Search Results (711)

This study details how 3-(naphthalen-2-yl)-1-phenylprop-2-en-1-one (3NPEO) behaves in terms of photophysics when exposed to different solvents. The solvatochromic effect study reveals significant polarity shifts in the excited states of the 3NPEO compound, likely due to an intramolecular proton transfer mechanism. Measurements of dipole moments provide insight into their resonance structures in both ground and excited states. Electrochemical analysis revealed a reversible redox process, indicating a favorable charge transport potential. HOMO and LUMO energies of the compound were computed via oxidation and reduction potential standards. 3NPEO exhibits optimal one-photon and two-photon absorption characteristics, validating its suitability for visible wavelength laser applications in photonic devices. Furthermore, molecular docking and dynamics simulations demonstrated strong interactions between 3NPEO and the progesterone receptor enzyme, supported by structure–activity relationship (SAR) analyses. In vitro cytotoxicity assays on the MDAMB-231 breast cancer cell line showed moderate tumor cell inhibitory activity. Apoptosis studies confirmed the induction of both early and late apoptosis. These findings suggest that 3NPEO holds promise as a potential anticancer agent targeting the progesterone receptor in breast cancer cells. Overall, the findings highlight the substantial influence of solvent polarity on the photophysical properties and the design of more effective and stable therapeutic agents. Full article

Benzothiazole derivatives have emerged as being highly significant in drug discovery due to their versatile biological activities and structural adaptability. Incorporating nitrogen and sulfur, this fused heterocyclic scaffold exhibits wide-ranging pharmacological properties, including anticancer, antimicrobial, anti-inflammatory, antidiabetic, neuroprotective, and diagnostic applications. A diverse set of clinically approved and investigational compounds, such as flutemetamol for Alzheimer’s diagnosis, riluzole for ALS, and quizartinib for AML, illustrates the scaffold’s therapeutic potential in varied applications. These agents act via mechanisms such as enzyme inhibition, receptor modulation, and amyloid imaging, demonstrating the scaffold’s high binding affinity and target specificity. Advances in synthetic strategies and our understanding of structure–activity relationships (SARs) continue to drive the development of novel benzothiazole-based therapeutics with improved potency, selectivity, and safety profiles. We also emphasize recent in vitro and in vivo studies, including drug candidates in clinical trials, to provide a comprehensive perspective on the therapeutic potential of benzothiazole-based compounds in modern drug discovery. This review brings together recent progress to help guide the development of new benzothiazole-based compounds for future therapeutic applications. Full article

Type 2 diabetes mellitus (T2DM) demands safer and more effective therapies to control postprandial hyperglycemia. Here, we report the synthesis and in vitro evaluation of ten salicylic acid-derived Schiff base derivatives (4a–4j) as α-glucosidase inhibitors. Compounds 4e, 4g, 4i, and 4j exhibited potent enzyme inhibition, with IC₅₀ values ranging from 14.86 to 18.05 µM—substantially better than acarbose (IC₅₀ = 45.78 µM). Molecular docking and 500 ns molecular dynamics simulations revealed stable enzyme–ligand complexes driven by π–π stacking, halogen bonding, and hydrophobic interactions. Density Functional Theory (DFT) calculations and molecular electrostatic potential (MEP) maps highlighted key electronic factors, while ADMET analysis confirmed favorable drug-like properties and reduced nephrotoxicity. Structure–activity relationship (SAR) analysis emphasized the importance of halogenation and aromaticity in enhancing bioactivity. Full article

The recent global coronavirus pandemic highlighted the ever-present threat of respiratory virus outbreaks and the consequent need for ongoing research into antiviral therapy. To this end, structural analogues of the guanidinium-based drug camostat mesylate have been synthesised to probe their potential inhibition of Transmembrane Serine Protease 2 (TMPRSS2), a human protease that is essential for infection by many respiratory viruses, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Our in vitro fluorescence-based protease assays and supporting computational docking studies suggest that C-terminal camostat analogues retain TMPRSS2 inhibition potencies (IC₅₀ = 1–3 nM, BE = −6.6 to −7.0 kcal/mol) that match or exceed that of the parent drug. Analogues 1c and 1d emerge as lead candidates in this regard, thereby validating the rationale behind C-terminal structural modifications and highlighting these derivatives as promising scaffolds for the future development of targeted antiviral therapeutics. Replacement of camostat’s ester functionality with peptide linkages largely preserves non-covalent binding but disrupts in vitro protease inhibition, findings consistent with the parent drug’s known role as an acylating suicide inhibitor. Docking studies confirm that the replacement of aromatic residues with flexible, equivalent-length alkyl chains is detrimental to drug binding. These function and binding data offer new directions for the synthesis of further analogues of camostat and of other guanidinium-based protease inhibitors that have yet to be refined via structure–activity relationship studies. Further investigation will support tailoring this class of drugs for repurposing in antiviral therapy. Full article

Phage display has advanced the discovery of peptides that selectively bind to a wide variety of cell surface molecules, offering new modalities to modulate disease-related protein–protein interactions (PPIs). These cell-binding peptides occupy a unique pharmaceutical space between small molecules and large biologics, and their growing popularity has opened up new avenues for targeting cell surface proteins that were previously considered undruggable. This work provides an overview of methods for identifying cell-selective peptides using phage display combinatorial libraries, covering in vitro, ex vivo, and in vivo biopanning approaches. It addresses key considerations in library design, including the peptide conformation (linear vs. cyclic) and length, and highlights examples of clinically approved peptides developed through phage display. It also discusses the on-phage chemical cyclization of peptides to overcome the limitations of genetically encoded disulfide bridges and emphasizes advances in combining next-generation sequencing (NGS) with phage display to improve peptide selection and analysis workflows. Furthermore, due to the often suboptimal binding affinity of peptides identified in phage display selections, this article discusses affinity maturation techniques, including random mutagenesis and rational design through structure–activity relationship (SAR) studies to optimize initial peptide candidates. By integrating these developments, this review outlines practical strategies and future directions for harnessing phage display in targeting challenging cell surface proteins. Full article

Tuberculosis (TB) poses a persistent global health threat exacerbated by the emergence of drug-resistant strains; hence, there is a continuous quest for novel antimicrobial agents. Despite efforts to develop effective therapies, existing treatments require a relatively long duration of therapy to eradicate the pathogen due to its virulence factors, pathogenesis patterns, and ability to enter dormant states. This can lead to a higher risk of treatment failure due to poor patient adherence to the complex regimen. As a result, considerable research is necessary to identify alternative antituberculosis agents. The marine environment, particularly marine-derived fungi, has recently gained interest due to its potential as an abundant source of bioactive natural products. This review covers 19 genera of marine-derived fungi and 139 metabolites, 131 of which exhibit antimycobacterial activity. The integrated dataset pinpoints the fungal genera and chemical classes that most frequently yield potent antimycobacterial hits while simultaneously exposing critical gaps, such as the minimal evaluation of compounds against dormant bacilli and the presence of underexplored ecological niches and fungal genera. Several compounds exhibit potent activity through uncommon mechanisms, including the inhibition of mycobacterial protein tyrosine phosphatases (MptpB/MptpA), protein kinase PknG, ATP synthase and the disruption of mycobacterial DNA via G-quadruplex stabilization. Structure–activity relationship (SAR) trends are highlighted for the most potent agents, illuminating how specific functional groups underpin target engagement and potency. This review also briefly proposes a dereplication strategy and approaches for toxicity mitigation in the exploration of marine-derived fungi’s natural products. Through this analysis, we offer insights into the potency and challenges of marine-derived fungi’s natural products as hit compounds or scaffolds for further antimycobacterial research. Full article

The utilization of platinum complexes in medicine continues to be a prevalent treatment modality for diverse tumour types. However, it should be noted that certain platinum complexes are characterized by a high degree of toxicity. In recent years, there has been a focus among scientists on synthesizing “non-classic” platinum complexes, such as those with a trans-configuration, Pt(IV) complexes, and mixed ammine/amine platinum complexes, with the aim of reducing the toxic side effects of certain platinum complexes, including cisplatin. For instance, newly synthesized platinum complexes with a trans-configuration exhibited substantial cytotoxic activity which was comparable to that of the corresponding cis-isomers and cisplatin. This finding challenged the prevailing cis-geometry paradigm and prompted a re-evaluation of the structural activity relationships (SARs) of antitumour platinum complexes. It is widely accepted that Pt(IV) complexes act as prodrugs and release the active Pt(II) species. This property renders them promising candidates as anticancer drugs. Furthermore, it has been established that mixed ammine/amine platinum complexes are less toxic than cisplatin. In addition, compared to cisplatin, they have been observed to have equivalent or greater cytotoxic activity. Full article

Here we presented the synthesis of two groups of heterocyclic benzimidazole derivatives—methanimines 4a–c and hydrazones 6a–c. In vitro biological activity screening of the compounds was performed on isolated encapsulated muscle larvae of Trichinella spiralis. All tested compounds showed higher efficacy than albendazole, with compound 4a demonstrating activity comparable to ivermectin. Structure–activity relationship (SAR) analysis revealed that methanimines 4a–c, containing a thiophene moiety, were more effective than their hydrazone counterparts, highlighting the beneficial synergy between benzimidazole and thiophene pharmacophores. However, replacing the -N=CH- linker in compound 4a with -NH-N=CH- (as in compound 6a) led to a 23% reduction in activity, suggesting that methaniamines possess superior larvicidal potency under equivalent structural conditions. The ability of the studied compounds to interfere with the tubulin polymerization was studied spectrophotometrically on purified porcine brain. Of note, the tested benzimidazoles 4a–b and 6a–b had no discernible effect on tubulin polymerization. An in silico study of the physicochemical and pharmacokinetic characteristics of the novel synthesized heterocyclic benzimidazoles showed that they were characterized by a significant degree of drug-likeness and optimal properties for antineurotrichinellosis agents. Full article

Male contraception remains an unmet need. Na,K-ATPase α4 (NKA α4), a specific Na⁺/K⁺ transporter of the sperm flagellum, is an attractive target for male contraception. NKA α4 is critical for sperm motility and fertility, and its deletion in male mice causes complete infertility. Our previous structure–activity relationship (SAR) studies on a cardenolide scaffold identified a highly selective, safe NKAα4 inhibitor, but its complex, heavily hydroxylated structure posed challenges for modification and optimization. To address this, we employed a structural simplification strategy to synthesize novel steroidal and non-steroidal analogs and examined their effects on NKAα4 inhibition and sperm motility. Both series reduced sperm motility (up to ~50%), with IC₅₀ values in the picomolar range. Compounds 13 and 45 displayed specificities for NKAα4 over NKAα1, did not affect sperm viability, and showed no reversibility in vitro. Notably, 45, featuring a hexahydronaphthalene core and a benzyltriazole moiety at C5, exhibited potent, highly selective NKAα4 inhibition, reduced sperm motility in vitro and in vivo, and blocked fertilization in vitro. This highlights 45 as a promising lead for non-hormonal male contraception and indicates that the newly generated series of compounds possess the key characteristics needed for further development as potential non-hormonal male contraceptive agents. Full article

Sitophilus zeamais, a major pest of stored grains, causes significant post-harvest losses and challenges effective control. While synthetic insecticides pose risks of resistance and toxicity, essential oils (EOs) offer a safer alternative. However, the insecticidal potential of their individual volatile constituents (VCs) remains largely unexplored. This study evaluated the insecticidal activity of 51 EO-derived volatile compounds (VCs) against S. zeamais, identifying the most toxic ones, optimizing 15 synergistic mixtures, and assessing their effects on key insect enzymes. A structure–activity relationship (SAR) analysis determined functional groups associated with insecticidal activity, while a cluster analysis pre-selected 29 ternary mixtures, later refined using response surface methodology (RSM). Additionally, enzymatic assays explored their impact on detoxification and nervous system enzymes, providing insights into potential mechanisms of action. Among the 51 VCs tested, 37 exhibited significant toxicity, with 11 acting as fumigants and 13 displaying contact toxicity. Monocyclic monoterpenoids with ketone or alcohol functional groups and exocyclic unsaturation demonstrated the highest insecticidal activity via both exposure routes. Notably, pulegone enantiomers were particularly effective (LC₅₀ < 0.1 mg/L, LD₅₀ < 7.5 µg/adult). Among the optimized mixtures, 10 displayed strong insecticidal effects, 8 were active through both routes, and 5 exhibited synergistic fumigant interactions. The most effective formulations were M2 (R-pulegone + S-pulegone + S-carvone, LC₅₀ 0.48 mg/L) and M20 (isopulegone + δ-3-carene, LC₅₀ 2.06 mg/L), showing the strongest fumigant and synergistic effects, respectively. Enzymatic assays revealed that while some compounds mildly inhibited GST and CAT, others, such as δ-3-carene (IC₅₀ 0.19 mg/L), significantly inhibited AChE. Five mixtures exhibited synergistic neurotoxicity, with M20 (IC₅₀ 0.61 mg/L) and M12 (IC₅₀ 0.81 mg/L) emerging as the most potent AChE inhibitors. These findings highlight the potential of plant-derived volatile compounds as bioinsecticides, leveraging synergistic interactions to enhance efficacy, disrupt enzymatic pathways, and mitigate resistance. Full article

Background-Objectives: Chronic diseases linked to inflammation, such as cardiovascular disease (CVD) and cancer, continue to pose major public health challenges due to their high mortality rates. There is growing interest in natural bioactive compounds, particularly those derived from plants, as potential therapeutic or preventive agents due to their low toxicity profiles. This study aimed to explore two freshwater plants—Nelumbo nucifera (Indian lotus) and Lemna sp.—as potential sources of bioactive compounds with antioxidant, anti-inflammatory, and antithrombotic properties. While N. nucifera has established but incompletely characterized biofunctional properties, Lemna sp. remains largely unexplored in this context. Methods: Amphiphilic extracts from both plant species were analyzed for phenolic and lipid constituents, including unsaturated fatty acids, polar lipids, and carotenoids. Antioxidant capacity was evaluated using DPPH, ABTS, and FRAP assays. Anti-inflammatory and antithrombotic activities were assessed via platelet aggregation assays using PAF and ADP agonists. Structural characterization was performed using Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography–mass spectroscopy (LC-MS) to support structure–activity relationship (SAR) analysis. Results: Extracts, particularly from Lemna sp., showed potent antiplatelet activity against PAF and ADP. LC-MS revealed the presence of polar lipids rich in monounsaturated and omega-3 polyunsaturated fatty acids, with a favorable omega-6/omega-3 ratio, especially in Lemna sp., correlating with strong anti-inflammatory potential. High levels of total phenolics and carotenoids were observed, aligning with substantial antioxidant capacity in both species. Conclusions: These findings suggest that N. nucifera and Lemna sp. are promising sources of bioactive compounds with potential applications in functional foods, cosmetics, and pharmaceuticals targeting inflammation- and thrombosis-related chronic diseases. Further studies are warranted to confirm their safety and efficacy. Full article

Background/Objectives: Nucleoside precursors and derivatives play pivotal roles in the development of antimicrobial and antiviral therapeutics. The 2022 global outbreak of monkeypox (Mpox) across more than 100 nonendemic countries underscores the urgent need for novel antiviral agents. This study aimed to synthesize and evaluate a series of 5′-O-(palmitoyl) derivatives (compounds 2–6), incorporating various aliphatic and aromatic acyl groups, for their potential antimicrobial activities. Methods: The structures of the synthesized derivatives were confirmed through physicochemical, elemental, and spectroscopic techniques. In vitro antibacterial efficacy was assessed, including minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations for the most active compounds (4 and 5). The antifungal activity was evaluated based on mycelial growth inhibition. Density functional theory (DFT) calculations were employed to investigate the electronic and structural properties, including the global reactivity, frontier molecular orbital (FMO), natural bond orbital (NBO), and molecular electrostatic potential (MEP). Molecular docking studies were conducted against the monkeypox virus and the Marburg virus. The top-performing compounds (3, 5, and 6) were further evaluated via 200 ns molecular dynamics (MD) simulations. ADMET predictions were performed to assess drug-likeness and pharmacokinetic properties. Results: Compounds 4 and 5 demonstrated remarkable antibacterial activity compared with the precursor molecule, while most derivatives inhibited fungal mycelial growth by up to 79%. Structure-activity relationship (SAR) analysis highlighted the enhanced antibacterial/antifungal efficacy with CH₃(CH₂)₁₀CO– and CH₃(CH₂)₁₂CO–acyl chains. In silico docking revealed that compounds 3, 5, and 6 had higher binding affinities than the other derivatives. MD simulations confirmed the stability of the protein-ligand complexes. ADMET analyses revealed favorable drug-like profiles for all the lead compounds. Conclusions: The synthesized compounds 3, 5, and 6 exhibit promising antimicrobial and antiviral activities. Supported by both in vitro assays and comprehensive in silico analyses, these derivatives have emerged as potential candidates for the development of novel therapeutics against bacterial, fungal, and viral infections, including monkeypox and Marburg viruses. Full article

The expanding field of nutraceuticals and functional food science is increasingly turning to marine-derived bioactive compounds, particularly saponins, for their diverse pharmacological properties. These so-called thalassochemicals display distinctive structural features—such as sulfated glycosidic moieties and amphiphilic backbones—that underpin potent antitumor, hypolipidemic, antioxidant, and antimicrobial activities. In contrast to their terrestrial analogs, marine saponins remain underexplored, and their complexity poses analytical and functional challenges. This review provides a critical and integrative synthesis of recent advances in the structural elucidation, biological function, and technological application of marine saponins. Special emphasis is placed on the unresolved limitations in their isolation, characterization, and structural validation, including coelution of isomers, adduct formation in MS spectra, and lack of orthogonal techniques such as NMR or FTIR. We illustrate these limitations through original MS/MS data and propose experimental workflows to improve compound purity and identification fidelity. In addition to discussing known structure–activity relationships (SARs) and mechanisms of action, we extend the scope by integrating recent developments in computational modeling, including machine learning, molecular descriptors, and quantitative structure–activity relationship (QSAR) models. These tools offer new avenues for predicting saponin bioactivity, despite current limitations in available high-quality datasets. Furthermore, we include a classification and comparison of steroidal and triterpenoid saponins from marine versus terrestrial sources, complemented by detailed chemical schematics. We also address the impact of processing techniques, delivery systems, and bioavailability enhancements using encapsulation and nanocarriers. Finally, this review contextualizes these findings within the regulatory and sustainability frameworks that shape the future of saponin commercialization. By bridging analytical chemistry, computational biology, and food technology, this work establishes a roadmap for the targeted development of marine saponins as next-generation nutraceuticals and functional food ingredients. Full article

Flavone derivatives have emerged as promising antiviral agents, with baicalein demonstrating the potent inhibition of the SARS-CoV-2 main protease (Mpro). In this study, the unique electronic and structural properties of 3-hydroxyflavone (3-HF) were investigated using the density functional theory (B3PW91/cc-pVTZ), providing insights into its potential as a bioactive scaffold. Among mono-hydroxyflavone (n-HF) isomers, 3-HF exhibits an extensive intramolecular hydrogen-bonding network linking the phenyl B-ring to the A- and γ-pyrone C-rings, enabled by the distinctive C3-OH substitution. Despite a slight non-planarity (dihedral angle: 15.4°), this hydrogen-bonding network enhances rigidity and influences the electronic environment. A ¹³C-NMR chemical shift analysis revealed pronounced quantum mechanical effects of the C3-OH group, diverging from the trends observed in other flavones. A natural bond orbital (NBO) analysis highlighted an unusual charge distribution, with predominantly positive charges on the γ-pyrone C-ring carbons, in contrast to the typical negative charges in flavones. These effects impact C1s orbital energies, suggesting that the electronic structure plays a more significant role in ¹³C-NMR shifts than simple ring assignments. Given the established antiviral activity of hydroxylated flavones, the distinct electronic properties of 3-HF may enhance its interaction with SARS-CoV-2 Mpro, making it a potential candidate for further investigation. This study underscores the importance of quantum mechanical methods in elucidating the structure–activity relationships of flavones and highlights 3-HF as a promising scaffold for future antiviral drug development. Full article

Osthole is a natural coumarin-like compound isolated from the Fructus cnidii. In the last few years, this plant-derived product and its derivatives have aroused much attention for their interesting biological activities, including anticancer, anti-inflammatory, neuroprotective, and insecticidal effects. This review summarizes the recent progress on the biological activities of osthole and its derivatives from 2018 to early 2025, with a focus on their total synthesis, structural modifications, and mechanisms of action. Additionally, structure–activity relationships (SARs) of osthole derivatives are presented. This review aims to serve as a comprehensive reference for future research on osthole and its derivatives in both medicinal and agricultural applications. Full article