ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Biogenic synthesis, antioxidant and antimicrobial activity of silver and manganese dioxide nanoparticles using Cussonia zuluensis Strey

Nomfundo T. Mahlangeni, Judie Magura, Roshila Moodley, Himansu Baijnath, and Hafizah Chenia

School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa

E-mail: moodleyrosh@ukzn.ac.za

Received: 24 January 2020  Accepted: 4 June 2020

Abstract:

Synthesis of nanoparticles using naturally occurring biomolecules has become the preferred method due to increased concerns over environmental degradation. In this study, the biosynthesis of manganese dioxide nanoparticles (MnO₂NPs) and silver nanoparticles (AgNPs) using extracts and the biomolecule, aralia cerebroside, isolated from the medicinal plant species, Cussonia zuluensis Strey, was investigated. The size and morphology of nanoparticles observed using microscopic techniques indicated an average particle size of 7.43 nm (spherical and polydispersed) for AgNPs and a layer of thin film surrounding the particles, confirming the capping by biomolecules. AgNPs exhibited better antibacterial activity than MnO₂NPs and were most active against Escherichia coli and Enterococcus faecalis. MnO₂NPs presented as ultrathin nanoflakes with grainy morphology ranging from 11 to 29 nm when capped with biomolecules from the extract, and presented as nanospheres surrounded by nanosheets ranging from 6.99 to 16.57 nm when capped with aralia cerebroside. The radical scavenging activity was found to be MnO₂NPs (extract) > MnO₂NPs (cerebroside) > AgNPs (extract) > extract > cerebroside, and the ferric reducing antioxidant power was found to be cerebroside > extract > MnO₂NPs (cerebroside) > MnO₂NPs (extract) > AgNPs (extract). MnO₂NPs exhibited better antioxidant activity than AgNPs with size and morphology of nanoparticles being influenced by the capping agent, which, in turn, influenced antioxidant activity as seen with MnO₂NPs. This study confirms the significance of the metal or metal oxide core and capping biomolecules for targeted therapeutic activity of nanoparticles using the plant-mediated synthesis route.

Keywords: Aralia cerebroside; Silver nanoparticles; Radical scavenging activity; Escherichia coli; Enterococcus faecalis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01244-9

Chemical Papers 74 (12) 4253–4265 (2020)