Preparation of monodispersed and cytotoxic silver nanoparticles using Launaea taraxacifolia leaf extract

The current work investigated the green and low-cost preparation of silver nanoparticles (AgNPs) using the aqueous extract from Launaea taraxacifolia leaf and studied its antimicrobial effects. The leaf extract was analysed in a gas chromatogram–mass spectrometer to assess the phytochemicals present. UV–Vis spectrophotometer was used to monitor the formation of AgNPs, the morphological assessment was performed by a scanning electron microscope, energy dispersive X-ray analysis was used to determine the elemental composition, the particle size and shape were studied using transmission electron microscopy, and the vibrational modes of bonds in the AgNPs were assessed by Fourier transformed infrared spectroscopy. The AgNPs produced were spherical and in a size range of 9–15.5 nm, monodispersed with a large surface area. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the AgNPs against Pseudomonas aeruginosa and Proteus mirabilis were very low. Against P. aeruginosa, the MIC was 0.10 mg/mL and the MBC was 0.15 mg/mL, while the MIC and MBC against P. mirabilis were 0.05 and 0.25 mg/mL, respectively. Therefore, the AgNPs prepared using L. taraxacifolia leaf extract showed high antibacterial activities and could be a candidate antimicrobial agent for biomedical applications.