Results
According to Figure 1, the initial sign of silver nanoparticle synthesis
is the changeable of the sample color from light yellow to dark brown.
Figure 2 showed the results of UV-Vis spectroscopy. According to
reference (26), the presence of silver nanoparticles can be inferred
from the absorption peak occurring at a wavelength of 430 nm. This is
because silver tends to absorb light within the range of 400-450 nm.
The X-ray diffraction (XRD) pattern displayed in Figure 3 corresponds to
the synthesis of silver nanoparticles using the hydroalcoholic extract
of the plant. The pattern shows peaks at 2θ values of 23.35°, 27.56°,
32.04°, and 46.00°, which are indicative of the spherical shape of the
nanoparticles. Moreover, the XRD pattern matches perfectly with the
reference pattern (JCPDS No. 04-0783) for silver nanoparticles. The
formula provided can be used to determine the crystallite size of silver
nanoparticles:
\begin{equation}
D=\ \frac{\text{kλ}}{\text{βcosθ}}\nonumber \\
\end{equation}In the above relation, K = 0.9 was the form factor, λ The X-ray
wavelength is equal to 1.5406 angstroms and β is the full width
at half the maximum peak diffraction, θ is the angle corresponding to
the diffraction. From this calculation, the size of silver nanoparticles
was approximately 29 nm (28.46nm ).
To determine the functional groups responsible for the synthesis of
silver nanoparticles in Polygonum aviculare extract, its hydroalcoholic
extract was analyzed using FT-IR spectroscopy. Figure 4 presents the
FT-IR spectrum of this plant extract, where the broad and intense peak
observed at 3416.09 cm-1 represents the stretching vibration of the
hydroxyl group (OH) present in water, phenolic compounds, and
flavonoids. The peak observed at 2926.40 cm-1 corresponds to the
presence of alkyl and CH groups, whereas the peak at 1616.91 cm-1 is
associated with the C=O bond of the amide group and the C=C bond of
aromatic rings. Additionally, the peaks at 1060.81 cm-1 are related to
the presence of ether connections. The FT-IR analysis also revealed the
presence of various functional groups, such as hydroxyl, carboxyl, and
carbonyl, on the surface of the nanoparticles, which contributed to
their negative charge (as shown in Figure 4). The peak at 1604 cm-1 is
attributed to the C=C stretching vibration of aromatic rings, and the
peak at 1360 cm-1 corresponds to C–H bending. The peaks observed at
1061 cm-1 are related to the C-O tensile vibration bonds in the ester
and acid groups, and the bonds at 2839/13 and 2921/88 cm-1 correspond to
the C-H tensile bond in alkane compounds. The strong peaks at 3400 cm-1
correspond to -OH tensile due to the presence of phenolic compounds in
the Polygonum aviculare L. extract. The intensity of most bands is
reduced due to the reduction of silver ions during the synthesis of
silver nanoparticles.
Figure 5 showed the FESEM image of the nanometer dimensions of silver
particles and shows the spherical shape at all magnifications. According
to FESEM images, the cumulative size of nanoparticles varies between 40
and 70 nm .
Figure 6 showed the transmitting electron microscope TEM of silver
nanoparticles synthesized with polygonum aviculare L. extract. As
can be seen from the pictures, silver nanoparticles were in a darker
image and have a spherical shape and a good distribution and around the
nanoparticles, a light background is observed, which is related to the
solvent, and because the density of the solvent against the passage of
light is lower than the density of silver nanoparticles, and therefore
silver nanoparticles are darker and solvent lighter in the image.
Figure 7 and Table 1 showed the Results of the antioxidant properties of
silver nanoparticles. The synthesized showed that the 50% free
radical scavenging (IC50) inhibition rate of the
synthesized nanoparticles was calculated to be
15.63mg
/L Compared to the standard antioxidant ascorbic acid with
IC50 equal to 11.89 mg /L showed excellent antioxidant
activity.
Figure 8 showed that synthesized silver nanoparticles by Polygonum
aviculare L. extract had more antibacterial properties against
Gram-negative E coli. than Gram-positive S. aureus, the highest growth
inhibitory zone corresponds to the concentration of 40 (%v/v) of
synthesized silver nanoparticles and the lowest growth halo corresponds
to the concentration of 10 (%v/v) (Table 2).