Synthesis, Characteristation and Biological Activity of Silver Nanoparticles Generated
Using the Leaf and Stembark Extract of Combretum erythrophyllum
Authors: Bantho Sahejna , Naidoo Yougasphree , Dewir Yaser H. , Singh Moganavelli , Lin Johnson , Bantho Ayuvna 
Published: April 2023

Background:
Medicinal plants are known to contain numerous phytometabolites with suggested pharmacological value. Literature suggests that the medicinal use of phytometabolites in its natural state has limited success due
to poor absorption rates. Currently, the focus lies on synthesizing phytometabolites extracted from medicinal plants and
silver ions to generate nano-scale carriers with specialized properties. Thus, the nano-synthesis of phytometabolites
with silver (Ag+) ions is proposed. The use of silver is promoted due to its known antibacterial and antioxidant effectiveness, among many. Nanotechnology allows for the green generation of nano-scaled particles that are able to penetrate target areas due to its size and unique structure. Therefore, this study aimed to generate a novel protocol for the
synthesis of AgNP’s using the leaf and stembark extracts of C. erythrophyllum. In addition, the biological activity of
the generated nanoparticles was evaluated.

Objectives:
To synthesis silver nanoparticles (AgNP’s) using the leaf and stembark extracts of Combretum erythrophyllum. The relative shape, size, distribution, and zeta potential of the synthesised particles were characterized using
transmission electron microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX),
Nanoparticle tracking analysis (NTA), and UV Spectrophotometry (UV -vis). To screen the synthesised particles for its
potential antibacterial, apoptotic and cytotoxic properties

Methods:
A novel protocol for the synthesis of silver nanoparticles (AgNP’s) using the leaf and stembark extracts of
Combretum erythrophyllum was established. The generated AgNP’s were characterised using transmission electron
microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), Nanoparticle tracking
analysis (NTA), and UV Spectrophotometry (UV -vis). Furthermore, the AgNP’s were evaluated for their antibacterial,
cytotoxic and apoptotic activity against a range of bacterial strains and cancer cells. Characterisation was based upon
particle size, shape and elemental silver composition

Results:
Within the stembark extract, synthesised nanoparticles were large, spherical in shape and dense in elemental
silver composition. While synthesised nanoparticles of the leaf extract were small to medium in size, varied in shape
established and contained minimal quantities of silver (substantiated by the TEM and NTA results). Furthermore, it
was established that the synthesized nanoparticles exhibited high antibacterial properties due to the conducted antibacterial assay. The FTIR analysis revealed the presence of numerous functional groups within active compounds found in
the synthesised extracts. Functional groups found varied between the leaf and stembark extracts, each with proposed
pharmacological activity.

Conclusion:
Presently, antibiotic-resistant bacteria are continuously evolving thus, posing as a threat to conventional
drug delivery systems. Nanotechnology provides a platform that enables the formulation of a low-toxicity and hypersensitive drug delivery system. Further studies evaluating the biological activity of extracts of C. erythrophyllum synthesized with silver nanoparticles could enhance its proposed pharmaceutical value