Non-antibacterial as well as non-anticancer activity of flower extract and its biogenous silver nanoparticles

Silver nanoparticles were synthesized by using the white flower extract of Albizia lebbeck as a source of reducing and capping agents. A. lebbeck white flower extract and silver nanoparticles were checked for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa and Ba cillus subtilis by using Mueller Hinton agar, nutrient agar and Luria Bertani agar using the well diffusion method. The synthesized silver nanoparticles did not show antibacterial activity at lower (0.1-0.4 mg ml^-1) or higher (0.5-2.5 mg ml^-1) concentrations against any of the four organisms on either of the media, even though silver nanoparticles have been well known to show antibacterial activity even at lower concentrations. The non-antibacterial properties of the synthesized silver nanoparticles against all four bacteria were confirmed using viability counting. With this unique non-antibacterial property of biogenous silver nanoparticles observed in this study, it can be stated that case by case evaluation of every synthesized silver nanoparticle needs to be done as there are multiple factors influencing their properties. Anticancer activity of these nanoparticles at different concentrations against A549 cancer cells did not show any significant decrease in cell viability highlighting its biocompatible nature. Thus, these silver nanoparticles can be a best suited candidate for drug delivery.