker-driven therapeutic strategies and future peptide–drug conjugate development in MM. Full article

Background/Objectives: The widespread emergence of chloroquine-resistant Plasmodium falciparum continues to drive the search for new quinoline-based antimalarial agents capable of retaining efficacy against resistant parasites. This study aimed to evaluate a series of synthetic quinoline derivatives incorporating arylnitro and aminochalcone moieties for their antiplasmodial activity and selectivity. Methods: A series of eighteen synthetic quinoline derivatives were evaluated for in vitro antiplasmodial activity against P. falciparum strains (3D7, K1, and Dd2), along with cytotoxicity in mammalian cells and hemolytic activity in human red blood cells. Structure–activity relationship analysis was performed, and molecular docking studies were conducted against β-hematin and the chloroquine resistance transporter (PfCRT). Results: Several compounds exhibited sub-micromolar activity against the chloroquine-sensitive 3D7 strain. The most potent compound (Compound 14), a nitro-substituted N-alkylated quinoline bearing a CF₃-enriched aromatic chalcone framework, demonstrated high potency and selectivity (IC₅₀ = 0.13 μM; SI = 1132.92). Importantly, this compound retained substantial activity against multidrug-resistant K1 and Dd2 strains, displaying lower resistance indices than chloroquine. Structure–activity relationship analysis revealed that nitro substitution, N-alkylation, and halogen/CF₃-rich aromatic features critically influence potency and selectivity. Docking studies suggested that Compound 14 engages both β-hematin and PfCRT more extensively than chloroquine. Conclusions: These findings identify Compound 14 as a promising lead scaffold for further optimization toward next-generation antimalarial agents. Full article

A novel series of hybrid tetrahydro-β-carboline (THβC)-imidazolium (IM) salts incorporating a fused diketopiperazine scaffold was designed, synthesized, and evaluated as cholinesterase inhibitors for potential application in Alzheimer’s disease. The molecular design integrates a π-conjugated THβC core with a cationic IM moiety to promote dual-site interactions within the acetylcholinesterase (AChE) active-site gorge. All compounds exhibited micromolar inhibitory activity against AChE and butyrylcholinesterase (BChE), with a pronounced preference for AChE. The most active derivative, 12d, showed an IC₅₀ value of 0.72 μM toward AChE, while compound 12c demonstrated the highest selectivity (SI = 8.4). Structure–activity relationship studies revealed that both stereochemistry and N-alkyl chain length are critical determinants of activity, with S,S-configured derivatives consistently outperforming their R,R-configured analogs. In silico ADMET analysis indicated favorable physicochemical properties and predicted central nervous system permeability, although potential hepatotoxicity highlights the need for further optimization. Molecular docking studies suggested that the most promising compound adopts a dual-binding mode, interacting with both the peripheral anionic site and catalytic active site of AChE. These results identify THβC-IM hybrids as a structurally novel and promising scaffold for the development of selective cholinesterase inhibitors, providing a basis for further optimization toward multifunctional anti-Alzheimer agents. Full article

The introduction of amine groups into the four-membered central ring of squaraine dyes is expected to enhance the intrinsic cytotoxicity of this scaffold. In this study, the biological effects of eight benzothiazole-based aminosquaraine dyes were investigated by varying the length of the N-alkyl chains and the nature of the introduced amine. Biological activity was evaluated through different assays in several cell lines, including apoptosis and cell cycle analysis, as well as confocal microscopy studies. Overall, the incorporation of amino, methylamino, and ethanolamino groups significantly increased cytotoxicity, with the corresponding dyes displaying low half-maximal inhibitory concentration values, in some cases even lower than that of the positive control, 5-fluorouracil. In contrast, derivatives bearing diethanolamino or ethylenediamino groups exhibited lower cytotoxicity, particularly the dye containing N-decyl chain. For the dyes selected for further investigation, bearing a methylamino group and N-butyl or -hexyl chains, the induction of apoptosis was evident, especially for methylaminosquaraine dye 3. These dyes also exhibited antiproliferative effects, as evidenced by their ability to induce cell cycle arrest. Confocal microscopy revealed a predominantly cytoplasmic distribution, likely associated with cytoplasmic organelles, with limited penetration into the nucleus. Overall, although squaraines are widely recognized as promising photodynamic agents, the present results suggest that they may also be explored in chemotherapeutic approaches, particularly when exhibiting high intrinsic cytotoxicity. Full article

A series of hexadecylpiperidinium surfactants containing alkyl (PMe-16, PEt-16, PBu-16), benzyl (Benz-16, 1-Benz-3-HP-16, 1-Benz-4-HP-16), and hydroxyl (3-HPMe-16, 4-HPMe-16) substituents in the ring were tested with the nematode Caenorhabditis elegans to investigate the relationship between nematocidal activity and the structural features of surfactants. It was found that increasing the hydrophobicity of the substituent in the surfactant head group reduced the nematocidal activity in the order PMe-16 > PEt-16 > PBu-16 > Benz-16. The lead compound, PMe-16, showed significantly higher activity than the commercial insecticide carbofuran, and was able to induce nearly complete nematode mortality within 24 h at a concentration of 50 μg·mL⁻¹, as well as suppress culture development at concentrations of 25–100 μg·mL⁻¹. All tested piperidinium surfactants inhibited nematode population development at 100 μg·mL⁻¹, while PMe-16 remained effective at concentrations as low as 25 μg·mL⁻¹. The membranotropic properties of the surfactants were evaluated using a turbidimetric method with dipalmitoylphosphatidylcholine (DPPC)-based liposomes as a model of biomembranes. Dynamic light scattering measurements were performed in parallel to assess changes in liposome size and zeta potential as a function of surfactant content, as well as to determine the critical concentration required to induce lipid bilayer destabilization. These results provide indirect evidence of surfactant–membrane interactions. The combinations of piperidinium surfactants and carbofuran showed pronounced synergistic effects, reducing the insecticide dose while maintaining efficacy. Synergy was evaluated using the Bliss independence model and the Highest Single Agent model. The addition of the most active surfactants (PMe-16 and 4-HPMe-16) at 6.25 μg·mL⁻¹ enabled an approximately twofold reduction in the carbofuran dose while maintaining full nematocidal activity. Full article

Glioblastoma (GB) classical treatment with the alkylating drug temozolomide (TMZ) is not effective mainly due to chemoresistance mechanisms, particularly those mediated by O6-methylguanine-DNA methyltransferase (MGMT). In this context, polyethylene glycol (PEG)-coated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were developed to deliver tamoxifen (TAX), a clinically approved non-alkylating drug with reported anti-GB activity. The NP formulation was optimized using a factorial design and subsequently functionalized with lactoferrin (Lf) to enhance GB targeting. The Lf-conjugated optimized formulation exhibited a mean diameter of 193 ± 6 nm, a polydispersity index (PDI) of 0.11 ± 0.04, a zeta potential of −18.2 ± 6.8 mV, and an encapsulation efficiency (EE) of 68.6 ± 1.8%. The NPs exhibited a sustained release profile for up to 23 days, and remained stable under physiological conditions. Cell uptake studies, conducted in human GB cells (U87, U251, and T98G) and healthy astrocytes, demonstrated enhanced internalization of Lf-NPs in GB cells compared with non-conjugated NPs, suggesting uptake through Lf-binding site-mediated endocytosis. Cytotoxicity assays further indicated that Lf-conjugation improved the antiproliferative efficacy of TAX-loaded NPs relative to non-functionalized formulations, particularly in GB cells. Moreover, combination studies with TMZ showed that the developed NPs were able to sensitize GB cells to treatment with this alkylating agent. In sum, this work supports the potential of the developed Lf-decorated TAX-loaded PLGA NPs as a nanoplatform for targeted delivery against GB. Full article

Multidrug (MDR) resistances against various classes of antibiotics used in S. aureus and MRSA infections have emerged. With limited options for novel antibacterial compounds, there is a strong focus on finding agents against MDR phenomenon, namely causative efflux pumps. We synthesised novel benzo-annelated 1,4-dihydropyridines with various substitution patterns both at the 4- and N-alkyl substituents and, additionally, at the annelated aromatic residues. MDR efflux pump-inhibiting activity was evaluated in S. aureus strains including MRSA and was measured in a fluorescent assay system using ethidium bromide as the overall substrate of S. aureus efflux pumps. Favourable substituents for inhibiting efflux pump activity in S. aureus have been 4-methoxy and 4- and 3-chloro at the 4-phenyl position of the 1,4-dihydropyridine ring combined with an N-benzyl residue. The most favourable substituents for the activity inMRSA strains have been those 4-phenyl chloro substituents combined with additional pyrido residues attached to the benzo substituent at the 1,4-dihydropyridine core. Benzo-annelated 1,4-dihydropyridines are a novel class of inhibitors of MDR relevant efflux pumps in S. aureus strains including MRSA. Full article

In the treatment of atopic dermatitis (AD), synergistic activation of the aryl hydrocarbon receptor (AHR)/nuclear factor erythroid 2-related factor 2 (NRF2) pathways represents a promising strategy. However, known dual agonists are limited, and traditional screening methods are inefficient. Therefore, this study developed machine learning models to predict AHR/NRF2 dual agonists using molecular descriptors and fingerprints. All models achieved area under the receiver operating characteristic curve (AUC) values above 0.86, indicating good classification performance. The optimal AHR model showed an accuracy (ACC) of 0.811 and an AUC of 0.878, while the best NRF2 model yielded an ACC of 0.839 and an AUC of 0.907. Based on this model, compounds with a low fraction of sp³-hybridized carbons, moderate hydrophobicity, limited alkyl chains, and highly conjugated structures tend to act as AHR/NRF2 dual agonists. Finally, this study screened 1011 potential natural AHR/NRF2 dual agonists suitable for drug development. Among these, 2-arylbenzofurans, alkaloids, phenanthrenes, flavones, and furocoumarins demonstrated particular advantages. For validation, Indirubin, imperatorin and 3′-O-Methylbutastatin III were first discovered as AHR/NRF2 dual agonists in HaCaT cells. This work provides a robust predictive tool, clarifies key molecular features of dual agonists, and may support the discovery of anti-AD agents. Full article

Aloe-emodin is an anthraquinone with a wide range of medicinal applications, including anti-angiogenic, anticancer, antimicrobial, antiviral, anti-inflammatory, and antioxidant activities. In this review, the functionalization of aloe-emodin using various synthetic methods, including alkylation, condensation, esterification, the Finkelstein reaction, and the Kabachnik–Fields reaction was reported. The biological activity of the synthesized aloe-emodin derivatives is discussed, with a focus on their potential future applications as anticancer agents, enzyme inhibitors, anti-inflammatory agents, and antimicrobial agents. This review also discusses the structure–activity relationship (SAR) and the mechanism of action (e.g., molecular docking studies, cell membrane-disrupting capacity, and apoptosis studies). This review highlights the many contributions made towards the design and development of novel, biologically active aloe-emodin derivatives. Full article

This study investigated the structural and anti-inflammatory properties of Zophobas morio lipids (ZMLs). The fatty acid (FAs) composition showed a higher proportion of unsaturated FAs, mainly consisting of oleic (30.30%) and linoleic acids (20.05%), than saturated FAs, including palmitic (24.80%) and stearic acids (12.96%). In addition, FT-IR and ¹H-NMR analyses confirmed that ZML possessed a typical triglyceride structure, with long-chain alkyl groups. Thermogravimetric analysis (TGA) indicated that ZML exhibited high thermal stability, with a degradation peak at 369 °C. Differential scanning calorimetry (DSC) displayed a thermal transition at −8 °C, corresponding to the crystallization of unsaturated FAs in ZML. ZML significantly inhibits lipopolysaccharide (LPS)-induced pro-inflammatory M1 macrophage polarization by suppressing nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, thereby attenuating the expression of inflammatory mediators. Additionally, ZML alleviated inflammatory oxidative stress by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant pathway. Notably, ZML not only induced M2 macrophage polarization in quiescent macrophages but also reprogrammed M1 macrophages toward the anti-inflammatory M2 phenotype. These findings suggest that ZML is a natural nutritional lipid source and a potential therapeutic agent for modulating inflammatory response. Full article

Synthetic derivatives of testosterone known as 17α-alkylated anabolic–androgenic steroids have been developed to retain anabolic effects while enabling oral administration. Here, we present newly identified hydrated solid forms of three agents: oxandrolone hemihydrate (C₁₉H₃₀O₃·0.5H₂O), fluoxymesterone hydrate (C₂₀H₂₉FO₃·H₂O), and methandienone hemihydrate (C₂₀H₂₈O₂·0.5H₂O). Their crystal structures were determined using single-crystal X-ray diffraction, supplemented by powder X-ray diffraction and thermal analyses. Computational methods were employed to investigate molecular interactions and crystal packing. Lattice energy evaluations revealed that the hydrated forms are energetically less stable than their anhydrous counterparts, with significantly less negative values (e.g., −113.4 kJ/mol for oxandrolone hemihydrate vs. −164.4 kJ/mol for the anhydrous form). Energy decomposition analysis indicates that while water molecules participate mostly in electrostatic-driven hydrogen bonding, they disrupt the dispersive packing efficiency found in the anhydrous phases. Specifically, intermolecular interaction energies show that host–host hydrogen bonds (up to −62.2 kJ/mol in oxandrolone) dominate over weaker host–water couplings (−8.9 to −34.9 kJ/mol). The newly reported crystal structures contribute to the expanding catalog of solid-state forms for 17α-alkylated steroids and provide important details regarding their metastable nature and the dehydration-driven phase transformations observed under climatic stress conditions. Full article