Abstract

SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES PRODUCED BY ENDOPHYTIC BACTERIA, ENTEROBACTER LUDWIGII STRAIN GOL9, INHABITING ROOTS OF LEUCAS ASPERA

Dayamrita K. K.* and Nivya Mariam Paul

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Abstract

Endophytes are a novel source of materials and products with great therapeutic potential. The present study reports the green synthesis of silver nanoparticles (AgNPs) from an endophytic bacteria, Enterobacter ludwigii strain Gol9, isolated from the roots of the medicinal plant Leucas aspera. Silver nanoparticles were synthesized and characterized using UV-Vis spectroscopy at around 350 nm. It exhibited significant antimicrobial activity against test organisms including human pathogens. Silver nanoparticles in combination with standard antibiotics exhibited slight synergistic or antagonistic activity against the test organisms. The minimum bactericidal concentration (MBC) shown by silver nanoparticles against Staphylococcus aureus and Klebsiella sp. were 50 μg/μl and 25 μg/μl concentrations respectively. The SEM analysis revealed morphological changes to the test organism, Klebsiella sp. when it was treated with AgNPs. The invitro cytotoxic determination of AgNPs were assessed by MTT assay. It was able to reduce the viability of CHO-K1 cells in a dose dependent manner. This is the first report of the synthesis of silver nanoparticles using an endophytic bacteria Enterobacter ludwigii strain Gol9 from Leucas aspera and its therapeutic potential.

Keywords: endophytes, green synthesis, Leucas aspera, Enterobacter ludwigii, SEM, cytotoxicity.