After the change of solution color, absorption spectral analysis was done by pipetting about 1 ml of the AgNPs solution into UV quartz cuvette cell and monitored in 6715 UV/Vis spectrophotometer in room temperature at the wavelength between 300 and 600 nm at a resolution of 1 nm and deionized water as a blank.

Nanoparticles morphology was observed by scanning electron microscopy. The analysis was carried out after centrifugation of AgNPs solution at 4000 rpm for 30 min. The filtrate was discarded and the pellet was dried at 45˚C in the oven to avoid any changes in the shape of nanoparticles. After drying, a small portion of the dried pellet was placed on carbon conductive tape for preparation to examine the morphology and elemental analysis using Scanning Electron Microscope (JEOL, JSM7600F).

The characterization of functional groups on the surface AgNPs of A. ampeloprasum extract before and after the reduction of AgNO₃ were investigated. The solution was centrifuged at 7800 rpm for 30 min, the filtrate was discarded and the pellet was re-dispersed with sterilized distilled water. The centrifugation and re-dispersion was repeated three times to ensure the purification of nanoparticles. After the last centrifugation, the filtrate was discarded and the pellet was placed in freeze drying system (LABCONCO FreeZone 4.5) until dried up completely. A small portion of the dried powdered samples was placed in the sample area of FTIR spectroscopy (IRAffinity-1, Shimadzu, Japan) and the spectra was scanned in the range of 500 - 4000 cm⁻¹ at a resolution of 20 cm⁻¹ in transmittance mode.

AgNPs solution and A. ampeloprasum extract were tested against five fungal isolates (A. flavus (ATCC 16875), A. flavus (ATCC 11498), A. ochraceus (ATCC 22947), A. parasiticus (ATCC 15517) and A. niger (ATCC 16404). These fungal strains were purchased from Cairo Microbiological Resources Centre, Faculty of Agriculture, Ain Shams University. 100 µl of the tested solutions were added in wells of 6 mm diameters in PDA plates which were inoculated previously by spreading a freshly prepared fungal inoculum by using sterile cotton swabs over the entire agar surface and left for 60 min at laboratory temperature. The plates were left for 60 minutes at laboratory temperature to allow proper diffusion of each extract to the medium. The plates were further incubated at 25˚C for 5 to 7 days. The experiment was performed in triplicates [19] [20].

The Minimum inhibitory concentration of AgNPs solution was carried out using Broth microdilution method against all fungal isolates [21]. The microtiter plates were incubated at 28˚C for 5 - 7 days in the shaking incubator. The MIC results determined by changing in optical density of the broth or by using an ELISA reader. Presence of clear PD broth with no density indicates the MIC.

Small agar pieces were cut out from the inhibition zone after 7 days’ incubation periods, fixed for 3 hours in 2.5% (v/v) glutaraldehyde (100 mM) phosphate buffer solution (pH 7.2) and then fixed in 1% (w/v) osmium tetroxide (O_SO₄) for an hour. The agar blocks were dehydrated in a graded series of methanol and methanol: isoamylacetate (C₇H₁₄O₂). The specimens were dried with a critical point drier using liquid Carbon dioxide (CO₂) and coated with gold-coater for 5 minutes. The coated samples were observed under JSM-5600 LV with accelerating voltage of 10 kV [22].

The results of ultraviolet-visible light spectroscopy analysis showed the maximum absorption peak that occurred at the wavelength of 437 nm which refers to silver nanoparticles formation from A. ampeloprasum extract as shown in “Figure 2”. This wavelength raised due to the surface Plasmon resonance of the particles. The A. ampeloprasum AgNPs UV absorption peak was similar to AgNPs UV absorption peak 437 nm obtained by Erythrina indica root [27] and agreed with the uv-vis results of AgNPsA. Ampeloprasum prepared from aqueous leaf extract [28]. The results agreed with the statement of Sastry et al., (1997) that AgNPs exhibit a maximum UV-visible absorption in the range of 400 - 500 nm because of surface plasmon resonance [29].

Scanning electron microscope (SEM) analysis was used in this work to observe the size and morphology of nanoparticles by electron charge oscillation principle in silver nanoparticles that exhibit by light [30]. The results of SEM analysis in “Figure 3” show that silver nanoparticles were found to be spherical in shape and were aggregated. This is in concordance with SEM analysis results of synthesized AgNPs using fruit extract of Momordica cymbalaria [31] , Lippia nodiflora leave extract AgNPs [32] and Plectranthus zeylanicus leaf extract AgNPs [33]. This aggregation in silver nanoparticles may be due to secondary metabolites that are present in the leaf extracts [34].

Fourier transform infrared (FTIR) spectroscopy was used to evaluate chemical bonds in surface atoms and functional atoms on the surface of AgNPs [35] [36]. The capability of plant extracts to reduce AgNO₃ to AgNPs is due to the presence of secondary metabolites which play the main role in changing electron charge and convert it to nano-sized particles [37]. As shown in “Figure 4” the FTIR analysis of A. ampeloprasum extract before and after the addition of silver

nitrates, showing a decrease in some absorption peaks after the reaction at the wavelengths 3600 - 4000 cm⁻¹. It is also noticed that many absorption peaks disappeared after the addition of silver nitrates at wavelengths from 2000 to 3400 cm⁻¹. The decrease of some absorption peaks, as well as the displacement or reduction of others after the addition of silver nitrates to the plant extract is due to the interaction of reduction of nitrates group with some other extract groups

from carboxylic acids and the Amine group and all lead to the formation of nitric acid and silver nanoparticles formation.

Generally, FTIR results suggested that stabilization of the AgNPs may have resulted from binding of the carbonyl group of the reducing sugars to the silver [38]. Proteins may bind to AgNPs through free amine groups or carboxyl groups of amino acid residue in it. IR spectroscopic study confirmed that the plant extract can perform dual functions of reduction and stabilization of AgNPs [39]. Similar results were observed in previous study of Ricinus communis leaf extract produced AgNPs [40] and A. ampeloprasum aqueous leaf extract AgNPs [28].

Based on these FTIR studies, clearly reveals hydroxyl groups of phenols and amide groups of proteins from plant extract forming a layer to the nanoparticles and acting as a capping agent to prevent agglomeration and providing stability in the medium. Phenolic compounds belonging to the lignans group have been earlier reported to be capable of chelating with metallic elements to form complexes [41]. Thus, it can be concluded that hydroxyl and carboxyl groups present in phenolic compounds play a key role. These results confirm the presence of phenols and proteins which may act as reducing and stabilizing agents for silver nanoparticles and agreed with Najda et al. (2015) results of secondary metabolites and antioxidant in A. ampeloprasum [42].