Vitex Negundo–Fe3O4–CuO green nanocatalyst (VN–Fe3O4–CuO): synthesis of pyrazolo[3,4-c]pyrazole derivatives via the cyclization of isoniazid with pyrazole and their antimicrobial activity, cytotoxicity, and molecular docking studies

Abstract

In this study, we developed a novel pyrazolo[3,4-c]pyrazole derivative with antibacterial and antifungal activities that shows great potential for treating infectious diseases. To evaluate the binding affinity of 1AJ0 and 1AI9 proteins for developing potent antibacterial and antifungal compounds, we used the Vitex negundo (VN) leaf extract as the capping and reducing agent and reacted it with Fe₂O₃ and Cu(OAc)₂ solutions to synthesize the VN–Fe₃O₄–CuO nanocatalyst. The newly synthesized compounds were confirmed using Fourier transform infrared spectroscopy, transmission electron microscopy, UV-visible spectroscopy, and X-ray diffraction analyses. Antibacterial screening revealed that compound 1g was highly active against Escherichia coli (MIC: 1 μg mL⁻¹) and was much more effective than the standard ciprofloxacin. Compound 1b showed a higher antifungal activity than clotrimazole against Candida albicans (MIC: 0.25 μg mL⁻¹) and cytotoxic activity against MCF-7 cancer cell lines. Compounds 1a–1l were exhibited low cytotoxicity activity compared to the standard doxorubicin (LC₅₀: 21.05 ± 0.82 μg mL⁻¹). To further support the discovery of new active antibacterial agents, compounds 1g and 1b and proteins 1AJ0 and 1AI9 were examined using the AutoDock Vina program and were compared with the standards ciprofloxacin and clotrimazole. With the 1AJ0 protein, compound 1g had a higher docking score (−3.7 kcal mol⁻¹) than ciprofloxacin (−5.6 kcal mol⁻¹), and with the 1AI9 protein, compound 1b had a higher docking score (−4.8 kcal mol⁻¹) than clotrimazole (−4.4 kcal mol⁻¹). Additionally, molecular dynamics simulation was used to investigate the most probable binding mode of compounds 1b and 1g with 1AI9 and 1AJ0, respectively. The VN–Fe₃O₄–CuO catalyst was used to prepare pyrazolo[3,4-c]pyrazole derivatives, which were successfully characterized and screened for antimicrobial and cytotoxic activities, molecular docking, and molecular dynamics simulation studies.