Potent bactericidal activity of silver nanoparticles synthesized from Cassia fistula fruit

•Green synthesis of silver nanoparticles (AgNPs) from Cassia fistula fruits.•Size of biogenic AgNPs was ∼69 nm.•Growth kinetics and dose-dependent studies were performed.•Potency: 100% for E. coli and 91% in case of K. pneumoniae.•Minimum inhibitory concentration: E. coli =10 μg mL−1 and K. pneumoniae = 20 μg mL−1.

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.

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