Green Synthesis and Antimicrobial Potency of Silver Nanoparticles from Ocimum gratissimum Leaf Extract on Clinical Isolates of Escherichia coli and Klebsiella Pneumoniae Isolated from Patients in a Tertiary Health Hospital, Abakaliki, Ebonyi State, Nigeria.

Abstract

Background: Nanoparticles are gaining importance in research especially in the field of medicine. This study was aimed at synthesizing silver nanoparticles (AgNPs) from Ocimum gratissimum and determining their therapeutic potentials against clinical isolates of E. coli and K. pneumoniae.

Methods: AgNPs was synthesized by mixing aqueous leaf extract of O. gratissimum and 1 mM of AgNO3 at the ratio of 1:4, heated on a sand bath at 60oC for 30min and observed for colour change. The formation of AgNPs was further confirmed by studying the optical properties of the solution using a UV visible spectroscope. Antibacterial assays of the synthesized AgNPs against clinical isolates of E. coli and K. pneumoniae was assessed using agar well diffusion techniques.

Results: Aqueous leaf extract of O. gratissimum was able to synthesize AgNPs as colour changed from dark orange to dark brown. Both the ethanoic leaf extract of O. gratissimum and AgNPs showed high antibacterial activities against the isolates. However, the synthesized AgNPs using O. gratissimum leaves extract showed higher activity than the ethanoic leaf extract only. The result of the two different concentrations of AgNPs against E. coli showed that at 100μg/ml and 150μg/ml, an IZD of 20 and 21 (mm) was observed. While in K. pneumoniae isolates, an IZD of 18 and 20 (mm) was observed at 100μg/ml and 150μg/ml concentrations.

Conclusion: In-vivo and in-vitro studies to establish the most effective, efficient and safety doses for the treatment of diseases using O. gratissimum is therefore recommended.