Anti-bacterial and skin-cancer activity of AuNP, rGO and AuNP-rGO composite using Hemigraphis alternata (Burm.F.) T. Anderson.

Hemigraphis alternata (HA) known as Murikuti, is a traditionally used medicinal plant. Phytochemical screening of leaves shows the presence of bioactive reducing agents. Gold nanoparticles were prepared using aqueous extract of HA leaves at various conventional methods. Concentration variation of gold nanoparticles was studied and optimized under room temperature conditions. Gold nanoparticles (violet colour) were obtained in 5 s. Refluxing method and homogenization method was used to prepare reduced graphene oxide (HAarGO) and nanocomposite (HAaNC) respectively. The prepared metal and non-metallic nanoparticles were characterized by spectroscopic techniques, such as UV–Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Raman spectroscopy, Thermal analysis (TGA/DTG) and Field Emission Scanning Electron Microscopy (FESEM). The average size of the gold nanoparticles is 22.02 nm as of XRD calculations with desired peaks at 38.4° and 44.6° and this attributed to 111 and 222 planes respectively. Gold nanoparticles (Spherical-shape) of size 34.80 nm were seen under FESEM. The synthesized nanoparticles were active against selected Gram-positive and Gram-negative bacteria. Synthesized nanoparticles showed less cell viability (40-20%) on A431 skin cancer cell lines. Apoptotic cell death for HAaNP treated cancer cell lines was noted by Acridine Orange (AO)/Ethidium bromide (EtBr) dual staining and Propidium Iodide (PI) staining method. The findings of this study clearly portray the application of nanoparticles using Hemigraphis alternata as an alternative antibiotic for infectious diseases and skin cancer therapeutics. Image 1 • AuNP, rGO and AuNP-rGO were prepared using H. alternata. • Evaluation of biological activity of Hemigraphis alternata was carried out. • Synthesized nanoparticles suggested for future antibiotics. [ABSTRACT FROM AUTHOR]