Discussion and conclusion
The synthesis of nanomaterials is at present one of the most active
fields in the field of nanosciences. One of the nanomaterials is silver
nanoparticles, which have known inhibitory and antibacterial effects.
Silver ions can bind to electron donor groups such as glucose, oxygen,
or nitrogen in a biological molecule (22). Silver nanoparticles break
down the inhibitory components in the outer membrane of the bacterium,
releasing molecularly exponential molecules such as the liposuction
molecule. After penetrating the bacterial cell, nanosilver inactivates
its enzymes and causes the death of the bacterium by producing hydrogen
peroxide (23). Various techniques exist for synthesizing nanoparticles,
but physical and chemical methods can cause environmental pollution. To
mitigate this issue, green methods can be employed, where materials with
minimal environmental impact are either produced or consumed as an
alternative (24). Furthermore, research has demonstrated that the
presence of silver ions can significantly enhance the generation of
reactive oxygen species, such as superoxide anion radicals, which can
induce oxidative stress at the molecular, cellular, and organ levels
(25). Plants have antimicrobial and antioxidant activity due to the
presence of secondary metabolites such as phenol and flavonoids which
act to prevent oxidative damage to cells. Certain plants can convert
Ag+ ions to Ag0, synthesizing
nanoparticles with antioxidant properties through a process called
bioremediation (26). It has antimicrobial and antioxidant activity and
acts to prevent oxidative damage to cells. Researchers have increasingly
viewed the synthesis of nanoparticles by plants and microorganisms as a
biocompatible and environmentally friendly approach in recent years. The
study examined the abilities of the nanoparticles that were created to
act as antioxidants and antibacterials. During the study, a change in
color was observed from light yellow to dark brown, which was caused by
the interaction between the plant extract and silver salt solution. This
color change was consistent with the findings of Rezazadeh et al. (27),
Givianrad et al. (28), and Dousti et al. (29), and it served as the
initial indication of the production of silver nanoparticles. Dousti et
al. conducted Uv-Vis spectroscopy on the silver nanoparticles they
synthesized and found that the maximum absorption occurred around 430
nm. The presence of a peak in this region is an indication of silver
nanoparticle synthesis because such a peak, occurs at a wavelength of
400 - 450 nm, this phenomenon is caused by the induction of free
electrons within the nanoparticles. The surface plasmon resonance
observed in silver nanoparticles is linked to the induction of unbound
electrons within the nanoparticles. This effect is responsible for the
phenomenon. This outcome aligns with the discoveries made by Dousti et
al. and other researchers (29). Also, Dousti et al. synthesized silver
nanoparticles from the blue extract of the Fumaria Parviflora plant, and
their XRD analysis showed peaks at 38.07°, 44.26°, 64.43°, and 77.35°
with indices (311), (220), (200), and (111), respectively. These peaks
correspond to the nanostructures of the silver particles and are in
complete agreement with the XRD pattern of silver. The size of the
silver nanoparticles’ crystallinity was determined using Debye
Scherrer’s formula, which yielded a size of 30 nm for the nanoparticles.
as well as the X-ray diffraction (XRD) pattern obtained from the
nanoparticles created using Polygonum aviculare L. indicated that the
characteristic peaks at 2θ values of 23.35°, 27.56°, 32.04°, and 46.00°,
which are attributed to the spherical shape of silver nanoparticles and
agreed with the XRD reference pattern of silver nanoparticles (JCPDS No.
04-0783). as well as, the size of the silver was determined to be 29nm
using Debye-Scherrer’s equation, which agreed with the findings of
Dousti et al.’s study (23, 30, 8, 29). Heydarzadeh and colleagues
conducted a study on the eco-friendly production of silver nanoparticles
using Citrus aurantium extract. The transmission electron microscope
(TEM) images revealed that the silver nanoparticles had a spherical
shape and appeared darker in the images. The nanoparticles obtained had
a diameter ranging from 5 to 40 nm. FESEM images of silver nanoparticles
synthesized with orange spring extract with different magnifications
also showed the nanometer dimensions of the silver particles and
indicated an almost spherical shape in all magnifications. According to
the FESEM images, the cumulative size of the nanoparticles was between
10 - 60 nm . also, in this study, the FESEM image of the nanometer
dimensions of silver particles shows the spherical shape at all
magnifications. According to FESEM images, the cumulative size of
nanoparticles varies between 40 and 70 nm , and the TEM image of
silver nanoparticles synthesized from polygonum aviculare L. extract
showed the silver nanoparticles were in a darker image and had a
spherical shape and a size of less than 50 nm which It was in
good agreement with the results of Heydarzadeh and his colleagues (40).
Since it is important to find both natural and synthetic antioxidants to
prevent oxidative stress and its harmful effects, the study also aimed
to examine the antioxidant properties of the produced nanoparticles. The
study showed that the synthesized nanoparticles were able to remove
radicals the free 2 and 2-diphenyl-1-picryl is hydrazyl in such a way
that by receiving an electron or free radical, hydrogen is converted
into a stable molecule. Polygonum aviculare plant can transfer hydrogen
to oxidants and antioxidant properties so the results showed that the
antioxidant properties of synthesized nanoparticles depend on their
concentration and with increasing concentration, antioxidant activity
increases. The silver nanoparticles exhibited remarkable antioxidant
activity, with an IC50 value of 15.63 mg/l , when
compared to the standard antioxidant ascorbic acid, which had an
IC50 value of 11.89 mg/l . This discovery aligns
with the outcomes observed in earlier investigations (31). Abdolaziz and
colleagues (32) conducted a study on the antioxidant activity of silver
nanoparticles synthesized from the leaf extract of the Salmak plant
using the DPPH test. The results revealed that the antioxidant effect
was directly proportional to the concentration of silver nanoparticles,
with an increase in concentration up to 20 mg/l resulting in a
measurement of 63.45 ± 0.18 mg/l . Our research findings indicated
that the inhibitory ability of nanoparticles produced using the
hydroalcoholic extract of Polygonum aviculare L. plant was 41.01 at a
concentration of 10 mg/l, and it increased to 93.13 at concentrations up
to 100 mg/l, with statistical significance at p <0.05. This
result is in line with previous studies (33, 34) and demonstrates a
notable variation. When used at a concentration of 40% (%v/v) against
S. aureus and E. coli, the average diameter of the growth inhibition
zone was 10 mm and 12 mm, respectively. The research established that
silver nanoparticles produced via the green method were more highly
efficient in inhibiting the growth of gram-negative bacteria, like E.
coli than gram-positive bacteria, such as
S. aureus. This observation is
consistent with the findings of Mobarak Ali et al. (36) and (35), who
suggest that the thicker cell wall of gram-positive bacteria, such as S.
aureus is the reason for this result. In contrast, gram-negative
bacteria have a thinner cell wall, and their outer surface is covered by
a layer of lipopolysaccharide. Due to the weak positive charge of silver
nanoparticles, their interaction with bacteria is facilitated by the
negative charge present on the surface of these microorganisms. This
interaction is thought to result in the creation of a hole in the cell
wall, which can ultimately lead to the entry of nanoparticles into the
bacterial cell and the bacterium’s subsequent death. Also Vastava et al.
(37) and Guzman et al. (38) reported in their milk studies that the
antibacterial effectiveness of nanoparticles increases as their size
decreases. Therefore, the difference in the minimum inhibitory
concentration and the minimum bactericidal concentration in the
synthesized nanoparticles Can also be attributed to the difference in
size. This difference in the results can also be related to the type of
nanoparticle shape as well as the structural and genetic differences of
the strains according to the geographical location. Silver nanoparticles
from common drugs can be a suitable alternative for them. The method
utilized in this investigation to synthesize silver nanoparticles from
the P. aviculare L. extract is regarded as an advantageous approach
eco-friendly. Cost-effectiveness, avoidance of toxic solvents, waste and
antimicrobial activity, and other biomedical applications allow this
method to be used in large commercial comparisons.