Introduction: The use of antimicrobial compounds in plants and nanoparticles for control and treatment of disease agents have been extensively studied. The present study aimed to biosynthesis of silver nanoparticles using leaf aqueous extract of Sambucus ebulus L. and study of their antimicrobial activity.

Materials & methods: To biosynthesis of silver nanoparticles, fresh extract was prepared and added to silver nitrate solution with concentration 1 mM. Effective parameters on synthesis of silver nanoparticles such as; pH, the volume of extract, silver ion concentration, temperature and reaction time were optimized and studied to obtain individual shape and size of nanoparticles. Antimicrobial activities of extract and silver nanoparticles were studied with the Disc diffusion and MIC methods against four bacterias such as; Staphylococcus aureus (PTTC 1112), Bacillus cereus (PTTC 1154), Escherichia coli (PTTC 1399), Pseudomonas aeruginosa (PTTC 1707) and two Fungus such as; Aspergillus niger (PTTC 5012) and Candida albicans (PTTC 5027).

Findings:  After adding the extract to the silver nitrate solution, the color changed to brown that represents to successful synthesis of silver nanoparticles. Silver nanoparticles showed maximum absorbance at 405 nm and they were spherical shape and the average size of them had been between 8-12 nm. These nanoparticles showed significant antimicrobial activity on samples, so that they were prevented the growth of bacterias and fungus in very low concentration.

Discussion & conclusions: Because of existing the antioxidant properties and many secondary compounds in plant, they have a role in reducing and stabilizing the nanoparticles. In this study, the silver nanoparticles synthesized by leaf aqueous extracts of S. ebulus. The silver nanoparticles showed high antimicrobial activity.