Potent bactericidal activity of silver nanoparticles synthesized from Cassia fistula fruit

We demonstrated one-step synthesis of silver nanoparticles (AgNPs) from Cassia fistula fruit extract and their antibacterial activity against E. coli and K. pneumoniae. Biogenic AgNPs were characterized by scanning electron microscopy, X-Ray diffraction and fourier transform infrared spectroscopy. Results confirmed spherical shaped AgNPs with an average crystallite size of ∼69 nm. Dose-dependent (0, 10, 20, 40 and 80 μg mL⁻¹) growth kinetic studies showed 100% potency against E. coli (20 μg mL⁻¹) and K. pneumoniae (80 μg mL⁻¹) after 1 and 5 h, respectively. Surface morphology analysis revealed formation of groove/pits in the lysed cell membrane that eventually led to bacterial death.