Open Access Conference Proceedings

At present, great attention is given to silver nanoparticles (AgNPs), which thanks to its unique properties, such as good electric conductivity, photoelectrochemical activity and antimicrobial activity are widely used. Green synthesis of nanoparticles uses biological molecules from living organisms. Biological extracts may contain molecules which exhibit significant antibacterial, antiviral and cytotoxic effects. The aim of this work was to study the diverse AgNPs synthesized from 10 different types of plant extracts. Extracts from dried plants (0.5 g/25 mL 18 MΩ water) were prepared at 70 ° C by heating for 20 minutes. After filtration, the leachates were mixed in the 1:1 ratio with 0.1 M AgNO3 and allowed to stir at room temperature for 18 hours. They were then mixed in the 1:1 ratio with methanol, shaken for 5 minutes on the rotary mixer, and centrifuged at 12,000 g for 30 minutes. After removing the supernatant, the pellet was dried at 60°C for 24 hours. After weighing, the purified AgNPs were dissolved in 18 MΩ water. AgNPs were yellow, orange and brown. The extraction efficiency was monitored by organic solvents (methanol, ethanol, acetone, propanol). The yields of AgNPs ranged from 15 to 5%, and the most suitable solvent was methanol with an average AgNPs yield of about 10%.AgNPs were characterized spectrally (spectral maxima were in the range of 300-500 nm) by determining the zeta potential and the size of nanoparticles (30-80 nm). Furthermore, antioxidant activity was monitored using ABTS (670 nm), DPPH (517 nm), and FRAP (595 nm) methods. Two methods (ABTS and DPPH) based on the elimination of synthetic radicals and the FRAP method based on the reduction of iron complexes were used to monitor the antioxidant activity. Antioxidation assays were evaluated using calibration curve equations in which the standard was gallic acid. The results for the ABTS and DPPH methods were also expressed as percentage of inhibition of the radicals and in the FRAP method as percentage of reduction activity. The results were calculated using the ABTS method in the range (25.9 - - 84.9%), in the DPPH method (19.2-86.6%) and in the FRAP method (8.5 - 93.2%). Most AgNPs prepared by green synthesis showed significant antioxidant activity.

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