Antimicrobial, antibiofilm, and molecular docking evaluation of silver nanoparticles biosynthesized from Ocimum campechianum against Staphylococcus spp

Antimicrobial resistance and the overuse of antimicrobials have driven the search for innovative therapies, particularly those based on natural compounds and medicinal plant derivatives, aiming to develop new drugs. This study aimed to investigate the antimicrobial and antibiofilm activities of crude ethanolic extract of O. campechianum (CEE-OC), and commercial (AgNPs-C), non-commercial (AgNPs-NC), and Ocimum campechianum-biosynthesized (AgNPs-OC) silver nanoparticles, against 21 Staphylococcus spp. isolates. Antimicrobial activity of rosmarinic acid (RA) against six isolates was also determined. The minimum inhibitory concentration (MIC) of CEE-OC ranged from 6,250 to 781.25 µg/mL, showing the highest antimicrobial activity among the substances evaluated. AgNPs-OC exhibited MIC values approximately fourfold lower than those of CEE-OC. In contrast, AgNPs-C and AgNPs-NC showed no antimicrobial activity at the concentrations tested. CEE-OC and AgNPs-OC inhibited biofilm formation but had no effect on established biofilms. Molecular docking analysis suggested a potential interaction between RA and the NorA efflux pump protein. The results indicated that O. Campechianum extract and biosynthesized silver nanoparticles may represent promising antimicrobial alternatives, although further studies are needed to elucidate the mechanisms underlying their activity.