Metallic nanoparticles are being utilized in every phase of science along with engineering including medical fields and are still charming the scientists to explore new dimensions for their respective worth which is generally attributed to their corresponding small sizes. The up-and-coming researches have proven their antimicrobial significance. Among several noble metal nanoparticles, silver nanoparticles have attained a special focus. Conventionally silver nanoparticles are synthesized by chemical method using chemicals as reducing agents which later on become accountable for various biological risks due to their general toxicity; engendering the serious concern to develop environment friendly processes. Thus, to solve the objective; biological approaches are coming up to fill the void; for instance green syntheses using biological molecules derived from plant sources in the form of extracts exhibiting superiority over chemical and/or biological methods. These plant based biological molecules undergo highly controlled assembly for making them suitable for the metal nanoparticle syntheses. The present review explores the huge plant diversity to be utilized towards rapid and single step protocol preparatory method with green principles over the conventional ones and describes the antimicrobial activities of silver nanoparticles.

In this study, rapid, simple approach was applied for synthesis of silver nanoparticles using Azadirachta indica aqueous leaf extract. The plant extract acts both as reducing agent as well as capping agent. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by FTIR. Various techniques used to characterize synthesized nanoparticles are DLS, photoluminescence, TEM and UV–Visible spectrophotometer. UV–Visible spectrophotometer showed absorbance peak in range of 436–446 nm. The silver nanoparticles showed antibacterial activities against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) microorganisms. Photoluminescence studies of synthesised silver nanoparticles were also evaluated. Results confirmed this protocol as simple, rapid, one step, eco-friendly, non-toxic and an alternative conventional physical/chemical methods. Only 15 min were required for the conversion of silver ions into silver nanoparticles at room temperature, without the involvement of any hazardous chemical