Chemical and physical stability, high adsorption
capacity and low-toxicological profile are very
important features for application of nanoparticles
(NPs) in the biomedical field. Physicochemical and
biochemical characteristics of nanoparticles are very
much dependent on the synthesis method. One of the
promising, environmentally conscious method is the
green synthesis of NPs using plant extracts. The aim
of the this research was to present new plant extract
for the synthesis of zinc oxide nanoparticles (ZnO
NPs) and to test antimicrobial activity of in this way
obtained ZnO NPs.
In this study acetonic extract of flowers of
Geranium robertianum L. (Geraniaceae) was used
for phytosynthesis of zinc oxide nanoparticles (ZnO
NPs). G. robertianum aerial parts are a good source of
plant phenolics, particularly flavonoids which have an
important role in metal nanoparticle synthesis. Total
flavonoid content (4.2%) of acetonic extract used
in ZnO NPs synthesis was determined by aluminum
chloride spectrophotometric assay on 425 nm.
Characterization of ZnO nanoparticles obtained by
phytosynthesis procedure was done using UV/VIS
spectrophotometry and IC spectroscopy. Obtained
ZnO NPs were also tested as potential antimicrobial
agents, considering that microorganisms rarely
develop antimicrobial resistance against NPs. The
Muller-Hinton agar well diffusion method was used
for evaluation of ZnO NPs antimicrobial activity
against Gram negative (Escherichia coli, Acinetobacter
baumannii, and Pseudomonas aeruginosa) and Gram
positive (three clinical isolates of Staphylococcus
aureus) bacteria.
The total flavonoid content of acetonic extract
of flowers of G. robertianum used for ZnO NPs
synthesis was 4.2%. The size of obtained ZnO NPs
was approximately 40 nm. All three S. aureus isolates
exhibited sensitivity (average value of inhibition zones
around 15 mm), while Gram-negative bacteria were
resistant to ZnO NPs activity.
The results from our study confirm that acetonic
extract of flowers of G. robertianum can be used for
synthesis of ZnO NPs with significant antimicrobial
activity towards Gram-positive bacteria.
