Acorus calamus rhizome extract mediated biosynthesis of silver nanoparticles and their bactericidal activity against human pathogens

Abstract

Silver nanoparticle (AgNP) synthesis and characterization is an area of vast interest due to their broader application in the fields of science and technology and medicine. Plants are an attractive source for AgNP synthesis because of its ability to produce a wide range of secondary metabolites with strong reducing potentials. Thus, the present study describes the synthesis of AgNPs using aqueous rhizome extract of Acorus calamus (sweet flag). The AgNP formation was evaluated at different temperatures, incubation time and concentrations of AgNO3 using Response surface methodology based Box–Behnken design (BBD). The synthesized AgNPs were characterized by UV–Visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS). The surface plasmon resonance found at 420 nm confirmed the formation of AgNPs. SEM images reveal that the particles are spherical in nature. The EDS analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. The antibacterial activity of synthesized AgNPs was evaluated against the clinical isolates Staphylococcus aureus and Escherichia coli and it was found that bacterial growth was significantly inhibited in a dose dependent manner. The results suggest that the AgNPs from rhizome extract could be used as a potential antibacterial agent for commercial application.

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“…Strong broad O-H stretch carboxylic bands in the region 1564cm -1 and carboxylic stretching bands in the regions 1645cm -1 were observed 3 . These bands denote stretching vibrational bands responsible for efficient capping and stabilization of silver nanoparticles.…”

“…The bactericidal activity of the biosynthesized Acorus calamus rhizome silver nanoparticles showed maximum zone of inhibition against Staphylococcus aureus (1.5 cm) and minimum zone of inhibition against Salmonella enterica 0.8 cm 3 . AgNPs exhibit antibacterial activity by attaching to the sulphur containing proteins of the cell membrane, thereby causing membrne damage and depleting the levels of intracellular ATP of the microorganism.…”

“…The results are in conformity with Dinesh et al, 2012 14 , who reported color change after 30 minutes of incubation. A rhizome extract of Acorous calamus were reported to reduce silver ions into silver nanoparticles after 48 hours 3 . The dissimilarities in the rate of bioreduction observed may be due to the differences in the activities of the enzyme present in the plant extracts 16 .…”

A review on plant mediated synthesis of silver nanoparticles and their antimicrobial activity against various pathogenic bacteria

“…63 The color change in Ag nano solution is attribute to the surface plasmon resonance, where free electrons give rise to a surface plasmon resonance (SPR) absorption band. 4,7,25,42,46,47,58,64 The XRD has used for the analysis of both molecular and crystal structures. It also can be used for qualitative identification of various compounds, quantitative resolution of chemical species and for measuring the degree of crystallinity.…”

“…The Green method has the feasibility to easily scaled up for large scale syntheses of NPs. 4,6,7,8,9 This review article is focused mainly on the study of plant extract mediated synthesis of silver NPs, the antimicrobial activity of Ag NPs exhibited against various pathogenic bacteria and summarize the publications based on the studies conducted around the globe.…”