Evaluation of antibacterial, antioxidant and cytotoxicity potential of silver nanoparticles synthesized from Phlogacanthus thyrsiformis and Centella asiatica

Abstract

The study was focussed around green synthesis of silver nanoparticles using methanol, ethanol and chloroform solvent leaf extract of Phlogacanthus thyrsiformis and Centella asiatica and testing their antioxidant, antibacterial and cytotoxic activities. Silver nanoparticles were synthesized using 1ml of extract sample dissolved in 9 ml of 0.002 M silver nitrate solution and were confirmed by UV–Visible spectrophotometer. The characterization was done by using Field Emission-Scanning Electron Microscope and Fourier Transform Infra-Red spectroscopy. The antioxidant potential, cellular toxicity and bactericidal activity of silver nanoparticles was examined. The results revealed that the synthesized herbal silver nanoparticles were crystalline in nature form, average particle size for P. thyrsiformis was 46 nm whereas 42 nm for C. asiatica and were spherical in shape. The DPPH assay confirmed that the C. asiatica silver nanoparticles have more antioxidant activity as compared to P. thyrsiformis. The synthesized herbal nanoparticles exhibited strong bacteriostatic potential against all the tested bacterial strains. The highest zone of inhibition was recorded against E. coli and B. subtilis in C. asiatica silver nanoparticles at 100 μg/ml concentrations. The strong antioxidant and bactericidal potential of herbal nanoparticles might be contributed to immobilization of bioactive molecules present in plant solvent extracts onto the surface of nanoparticles.