Unveiling the cyclopropyl appended acyl thiourea derivatives as antimicrobial, α-amylase and proteinase K inhibitors: Design, synthesis, biological evaluation, molecular docking, DFT and ADMET studies

Acyl thiourea scaffolds are frequently employed in drug development to discern unique and essential therapies for the eradication of the most challenging diseases. Hence, we developed a library of novel cyclopropyl incorporating acyl thiourea derivatives (4a-j) and evaluated their antimicrobial, α-amylase, and proteinase K inhibition potential. Compound (4h) (4-methoxy) demonstrated the strongest α-amylase inhibition (IC₅₀ = 1.572 ± 0.017 μM), while compound (4j) (3,4,5-trimethoxy) exhibited potent proteinase K inhibition (IC₅₀ = 1.718 ± 0.061 μM), comparable to the standard acarbose (IC₅₀ = 1.063 ± 0.013 μM) and phenyl methyl sulfonyl fluoride (IC₅₀ = 0.119 ± 0.014 μM). The unsubstituted compound (4a) emerged as the most potent antifungal agent (17 mm zone of inhibition), outperforming the positive control Terbinafine (zone of inhibition 16 mm). These compounds (4a-j) also displayed moderate antibacterial activity. SAR analysis revealed the influences of various substitutions on the acyl thiourea scaffold. Computational studies, including DFT, molecular docking, and ADMET predictions, supported the biological findings and identified these compounds as promising inhibitors of α-amylase, proteinase K, and microbial pathogens.