Аннотация:The present study reports phytogenic synthesis of nanoparticles using aqueous extract of Rhizophora mangle. The synthesized nanopartides were characterized using UV-Visible spectroscopy with maximum absorption at 400 nm. Fourier Transform Infrared spectroscopy (FT-IR) studies revealed the presence of functional groups mediating the synthesis of nanoparticles. X-ray diffraction (XRD) displayed Bragg's intensities at 2θ angle which confirmed the crystalline nature of the nanoparticles. Transmission Electron Microscopy (ТЕМ) revealed size and shape of the nanopartides with polydispersity of nanoparticles and size of 10-60 nm. The synthesized nanoparticles expressed antibacterial activity by well diffusion assay, broth micro dilution assay, minimal inhibitory concentration and CFU assay against selective human pathogens. Nanoparticles were more effective against S. aureus (MTCC7443) followed by B. subtilis (MTCC 121). E. coli (MTCC 7410) and S. typhi (MTCC 7407). The possible mode of action of nanopartides was studied by treating silver nanopartides with pathogenic DNA which showed defamed and damage DNA in comparison with control DNA.