Green synthesis of silver nanoparticles using piper betle leaf extract and their antimicrobial properties against isolated phyto-pathogen model

Abstract

Silver nanoparticles are well known as one of the promising agent especially for antibacterial activity. This project was aimed to evaluate the synthesized silver nanoparticles from Piper betle and their antimicrobial properties against phyto-pathogen model. The formation of silver nanoparticles in aqueous extract were confirmed by colour changes from yellowish to brown. To further confirm the presence of silver nanoparticles, UV-Vis spectrum was used and the absorbance of the silver nanoparticles were analysed at 452 nm. Antimicrobial activity of the synthesized silver nanoparticles of P. bettle was evaluated by using agar well plate on Escherichia coli (gram-negative bacteria), Pseudomonas aeruginasa (gram-positive bacteria) and the Aspergillus niger (fungi). The results show that synthesized silver nanoparticles on 1 mM concentration exhibits admirable zone of inhibition against E. coli, P. aeruginasa and A. niger (14.1±0.13, 14.5±0.17 and 14.7±0.40 mm, respectively). All the synthesized silver nanoparticles show significant antimicrobial activity compared to the aqueous extract of P. bettle. Minimum inhibition concentration (MIC) of the best synthesized silver nanoparticles of P. bettle (1 Mm) was further evaluated and shows that P. aeruginasa, E. coli and A. niger was perceived at three-fold, two-fold and one-fold dilution from the original samples respectively. In order to characterize the size and shape of silver nanoparticles, field emission scanning electron microscope (FESEM) was used and revealed that silver nanoparticles were in spherical shape that range from 15 to 19 nm in size. The presence of elemental silver was obtained by using energy-dispersive spectroscopy (EDX), which suggests that silver is presence as the primary element at absorption range 2.8 keV.