Green synthesis and antibacterial activities of silver nanoparticles against Escherichia coli, Salmonella typhi, Pseudomonas aeruginosaand Staphylococcus aureus

Abstract

Background: Over the last two decades infectious agents have become more dangerous, most especially in developing countries, due to their ability to develop resistance against orthodox medicines. Many in these countries are suffering from the debilitating effects of these pathogens without any remedies in sight. The recent researches in nanoparticles derived from medicinal plants seem to be yielding positive results. Methods: We carried out synthesis of silver nanoparticles from AgNO3 and using Hyaluronic acid as a stabilizing agent to avoid aggregation in green synthesis from Ziziphus spinachristi and Garcinia kola. Transmission electron microscopy (TEM) was used to determine particle size and shape. Disc diffusion technique was used to study the susceptibility patterns of the particles on the test organisms- Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Staphylococcus aureus. Result: The nanoparticles exhibited very high activity against the pathogens at very low concentration and showed remarkable higher activity than the crude extracts and standard antibiotics (control) with very wide zones of inhibition. The zones of inhibition ranged from 12.4±0.11 – 15.1±0.22 for the nanoparticles as against, 8.7±0.21 – 9.2±0.32 for the crude and 10.7±0.22 – 12.7±0.88 for the standard antibiotics. Conclusion: Green synthesis of silver nanoparticles may give the long awaited breakthrough against these infectious agents to ameliorate, if not completely, win the war against these pathogens.

Keywords

• Green synthesis
• Silver nanoparticles
• Ziziphus spinachristi
• Garcinia kola
• Antimicrobial activities