Bio-inspired green synthesis of silver nanoparticles using Acokanthera schimperi and assessment of their anti-bacterial activity against MDR bacteria

Increasing multi drug resistance in bacteria against currently available antibacterial agents, toxicity and allergies are considered as serious health problem. Hence there is an urgent need for the antibacterial agents. This study is the first in its kind which focuses a simple green synthesis of silver nanoparticles (AS-AgNPs) using Acokanthera schimperi aqueous leaf extracts to evaluate in vitro antibacterial activity. The AS-AgNPs were confirmed by using various techniques such as UV-Vis, FTIR, XRD, DLS, TEM, SEM-EDX and evaluation of their antibacterial activity against multidrug-resistant bacteria S. aureus, S. mutans, and K. pneumoniae. TEM analysis revealed that AS-AgNPs are spherical, poly dispersed with an average size of 20.4 nm. XRD analysis displayed that its nature is crystalline. FTIR analysis stated that presence of different functional groups in aqueous leaf extract of A. schimperi act as reducing and capping agents for green synthesis of AS-AgNPs. AS-Ag NPs has shown an enhanced broad spectrum in vitro antibacterial activity against tested S. mutans with zone of inhibition 12.3-17.4 mm, at 50 to 100 µg/mL compared to AS-AQ extract had shown moderate antibacterial activity against S. mutans (9.1-10.7 mm) at 50-100 µg/mL. KEY WORDS: Acokanthera schimperi, Multidrug resistance bacteria, Green synthesis, Silver nanoparticles, Antibacterial activity Bull. Chem. Soc. Ethiop. 2025, 39(10), 2069-2081. DOI: https://dx.doi.org/10.4314/bcse.v39i10.20