Phyto-fabrication, characterization, and biomedical activity of silver nanoparticles mediated from an epiphytic plant Luisia tenuifolia Blume.

The purpose of this study was to assess the ability of an aqueous leaf extract of Luisia tenuifolia to synthesize silver nanoparticles (AgNPs) and their antimicrobial and Aedes aegypti larvicidal activity. The presence of visible color changes ranging from pale yellow to dark brownish confirmed the presence of AgNPs in the reaction mixture. A sharp absorbance peak at 420 nm was found using a UV–visible spectrophotometer, confirming the presence of AgNPs. X-ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR) analyses were used to investigate the crystalline structure and active functional groups involved in the reduction of AgNPs. The synthesized AgNPs were examined using High Resolution Transmission Electron Microscopy (HR-TEM), and it was discovered that the AgNPs were spherical in shape, with sizes ranging from 10 to 30 nm and a diameter of 0.241 nm. The crystalline structure of silver particles (face-centered cubic (fcc)) was confirmed by Selected Area Electron Diffraction (SAED) pattern analysis, which revealed concentric rings and blinking dots. At the highest concentrations (150 µg mL⁻¹), the synthesized AgNPs have significant antimicrobial potential against some common bacterial pathogens such as Salmonella paratyphi (31 mm), Staphylococcus aureus (28 mm), Escherichia coli (20 mm), and Bacillus subtilis (23 mm), as well as phytopathogenic fungi such as Colletotrichum falcatum (12 mm), Fusarium sp. (12 mm), Aspergillus oryzae (10 mm), and Trichoderma sp. (10 mm) at the highest concentration (150 µg mL⁻¹) of AgNPs. Fortunately, the synthesized AgNPs also have significant larvicidal potential against 1^st and 2^nd instar larvae of Ae. aegypti. Thus, aqueous leaf extract of Luisia tenuifolia synthesized AgNPs can be used to benefit humanity. [ABSTRACT FROM AUTHOR]