Eco-friendly synthesis of an antimicrobial polymer (1, 4-bis(methacryloyl)piperazine) via maghnite catalysis: in vitro activity and in silico drug-likeness

Background – Poly (1, 4-bis(methacryloyl)piperazine) (poly (NBMP)) is a piperazine-based polymer with potential biomedical applications. Green clay catalysts, maghnite-H⁺ and maghnite-Na⁺; offer an eco-friendly approach for monomer (NBMP) and polymer (poly (NBMP)) synthesis with improved yields and low toxicity. Aim – To synthesize poly (NBMP) via green catalysis, evaluate its structural properties, and investigate its antimicrobial potential along with drug-likeness and molecular interaction profiles of its monomer. Method – The monomer and polymer were synthesized using varying amounts of maghnite-H⁺ and maghnite-Na⁺ at controlled temperatures. Structural characterization was performed using FTIR, ¹H and ¹³C NMR, SEM, and DSC. Antibacterial activity was tested against Gram-positive (S. aureus, L. monocytogenes) and Gram-negative bacteria (E. coli, P. aeruginosa, K. pneumoniae). Drug-likeness, toxicity predictions, molecular docking, and molecular dynamics (MD) simulations were conducted to assess binding affinities and complex stability of NBMP with the target bacterial proteins. Results – Monomer yield increased from 40% to 72% with 0–10 wt% maghnite-H⁺, while polymer yield rose from 5% to 70% using 0–15 wt% catalyst. Poly (NBMP) exhibited significant antibacterial activity, with inhibition zones of 32 μg/mL against S. aureus and 16 μg/mL against E. coli. Docking studies revealed moderate binding to K. pneumoniae FabG (PDB ID: 6T77, −6.1 kcal/mol). MD simulations confirmed stable complexes with RMSD values of 0.43 nm for E. coli DNA gyrase (PDB ID: 1KZN) and 0.19 nm for K. pneumoniae FabG, along with low RMSF and compact radius of gyration (0.04–0.07 nm). Discussion – The findings demonstrate that NBMP forms stable interactions with bacterial proteins, supporting its broad-spectrum antimicrobial activity. The eco-friendly synthesis, favorable drug-likeness, and structural stability highlight NBMP as a promising candidate for future biomedical applications. Further in vitro and in vivo studies are recommended to validate its therapeutic potential.