Biosynthesis and Characterization of Silver Nanoparticles Produced by Plant Extracts and Its Antimicrobial Activity

Solanum tubersum is the fourth most challenging plant in Egypt, affected by several fungi, viral and bacterial diseases. Bacterial and fungal isolates (Brown rot disease (Ralstonia solaniserum), soft root disease (Pectobacterium carotovora) and dry rot disease (Fusarium oxisporum) were collected. The green extracts of silver nanoparticles were prepared by means of aqueous extracts of three wild plants, Physalis peruviana (leaves, red and green fruits) (N1, N2 and N3), Solanum nigrum (fruit) (N4) and Moringa oliefera (leaves) (N5). SEM, TEM, FT-IR and X-RD obtained the characterization of the biosynthesis of silver nanoparticles. The results indicated that nanoparticles were spherical, smooth and the sizes varied between 12 and 33 nm. The activity of the nanoparticle formulations was tested against the bacterial isolates using agar diffusion method and one fungus using mycelial growth method. The results also elucidated that N5 formulation showed a significantly potent antibacterial activity against R. solanacearum. However, N1 formulation was the highest active one against P. carotovra. In addition, the antifungal activity indicated that N1 had the highest effect (EC50 = 687.03 mg/L) followed by N3 (EC50 = 981.61 mg/L) against F. oxysporium. Nanoparticles synthesized by wild plants could be used as safe alternatives to harmful microbicides.