Facile Green Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Origanum majorana with Potential Bioactivity against Multidrug Resistant Bacterial Strains

Abstract

The high prevalence of nosocomial bacterial resistance contributes to significant mortality and morbidity around the world; thus, finding novel antibacterial agents is of vital concern. Accordingly, the present study attempted to synthesize silver nanoparticles (AgNPs) using a green approach. Aqueous leaf extract of Origanum majorana was used to synthesize AgNPs and the antibacterial efficiency against multidrug resistant bacterial strains was detected. Characterization of the biogenic AgNPs was performed using ultraviolet-visible spectrophotometry (UV-Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR) analysis, and X-ray diffraction analysis (XRD). The disc diffusion method was used to detect the antibacterial activity of AgNPs against three nosocomial multidrug-resistant strains. Preliminary UV-Vis analysis revealed the biosynthesis of AgNPs due to peak formation at 374 nm, corresponding to the surface plasmon resonance (SPR) of biogenic AgNPs. TEM micrographs detected the synthesis of small AgNPs with an average particle size of 26.63 nm. EDX analysis revealed the presence of the following elements: oxygen (3.69%), carbon (2.93%), aluminum (1.29), silicon (2.83%), chloride (17.89%), and silver (71.37%). Furthermore, XRD analysis revealed the presence of diffraction peaks at 2 theta (θ) degrees of 38.18°, 44.36°, 64.35°, and 77.54°, assigned to the planes of silver crystals (111), (200), (220), and (311), respectively. Collectively, these findings affirm the synthesis of biogenic AgNPs with potential physicochemical characteristics. The antimicrobial efficiency of the biogenic AgNPs indicated that Klebsiella pneumoniae strain was the most susceptible strain at concentrations of 50 and 100 µg/disk, with inhibitory zones of 21.57 and 24.56 mm, respectively. The minimum inhibitory concentration (MIC) of AgNPs against Klebsiella pneumoniae strain was found to be 10 µg/mL, while the minimum bactericidal concentration (MBC) was found to be 20 µg/mL. In conclusion, aqueous leaf extract of O. majorana mediated synthesis of small sized AgNPs, with potential antimicrobial effectiveness against multidrug-resistant bacterial pathogens.

Bio‐fabrication and characterization of nano‐silver using Kickxia elatine plant and its anti‐diabetic effect on alloxan‐induced Sprague Dawley rats — An in vivo approach

“…KE‐induced AgNPs contain a higher percentage of silver metal (61.67%) than other surface‐coated materials like carbon (15.82%) and oxygen (15.65%). The outcomes of the present studies are in accordance with an earlier report, 99 which suggested that AgNPs synthesized from Origanum majorana extract showed higher percentage of silver. The silver displayed a high intensity peak at 3 keV, confirming the complete conversion of Ag + to AgNPs 100 …”

Preparation of silver nanoparticles by Osbeckia stellata aqueous extract via green synthesis approach: Characterization and assessment of their antioxidant, antidiabetic, cytotoxicity, and antibacterial properties

“…This negative surface charge of Ag NPs showed high stability and electrostatic repulsion 27 . The results were also supported by the previously reported work 11,12,24 …”

“…The peak of extract at 1053 cm −1 and Ag NPs at 1032 cm −1 correspond to –C–O groups of the polyols, showing the presence of the flavones and polysaccharides 12 . The peak at 760 cm −1 for extract and 720 cm −1 for Ag NPs represent C–H bending corresponding to aromatic compound 24 . FTIR spectrum showed a new peak of Ag NPs at 513 cm −1 which was assigned to the –O–H bond between the O‐atom of sliver oxide and hydrogen atom of phenolics at the nanoparticle surface to form Ag NPs 18 .…”

“…The results were also found consistent with previously published works which were specified by the Joint Committee on Powder Diffraction Standards (JCPDS), file No. 04‐0783 5,11,24,26 …”

“…12 The peak at 760 cm −1 for extract and 720 cm −1 for Ag NPs represent C-H bending corresponding to aromatic compound. 24 FTIR spectrum showed a new peak of Ag NPs at 513 cm −1 which was assigned to the -O-H bond between the O-atom of sliver oxide and hydrogen atom of phenolics at the nanoparticle surface to form Ag NPs. 18 The FTIR spectrum analysis supports the effect of functional groups of O. stellata leaves extract as stabilizing and reducing agents for Ag NPs synthesis.…”