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An investigation of the optimal conditions for the green synthesis of silver nanoparticles using an aqueous extract from the plant Agrimonia eupatoria L.
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1  University of Kragujevac, Institute for Information Technologies, Jovana Cvijica bb, 34000 Kragujevac, Serbia
Academic Editor: José Luis Arias Mediano


In green synthesis, nanoparticles are synthesized using inexpensive and environmentally friendly synthesis technologies. Organism extracts can be used both as reducing agents and as stabilizers in the synthesis of nanoparticles. Silver nanoparticles have characteristic physical, chemical, and biological properties. Their catalytic activity and antibacterial activity are very significant, but also excellent for the possibility of application in nanobiotechnological research.

In this research, we used silver nitrate and an aqueous extract of the plant Agrimonia eupatoria L. for the synthesis of silver nanoparticles (AgNPs). Agrimonia eupatoria L. (common name: agrimony) belongs to the family Rosaceae (Tribe: Sanguisorbeae). The plant is known for being used as a raw material for the extraction of medicinal ingredients or the production of medicines in the pharmaceutical industry. The plant has antioxidant and antibacterial properties, but also anti-inflammatory, neuroprotective, antidiabetic, hepatoprotective, and anticancer properties.

The optimal conditions for this green synthesis were examined: the concentration of starting substances, pH value, and temperature. Silver nitrate was dissolved in concentrations of 5 mM, 10 mM, and 20 mM. The pH of the reaction mixtures was adjusted to 4, 6, and 8 using solutions of 0.1 M NaOH and 0.1 M HNO3. The reaction mixture was heated to 25°C and 50°C on a magnetic stirrer under controlled conditions. Visual color change (from light yellow to dark brown) and UV-Vis s spectrophotometry were used to monitor the process of AgNPs formation.

Spectra of formed nanoparticles (200–800 nm) were recorded, and the highest peaks were found between 425–500 nm, suggesting AgNPs were formed. The best conditions for the most increased AgNPs yield production were а 5 mM concentration of AgNO3, 1% concentration of extract, reaction temperature of 25 °C, pH=6, and a reaction time of 3 h for synthesis.

Keywords: Silver Nanoparticles, Green Synthesis, Agrimonia eupatoria L.