Characterization and Evaluation of Antibacterial Activity of Silver Nanoparticles Prepared from Sclerocarya birrea Stem bark and Leaf Extracts

Abstract

The synthesis of silver nanoparticles by using the stem extract and leaf extract of Sclerocarya birrea (Marula) and silver nitrate (AgNO 3) is reported. The synthesized nanoparticles were characterized using ultraviolet-visible spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering, and visual inspection. The antibacterial activity of the synthesized nanoparticles was done by agar disc diffusion method and tested against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The ultraviolet visible absorption spectrum showed broad absorption band at around 430 nm corresponding to that of surface plasmon resonance of silver nanoparticles. The synthesis of silver nanoparticles was also confirmed by color change of AgNO 3 to reddish brown upon addition of Sclerocarya birrea stem and leaf extracts. In addition, change in color of the solution from colorless to brown within 5 min at pH 11 showed that the rate of reduction was faster at this pH compared to lower pH. Transmission electron microscopy analysis proved that the synthesized nanoparticles were spherical in shape; energy-dispersive spectroscopy analysis confirmed the presence of silver in the synthesized nanoparticles; and dynamic light scattering confirmed that the stem nanoparticles were generally larger (36 to 58 nm) than those synthesized from leaf extracts (32 to 48 nm). These nanoparticles were found to possess potential antibacterial activity against E. coli and S. aureus.

Biosynthesis, Characterization, and Biological Activities of Procyanidin Capped Silver Nanoparticles

“…Silver nanoparticles have been in the lead in terms of antibacterial activities [ 72 ]. When various plant parts were used for the synthesis, AgNPs have shown potent bactericidal effects on E. coli and S. aureus [ 72 ]. In the current study, the antibacterial activities of the AgNPs were also studied using wild species of both Gram-positive and Gram-negative bacteria.…”

“…Similarly, nanoparticles (NPs) with similar sizes and MICs have been reported [ 73 ]. Research has shown that the activity of AgNPs is greatly associated with the concentration, shape, and size of the NPs [ 72 , 74 ], and that AgNPs of small sizes at low concentrations are often effective antibacterial agents [ 75 ]. Various researchers evaluated the activity of these NPs with different sizes and shapes against certain species of bacteria [ 74 , 76 , 77 ] and found that 2.5–85 nm-sized AgNPs showed antibacterial activities, while the most effective ones appeared to be between 2.5–20 nm.…”

“…Silver nanoparticles have been in the lead in terms of antibacterial activities [72]. When various plant parts were used for the synthesis, AgNPs have shown potent bactericidal effects on E. coli and S. aureus [72].…”

Antibacterial Activity and Characterization of Chitosan Nanoparticles Prepared from Hijau Lumut Banana ( Musa paradisiaca L.) Peel Ethyl Acetate Extract

“…Herbal medicines optimized by nanotechnology have outstanding advantages over conventional formulations of the active ingredients of plant extracts, including increased solubility and bioavailability, enhanced stability, continuous delivery, increased distribution of tissue macrophages, protection from toxicity, increased pharmacological activity, and protection from physical and chemical degradation [6,7]. Verma et al [8] stated that green nanotechnology in phytoformulations, greatly helps to the environmental sustainability without endangering human health or the environment. In addition, Nyoni et al [9] reported the antibacterial activity of silver nanoparticles prepared from extracts of Sclerocarya birrea leaf and stem bark, which were found to exert antibacterial activity against E. coli and S. aureus.…”