Nanotherapeutics has emerged as the most sought after
approach
to tackle the menace of drug-resistant pathogenic bacteria. Among
others, biogenic silver nanoparticles (bAgNPs) synthesized using medicinal
plant extracts demonstrate promising antibacterial propensity with
excellent biocompatibility. Herein, bAgNPs were synthesized through
the green chemistry approach using
Syzygium cymosum
leaf extract as a reducing agent at different pH values (i.e., 5,
7, 8, and 10). The average size of bAgNPs synthesized at pH 5, 7,
8, and 10 was 23.3, 21.3, 17.2, and 35.3 nm, respectively, and all
the nanoparticles were negatively charged. Their antibacterial potential
was investigated against
Bacillus subtilis
,
Escherichia coli
DH5α,
E. coli
K12, enteropathogenic
E. coli
, and
Salmonella typhi
. The highest
antibacterial activity was exhibited by bAgNPs synthesized at pH 8
against all the tested bacterial strains, which can be attributed
to their small size and greater surface area to volume ratio. The
bAgNPs demonstrated the highest zone of inhibition (29.5 ± 0.8
mm) against
B. subtilis
through oxidation
of membrane fatty acids that resulted in the formation of the malondialdehyde–thiobarbituric
acid (MDA–TBA) adduct. However, bAgNPs demonstrated excellent
hemocompatibility with rat and human red blood cells. Biogenic AgNPs
synthesized at pH 8 also exhibited biocompatibility in terms of liver
and kidney function biomarkers. Furthermore, hematoxylin and eosin
staining of the tissue sections of vital organs (i.e., liver, kidneys,
lungs, heart, spleen, and brain) also confirmed the biocompatibility
of bAgNPs.