Green Synthesis and Characterization of Silver Nanoparticles using Rhamnus  prinoides (Gesho) Leaf Extract for Antibacterial and Antioxidant Activities

Bekalu Lake

dc.contributor.author	Bekalu Lake
dc.date.accessioned	2023-07-05T08:41:26Z
dc.date.available	2023-07-05T08:41:26Z
dc.date.issued	2023-06
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/15460
dc.description.abstract	In recent years, green synthesis of silver nanoparticles for various applications has gained remarkable attention from researchers due to its advantages than physical and chemical methods of synthesis. In the present study, silver nanoparticles were successfully synthesized from an aqueous extract of Rhamnus prinoides (Gesho) leaf, which was used as a reducing and capping agent. The effects of various reaction conditions, such as concentration of AgNO3, ratio of extract to AgNO3, pH, and incubation time, were optimized. The green synthesized silver nanoparticles were preliminarily confirmed by the visual color change. Furthermore, the synthesized AgNPs were characterized by UV-Visible, FT-IR, XRD, SEM, and TGA techniques. The appearance of a sharp UV-Vis spectra peak at 407 nm confirmed the surface plasmon resonance (SPR) characteristic peak of silver nanoparticles. The FT-IR spectroscopy analysis confirmed the presence of various phytochemicals responsible for reducing silver ions and used as capping agents for synthesized AgNPs. X-ray diffraction (XRD) patterns confirmed the face centered cubic (FCC) structure of AgNPs with an average particle size of 9.45 nm. SEM analysis confirmed the formation of uniformly distributed spherical silver nanoparticles. The TGA result confirmed the existence of phytochemicals which serve as capping agent and the synthesized AgNPs was thermally stable above 500°C. The antibacterial activity of synthesized AgNPs and plant extract was investigated against two gram-negative (E. coli and K. pneumonia) and two gram-positive (S. aureus and S. pyogenes) bacterial species by the disc diffusion method. The results showed that the AgNPs have significant antibacterial activity against all tested bacterial species even at diluted concentration with a maximum ZOI of 14.6±0.57mm compared with the plant extract, with maximum ZOI was found to be 10.6±0.57mm at 100μg/mL. The ciprofloxacin was exhibited maximum ZOI 23±0.57 on S. pyogenes bacteria. Furthermore, the antioxidant activity of synthesized AgNPs and plant extracts was examined using the DPPH assay. The results showed the green synthesized AgNPs had higher antioxidant activity with a lower IC50 value (48.85μg/mL) than the R. prinoides leaf extract with an IC50 of 57.05μg/mL. The IC50 value of ascorbic acid was found to 39.73μg/mL. The present study confirmed that the green synthesized AgNPs using Gesho leaf extract shown significant antibacterial and antioxidant activity for potential applications in medicine, biosensors, water treatment, nanotechnology and other fields. Keywords: AgNPs, Rhamnus prinoides, Green synthesis, antibacterial activity, antioxidant activity	en_US
dc.language.iso	en_US	en_US
dc.subject	Chemistry	en_US
dc.title	Green Synthesis and Characterization of Silver Nanoparticles using Rhamnus prinoides (Gesho) Leaf Extract for Antibacterial and Antioxidant Activities	en_US
dc.type	Thesis	en_US