Screening of Antibacterial, Anti-Biofilm, Cell Proliferation Inhibition, and Synergistic Effects of Biogenic Synthesized Silver Nanostructures Using Trillium govanianum with Antibiotics
Authors: Nazia Gulzar Nazia Gulzar , Saiqa Andleeb Saiqa Andleeb , Shaukat Ali Shaukat Ali , Sadia Nazer Sadia Nazer , Tariq Iqbal Muhammad Abdul Rauf Khan and Abida Raza Tariq Iqbal Muhammad Abdul Rauf Khan and Abida Raza 
Published: December 2021

The aim of study is to develop the economic plant-based antibacterial agents to improve the treatment strategies for bacterial infections at nano-scale. In current research silver nanostructures synthesis was carried out using Trillium govanianum aqueous extract. Characterizations were done using UV–Visible spectrophotometer, scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Antibacterial efficacy of green-synthesized silver nanostructures and aqueous extract was evaluated via agar well diffusion method, crystal violet assay (antibiofilm analysis), tetrazolium salt assay (cell viability assay), Direct agar overlay technique, and TLC- spot screening against clinical bacterial pathogens. Synergistic effect of synthesized nanostructures, aqueous extract along with antibiotics was determined by agar disc diffusion method. Minimum inhibitory concentration was also evaluated using agar well diffusion method. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) method was used for screening of antioxidant potential effect at various concentrations (0.5, 1 and 1.5 and#181;l). The indication of major phytochemical constituents was determined using both qualitative methods and Thin Layer Chromatography (TLC). Absorbance in UV region (295 nm) corresponds to the out of plane quadrupole Plasmon-resonance while at 350 nm corresponds to in-plane dipole resonance. SEM images shows prepared the morphology of Ag nanostructures TGAgNSs is not exactly spherical while XRD analysis shows that highly crystalline TGAgNSs have been prepared with average crystallite size of 27.94 nm. The FTIR spectrum represents sharp peaks of aldehyde, amide I, aromatic rings, and polysaccharides. Minimum inhibitory concentration showed the increased bactericidal effect with increase in concentration of silver nanostructures. Maximum inhibition of E. coli, S. epidermidis, S. pyogenes, and K. pneumonia was recorded at 0.12 mg/ml concentration of TGAgNSs with 7.6.0and#177;0.0 mm, 7.6and#177;0.0 mm, 6.6and#177;0.0 mm, and 7.0and#177;0.0 mm zones of inhibition. Similarly, TGAgNSs showed maximum inhibition of E. coli, S. pyogenes, and S. marcesscens at 0.14 mg/ml concentration (8.3and#177;0.0 mm, 7.0and#177;0.0 mm, 7.0and#177;0.0 mm), respectively. Cell viability, antibiofilm assay, TLC-spot screening, and TLC-bio-autography proves the potential antibacterial effect of TGAgNSs. Synergistic effect showed greater antibacterial effect. Glycosides, saponins, flavonoids, proteins, terpenoids, alkaloids, phenols, and tannins were detected. The scavenging potential of TGAgNSs was calculated as 74% at 1.5 and#181;l. It was concluded that green synthesized nanostructures have efficient antibacterial potential and would be used in medical devices to cure infections in near future.