Structure and toxicity of N-donor thionate Zn complexes

Array of Manganese-Based Bimetallic Metal-Organic-Framework Nanozymes with Enhanced Oxidase-like Catalytic Activity Can Simultaneously Identify and Measure Antioxidants

Developing sensitive and highly active nanozymes for antioxidant analysis is of the utmost significance in medical diagnosis and health monitoring due to their essential roles as free reactive oxygen species scavengers. Here, six metal-organic frameworks (MOFs)-based nanozymes are developed as a dual-mode absorbance/image analysis colorimetric sensor array for simultaneous discrimination and determination of various antioxidants with comparable structural or chemical properties. The catalysts exhibit a wide range of highly potent oxidase-like catalytic activities, as verified by kinetic parameters, due to the presence of highly dispersed transition metallic and bimetallic redox nodes. These nanozymes efficiently catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMBox, resulting in noticeable absorption and RGB color changes at 650 nm. Various antioxidants demonstrate different reducing capabilities to TMBox, leading to the generation of fingerprint-like spectral color patterns. The pattern recognition chemometrics methods including principal component analysis (PCA) and linear discriminant analysis (LDA) represent well-separated clustering and discrimination of ascorbic acid, dopamine, uric acid, cysteine, glutathione, thiocyanate, tannic acid, and gallic acid. The colorimetric assay provides a wide linear detection range (0.1-75 μM) and detection limits as low as 30 nM. The sensor array successfully discriminated antioxidants of various concentrations, mixtures, and potent interferences. Furthermore, the sensor's applicability in biologically relevant detection was validated in urine and plasma samples. Overall, the MOF-based nanozyme sensor array offers a promising platform for discriminating and determining a wide range of antioxidants with potential applications.

Experimental and Computational Investigation of Cu(II) and Zn(II) complexes: DFT, Docking, and Anti-Lung Cancer Studies

AIMS

This study aimed to synthesize and characterize a Schiff base ligand, (Z)-2-(2-oxoindolin-3-ylidene)hydrazinecarbothioamide (1), and its copper(II) (2) and zinc(II) (3) complexes, as well as evaluate their binding interactions with the epidermal growth factor receptor (EGFR) and anticancer activity against the human lung cancer A549 cell line.

MATERIALS & METHODS

The Schiff base ligand was synthesized by refluxing isatin and thiosemicarbazide for 3 hours. Complexes 2 and 3 were formed and characterized using elemental analysis, molar conductivity, IR, NMR, and UV-Visible spectroscopy. The geometry of complex 3 was determined via X-ray diffraction. Theoretical calculations were conducted using DFT with the hybrid GEN B3LYP method. Molecular docking was performed to assess binding energies with EGFR, and anticancer activity was evaluated against the A549 cell line.

RESULTS

Characterization confirmed successful synthesis of the compounds. Zinc complexation led to notable spectral shifts, and X-ray diffraction revealed complex 3 adopted a distorted tetrahedral geometry. DFT analysis highlighted complex 2 with the lowest energy gap (0.331 eV). Docking results showed strong EGFR binding energies (-5.70, -5.54, and -7.30 kcal/mol). Complex 2 demonstrated the highest anticancer efficacy with a cell viability of 1.35% after 48 h.

CONCLUSIONS

Complex 2 exhibits significant anticancer potential and warrants further investigation as a therapeutic agent.