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Recently, nanotechnology has emerged as a tool for the development in the biological synthesis of noble metal nanoparticles. Among other conventional synthesis methods, biological synthesis methods have received great significance due to cost-effective and less hazardous nature which is due to the presence of plentiful as well as diversified biomolecules acting as capping and reducing agents. Biosynthesized silver nanoparticles (Ag NPs) manifest potential applications in several fields because of its safe and environment friendliness. Reported researches on the green synthesis of Ag NPs using different parts of stem, fruits, and seeds has been summarized along with the impact on the morphological properties. This review is important to find a way toward the cheaper, environmentally friendly and controlled synthesis of Ag NPs hence is of special concern. [ABSTRACT FROM AUTHOR]

Different plant extracts have been utilized for biological synthesis of metal nanoparticles. However, no published literature compares the antimicrobial potential of silver nanoparticles (AgNPs) derived from extracts of mature fruit juice (SLF-AgNPs) versus callus (SLC-AgNPs) tissue of same plant. These SLF- and SLC-AgNPs exhibited variable physical and biological properties. Distinct UV-Vis absorption peak (at 250 nm) for SLF-AgNPs indicated formation of small-sized monodisperse particles. Both SLF-AgNPs (5 to 35 nm) and SLC-AgNPs (3 to 270 nm) exhibited quasi-spherical shapes. The FT-IR spectra showed occurrence of shared peaks at 3335, 1647, and 1080 cm−1 while SLC specific peaks at 1065, 1042 and 1017 cm−1. The SLF-AgNPs possessed higher DPPH free radical scavenging potential. These nanoparticles also showed better antibacterial and antimycotic action epitomized as higher inhibition zone diameters compared to SLC-AgNPs. This work can be furthered to identify predominant mechanism for improved antimicrobial potential of the synthesized AgNPs. [ABSTRACT FROM AUTHOR]

The exploitation of various plant materials for the synthesis of nanoparticles is considered as a green technology as it does not necessitate any hazardous chemicals. Here we report the synthesis of silver and gold nanoparticles using an aqueous rhizome extract of a medicinal plant, Costus speciosus by microwave assisted method. The silver and gold nanoparticles show high antimicrobial activities against both bacterial and fungal strains. Also, the nanoparticles exhibit high radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH). Furthermore, the nanoparticles show excellent catalytic activity in the reduction of 4-nitrophenol and methylene blue in the presence of sodium borohydride (NaBH4). [ABSTRACT FROM AUTHOR]