Asian Journal of Chemical Sciences

Noncovalent And Host–guest Supramolecular Complexes in Nanomedicine: Self-healing Materials, Biomaterial Hydrogels, Bioimaging and Regenerative Medicine

Moh. Ali, Muhammad Zulfikar, Moch Kevin Alfian, Lailin El Safitri, Indana Zulfa — Fri, 16 Oct 2026 00:00:00 +0000

Supramolecular complexes assembled through noncovalent and host–guest interactions have become a central design strategy in nanomedicine, offering reversibility, stimuli-responsiveness and dynamic structural adaptation that covalent constructs cannot easily reproduce. This critical narrative review examines how four application areas, namely self-healing materials, injectable biomaterial hydrogels, bioimaging and regenerative medicine, have been shaped by a shared molecular toolkit comprising cyclodextrins, cucurbit[n]urils, pillar[n]arenes, calixarenes, hydrogen-bonded ureidopyrimidinone units and peptide assemblies. The analysis distinguishes well-supported conclusions from claims that remain preliminary. The quantitative relationship between host–guest binding thermodynamics, cross-link exchange kinetics and macroscopic material behaviour is now established across several independent platforms, and the capacity of dynamic networks to support injectability, cell infiltration and mechanotransduction is reproducibly demonstrated in vitro and in small-animal models. Translation diverges sharply across domains. Macrocyclic solubilising excipients and a cyclodextrin-based neuromuscular reversal agent have reached routine clinical use, and self-assembling peptide gels have entered controlled clinical testing for enamel remineralisation and endoscopic haemostasis, yet the self-healing, imaging and regenerative constructs that most fully exploit host–guest recognition remain almost entirely preclinical. Recurring weaknesses include heterogeneous and non-standardised reporting of self-healing efficiency, small and short-duration animal studies, uneven characterisation of in vivo complex stability, and persistent gaps in long-term immunological and clearance data for synthetic macrocycles. Pretargeted nuclear imaging using cucurbituril–adamantane pairs and xenon biosensors illustrates both the precision achievable and the distance still separating mechanistic elegance from clinical readiness. The evidence supports a measured conclusion: noncovalent supramolecular design is a mature conceptual framework with selective, not general, translational maturity. Progress now depends less on new host–guest chemistries than on standardised characterisation, larger and longer in vivo studies, and sustained attention to immunogenicity, degradation and reproducible manufacturing.

Synthesis, Spectroscopic Characterization, and Crystal Structure of a Mononuclear Mn(II) Complex Derived from the N'-(4-hydroxy-3-methoxybenzylidene) Isonicotinohydrazide Ligand: Evaluation of the Antioxidant Activity of the Ligand and Its Complex

Tue, 13 Oct 2026 00:00:00 +0000

A mononuclear manganese(II) complex of N′-(4-hydroxy-3-methoxybenzylidene)isonicotinohydrazide (H₂L) was synthesised and characterised to examine its structural features and DPPH radical-scavenging activity relative to the free ligand. The ligand was prepared by condensation of isonicotinic acid hydrazide with para-vanillin in ethanol, and the metal complex was obtained by reaction with manganese(II) chloride in methanol. Characterisation involved elemental analysis, infrared and electronic spectroscopy, molar conductivity measurements and single-crystal X-ray diffraction, with nuclear magnetic resonance spectroscopy also used for the ligand. Crystallographic analysis showed that the manganese(II) centre was coordinated by two pyridine nitrogen atoms from neutral ligand molecules and four oxygen atoms from water molecules, resulting in a distorted octahedral MnN₂O₄ environment. Spectroscopic findings were consistent with coordination through the pyridine nitrogen atoms. The radical-scavenging activity of both compounds was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Inhibition increased with concentration within the investigated range. The ligand exhibited inhibition values of 21.13 ± 0.17% to 53.62 ± 0.23%, whereas the complex exhibited values of 33.26 ± 0.34% to 61.66 ± 0.23%. The reported IC₅₀ values were 459 μM for the ligand, 310 μM for the complex and 493.36 μM for Trolox. Under the reported assay conditions, the complex exhibited greater DPPH radical-scavenging activity than the free ligand. Further stability and toxicity studies are necessary to assess the broader significance of these observations.

A Facile and Efficient Approach for the Synthesis of Novel 2-Azetidinone Derivatives and Their Biological Activities

M. S. More, B. G. Kharode, L.P. Shinde — Tue, 13 Oct 2026 00:00:00 +0000

Background: Substituted 2-azetidinones are of interest as β-lactam frameworks for synthetic and antibacterial investigations.

Aim: This study examined the synthesis, characterisation, antibacterial responses and predicted protein interactions of eight derivatives.

Methods: Schiff bases prepared from aromatic aldehydes and aromatic amines were cyclised using ketene obtained from acetyl chloride in the presence of triethylamine. The products, designated B1–B8, were purified, and spectroscopic data were reported using FT-IR and nuclear magnetic resonance techniques. Antibacterial responses were examined at concentrations of 1.0, 2.0 and 3.0 mg/mL against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Molecular docking against penicillin-binding protein 3 (PBP3; PDB ID: 8C5W) was undertaken using AutoDock Vina.

Results: Inhibition-zone diameters varied across compounds and concentrations, with several derivatives showing larger zones at higher concentrations. At 3.0 mg/mL, B2, B4 and B5 each produced 24 mm zones against E. coli; B2 produced a 25 mm zone against S. aureus; and B8 produced a 24 mm zone against P. aeruginosa. B2 showed the most negative reported docking score (−5.943 kcal/mol), while B7 yielded positive scores. Docking-box centres differed among compounds, limiting direct comparisons.

Conclusions: The findings describe the preparation of eight derivatives and preliminary antibacterial responses. Standardised docking, reconciliation of the reported analytical data, and additional quantitative biological testing are required to clarify the relative activities and possible mechanisms of these derivatives.

Determination of Some Molecular Properties of a Series of Primaquine Molecules with Antimalarial Activity by the DFT (Density Functional Theory) Method

Fri, 16 Oct 2026 00:00:00 +0000

This study evaluated selected molecular properties of five primaquine-derived compounds (PQ_1–PQ_5) with reported antimalarial activity using density functional theory (DFT). The investigation considered global chemical reactivity descriptors derived from frontier molecular orbitals, local reactivity indices, dipole moments, standard thermodynamic quantities of formation and lipophilicity. Molecular geometry optimisation and frequency calculations were performed in the gas phase at 298.15 K and 1 atm using the 6-311G(d,p) basis set. Local reactive sites were examined using Fukui functions and the dual descriptor, while lipophilicity was calculated using the Rekker fragmental method. The HOMO–LUMO energy gaps ranged from 3.4751 eV for PQ_5 to 3.9402 eV for PQ_1, identifying PQ_5 as the most chemically reactive and PQ_1 as the most chemically stable within the investigated series. Analysis of the local descriptors identified nitrogen atoms as preferred reactive sites for PQ_1, PQ_2 and PQ_4, whereas carbon and nitrogen sites differed for PQ_3 and PQ_5. All five molecules exhibited non-zero dipole moments (1.3706–2.7756 D) and positive calculated logP values (3.5030–5.1060), indicating polarity and lipophilicity. The calculated standard thermodynamic quantities of formation were negative for all compounds; PQ_2 exhibited the greatest thermodynamic stability by the criterion applied. These findings characterise differences within the selected series and provide a computational basis for subsequent experimental investigation.