Design, Biological Evaluation, and Zebrafish Embryo Toxicity of a Novel Pyrazoline Derivative

Background: Pyrazoline derivatives have significant medicinal use for their diverse pharmacological activities. Zebrafish embryos are mostly used in toxicity studies due to its transparency, rapid development and genetic similarity to humans. Fish Embryo Toxicity Test provides rapid, ethical and resource efficient screening. This study aimed to synthesize and evaluate a novel pyrazoline derivative for antibacterial, cytotoxic, and toxicity properties. Materials and Methods: The compound 3-(1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-yl)-2-m ethoxyphenol, was synthesized through a multi-step Mannich reaction and characterized using FT-IR, NMR and Mass spectrometry. Drug likeness and pharmacokinetic parameters were predicted with Molinspiration, OSIRIS, and SwissADME software’s. Molecular docking targeted Topoisomerase II and DNA gyrase. Antibacterial activity was tested against E. coli, P. aeruginosa and S. aureus. Cytotoxicity effect against Dalton’s Lymphoma Ascites cells and Zebrafish Embryo Toxicity (OECD 236) was evaluated for its toxicity. Results: Computational prediction shows favourable drug-likeness and adherence to Lipinski’s five rules. Docking studies demonstrated substantial binding affinities: -8.14 kcal/mol and -7.28 kcal/mol for Topoisomerase II and DNA gyrase respectively. The compound exhibited potent anti-bacterial activity with inhibition zone ranging from 12 to 17 mm at 100 μg/mL. Cytotoxicity assay revealed dose-dependent increase in cell death, reaching 86.3±2.0% at 200 μg/mL. Zebrafish embryo toxicity assay revealed developmental abnormalities at 50 μg/mL and 25 μg/mL, with an LC50 of 18.75 μg/mL. Conclusion: The compound exhibited favourable pharmacokinetic properties, suggesting its potential as an antibacterial and cytotoxic agent. However, Zebrafish Embryo toxicity highlights the need for further development and in-depth evaluation before it can as a therapeutic candidate.