Investigation of antibacterial activity of silver nanoparticles synthesized from Scrophularia striata fruit extract

Aim: In this research, a simple and rapid method (green synthesis) was applied for synthesis of silver nanoparticles (AgNPs) using Scrophularia striata fruit extract, so that the metabolites present in S.striata fruit extract caused to reduce silver ions to AgNPs in green synthesis process.
Material and UV–visible spectroscopy and scanning electron microscopy (SEM) were used to characterize the synthesized nanoparticles from S. striata extract. The antibacterial activity of the synthesized silver nanoparticles from S. striata extract was investigated against Gram-negative bacteria (Escherichia coli clinical, Escherichia coli ATCC, Salmonella typhi ATCC and Klebsiella pneumoniae) and Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using microdilution technique. The antibacterial activity was determined by agar well diffusion method.
The results showed that with increased concentration of silver nanoparticles, antibacterial activity increased and in the concentration of 5 mM silver nanoparticles, antibacterial activity was observed against all bacteria, however the highest antibacterial activity of silver nanoparticles observed against Staphylococcus aureus (inhibition zone diameter with 32 mm). Also, in the low concentrations of 0.312 and 0.625 mM of silver nanoparticles, no inhibitory effects were observed on the Klebsiella pneumoniae and Salmonella typhi ATCC.
From the results, it is suggested that silver nanoparticles synthesized using S. striata fruit extract could be used as a suitable antibacterial agent against clinical pathogens.