Antimicrobial Activities of Silver Nanoparticles of Capsicum Against Clinical Isolates

ABSTRACT
The emergence of multidrug-resistant pathogens has necessitated the exploration of alternative antimicrobial agents, with silver nanoparticles (AgNPs) gaining significant attention due to their broad-spectrum antimicrobial properties. This study investigated the antimicrobial efficacy of silver nanoparticles synthesized from Capsicum extracts against clinical isolates of Staphylococcus species (Staph sp.), Escherichia coli (E. coli), and Candida albicans (C. albicans). The AgNPs were tested at concentrations of 25, 50, 75, 100, and 125 µg/ml, and their activity was compared to a positive control (AUG). The results demonstrated moderate antimicrobial activity against all tested isolates. For Staph sp., inhibition zones ranged from 14 to 16 mm, with the highest activity observed at 50 µg/ml and 125 µg/ml. Against E. coli, the inhibition zones ranged from 11 to 14 mm, with peak activity at 50 µg/ml. Notably, C. albicans exhibited the highest sensitivity to the AgNPs, with inhibition zones ranging from 9 to 18 mm, and the most significant activity observed at 50 µg/ml (18 mm) and 100 µg/ml (17 mm). However, the positive control (AUG) showed superior activity, with inhibition zones of 23 mm, 30 mm, and 31 mm for Staph sp., E. coli, and C. albicans, respectively. These findings suggest that Capsicum-derived AgNPs possess moderate antimicrobial activity, particularly against C. albicans, but are less effective than standard antibiotics. The lack of a clear dose-dependent trend indicates that factors such as nanoparticle size, shape, and surface properties may play a critical role in their antimicrobial mechanism. This study highlights the potential of Capsicum-derived AgNPs as a complementary antimicrobial agent, particularly for fungal infections, and underscores the need for further optimization and mechanistic studies to enhance their efficacy and applicability in clinical settings.