Paper Title
Plant-Mediated Synthesis of Nanoparticles
Abstract
Nanoparticles have a wide range of unconventional properties due to their large surface area-to-volume ratio and
quantum confinement which makes them suitable for applications in medicine. However, the synthesis of nanoparticles using
chemical methods is unsuitable for medical applications due to the use of toxic chemicals therefore focus has shifted to
bio-based methods of synthesis that are non-toxic. In this study, we capitalise on the combined and synergistic effects of
nanoparticles and secondary metabolites from indigenous medicinal plants found in South Africa through plant-mediated
synthesis of nanoparticles. Silver nanoparticles were synthesised using sodium borohydride, crude plant extracts from
Harpephyllum caffrum (an indigenous South African medicinal plant) and (+)-catechin (isolated from H. caffrum). Formation
of silver nanoparticles was confirmed by the surface plasmon resonance band at 419.2 nm in the UV-Vis spectrum. The
morphology and sizes of the silver nanoparticles was determined using transmission electron microscopy (TEM). The
antioxidant activity of crude extracts, (+)-catechin and synthesised nanoparticles were determined using the DPPH assay. The
end-capped nanoparticles and (+)-catechin showed higher scavenging activity even at low concentrations relative to the
standard, ascorbic acid.
Keywords - Nanoparticles, flavonoid, catechin, Harpephyllum caffrum