Abstract
Plant-mediated synthesis of nanomaterials has been increasingly gaining popularity due to its eco-friendly nature and cost-effectiveness. In the present study, we synthesized silver (Ag) nanoparticles using aqueous extracts of fresh leaves of Impatiens balsamina and Lantana camara medicinal plants as bioreducing agents. This method allowed the synthesis of nanoparticles, which was confirmed by ultraviolet-visible (UV-Vis) spectrophotometry and transmission electron microscopy (TEM). UV-Vis spectra and visual observation showed that the color of the fresh leaf extracts of L. camara and I. balsamina turned into grayish brown and brownish yellow, respectively, after treatment with Ag precursors. In addition, TEM analysis confirmed that AgNO3 solutions for all concentrations produced Ag nanoparticles and their average size was less than 24 nm. Moreover, aqueous leaf extracts of I. balsamina and L. camara were separately tested for their antimicrobial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The results showed that the bacterial growth was inhibited by the extracts containing Ag nanoparticles. Statistical calculation performed using the Tukey test showed that zones of inhibition for the two bacteria produced by the aqueous leaf extracts of L. camara containing 3 mM and 5 mM Ag precursors were not significantly different from that by ciprofloxacin as positive control. On the contrary, there was significant difference between the zone of inhibition for E. coli by ciprofloxacin and that by the extracts of I. balsamina leaves containing 3 mM and 5 mM Ag precursors. A similar result was observed on the zone of inhibition for S. aureus by the extracts of I. balsamina leaves containing 3 mM Ag precursor. It was shown that the aqueous extracts of fresh L. camara leaves containing Ag nanoparticles were comparable to ciprofloxacin in inhibiting bacterial growth.
Highlights
Nanoparticles represent a particle with a nanometer size of 1–100 nm. e nanoscale material has new, unique, and superior physical and chemical properties compared to its bulk structure, due to an increase in the ratio of the surface area per volume of the material/particle [1]. e most widely studied nanoparticle materials are metal nanoparticles because they are easier to synthesize
Color changes are possible because some of the Ag ions begin to be reduced due to the effects of heat and produces Ag+ complex. is complex was responsible for changing color from brownish yellow to grayish brown (L. camara), while the I. balsamina extract remained a brownish yellow (Figure 2 (A2 and B2)). is color change indicates the formation of Ag nanoparticles [25]
E Ag nanoparticles synthesized in each extract solution was analyzed using UV-Vis spectroscopy. is was done to determine the characteristics of the peak spectrum of the Ag nanoparticle wavelength prepared for each different AgNO3 concentrations (1 mM–5 mM) (Figure 3)
Summary
Nanoparticles represent a particle with a nanometer size of 1–100 nm. e nanoscale material has new, unique, and superior physical and chemical properties compared to its bulk structure, due to an increase in the ratio of the surface area per volume of the material/particle [1]. e most widely studied nanoparticle materials are metal nanoparticles because they are easier to synthesize. E most widely studied nanoparticle materials are metal nanoparticles because they are easier to synthesize These materials have a wide range of applications: detectors, catalysts, surface coating agents, and antibacterial/antimicrobials, among many others. E biosynthesis of Ag nanoparticles has been carried out by utilizing a number of plants and evaluating the antimicrobial activity, such as ethanol extracts from Cardiospermum halicacabum L. leaves [18], Impatiens balsamina L. leaves [19], and Lantana camara L. fruits [20]. E present study synthesized Ag nanoparticles using aqueous extracts of fresh leaves of I. balsamina and L. camara and evaluated its antimicrobial activity, against the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria
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