Momordica charantia stem extract mediated biogenic synthesis of silver nanoparticles: optical and antimicrobial efficacy

In this study, potential of aqueous stem extract of Momordica charantia for phytosynthesis of silver nanoparticles (Ag NPs) was evaluated using reduction method. The locally sourced biodiversity was extracted in water and methanol by cold extraction, after which it was screened for the presence of phytochemicals. Optical measurement was carried out with Uv-visible spectrophotometer, evidence of capping and reduction of Ag+ to Ag° by the biomolecules in the plant extract was achieved using Fourier transformed infra-red (FT-IR). Antimicrobial activity of the green synthesized nanoparticles was tested on clinical isolates. Visual evidence of Ag NPs formation was detected by change in reaction solution colour from light brown to deep brown, which resulted in excitation of surface plasmon resonance (SPR) between 400- 450 nm. Growths of microbes used were significantly inhibited (P < 0.05) with increasing concentrations of Ag NPS. Moderate activity was displayed by Ag NPs with the same value of MIC and MBC (12.5 mg/mL) on all the organisms considered except P. aeruginosa in which low activity was observed. The enhanced SPR displayed by Ag NPs qualifies them as potential materials for therapeutic and diagnostic uses