Design, synthesis, and antimicrobial activity of new thiourea-uracil derivatives: Anti-biofilm, ROS, DHFR, computational and SAR studies.

A new series of thiourea derivatives bearing uracil ring was synthesized. The reaction of 5-amino uracil with isothiocyanate derivatives afforded the corresponding thiourea-uracil derivatives in excellent yields. The antimicrobial activity of the synthesized thiourea-uracil derivatives was successfully determined against different pathogen types. Interestingly, some derivatives such as TUU-05 and TUU-08 show a potent impact on microbial proliferation with a notable MIC value, particularly in the case of Aspergillus niger (7.5 ± 2.11 μg/mL). Accordingly, compound TUU-08 was considered a promising antimicrobial agent that could release elevated Reactive Oxygen Species (ROS) and inhibit the bacterial Dihydrofolate Reductase (DHFR) enzyme at lower IC50 (7.29 ± 0.02 μM) compared with methotreaxat (IC50 = 6.55 ± 0.05 μM). Molecular docking analyses revealed that the most active compounds TUU-01, TUU-02, and TUU-08 exhibited strong binding affinities and targeted interactions with key antimicrobial-associated enzymes: Aspergillus niger, Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Molecular docking analyses revealed that the most active compounds TUU-01, TUU-02, and TUU-08 exhibited strong binding affinities and targeted interactions with key antimicrobial-associated enzymes: Aspergillus niger, Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Computational ADMET profiling further indicated that TUU-01, TUU-02, and TUU-08 adhered to Pfizer's drug-likeness criteria, displaying favorable physicochemical properties, high predicted oral bioavailability and low toxicity risks. Molecular dynamics simulations corroborated the stability of these interactions, particularly for TUU-02, which showed RMSD values of 0.35-0.55 nm (A. niger), 0.25-0.35 nm (C. albicans), 0.20-0.25 nm (P. aeruginosa), and 0.18-0.25 nm (S. aureus), alongside moderate structural flexibility (RMSF: 0.10-0.9 nm). Additional metrics-including solvent-accessible surface area (SASA: 200-230 nm2, 85-95 nm2, 125-135 nm2, 130-140 nm2) and radius of gyration (Rg: 2.2-2.4 nm, 1.80-1.90 nm, 1.55-1.60 nm, 1.80-1.90 nm) highlighted the compactness and solvent interaction profiles of the complexes.