Biogenic synthesis, characterization of gold and silver nanoparticles from Coleus forskohlii and their clinical importance

J Photochem Photobiol B. 2018 Jun;183:251-257. doi: 10.1016/j.jphotobiol.2018.04.042. Epub 2018 May 1.


In modern era, the great interest and demand among chemists and researchers for metal nanoparticles is increasing in the application of biomedical fields, textiles, cosmetics and various sectors. Consequently, the present study reports an eco-friendly, cost-effective, rapid and easy method to produce environment-friendly metal nanoparticles to prevent exhaustion of metal resources. In this context, gold and silver metal nanoparticles were green synthesized using the Root Extract of Coleous forskohlii (RECo) as capping and reducing agent. The synthesized gold (GNPs) and silver nanoparticles (SNPs) were characterized using UV-Visible spectrophotometer, High-resolution transmission electron microscopy (HR-TEM), Particle size analysis (PSA), Fourier-transform infrared spectroscopy (FT-IR) and X-Ray Diffractometer (XRD). Their clinical importance was analysed using anti-oxidant assay (DPPH - 2,2-diphenyl-1-picrylhydrazyl and Phosphomolybdenum PMA) and cytotoxicity (MTT assay) against HEPG2 (liver cancer cell lines). Further, the antimicrobial activity against two microorganisms were tested using disc diffusion method against Proteus vulgaris pathogen and Micrococcus luteus pathogen. RECo-GNPs and SNPs were found to be stable in aqueous medium for a longer time and exhibited favorable anti-oxidant, anti-bacterial and anti-cancer activity. The phytoconstituents present in the root extract of Coleous forskohlii was elucidated using GC-MS analysis.

Keywords: Coleus forskohlii; GC–MS; Gold and silver nanoparticles; Green synthesis; Root extract; Therapeutic.

MeSH terms

  • Anti-Infective Agents / chemistry*
  • Anti-Infective Agents / pharmacology
  • Antioxidants / chemistry*
  • Cell Survival / drug effects
  • Disk Diffusion Antimicrobial Tests
  • Gold / chemistry*
  • Green Chemistry Technology
  • Hep G2 Cells
  • Humans
  • Metal Nanoparticles / chemistry*
  • Metal Nanoparticles / toxicity
  • Micrococcus luteus / drug effects
  • Microscopy, Electron, Transmission
  • Plant Extracts / chemistry
  • Plant Roots / chemistry
  • Plant Roots / metabolism
  • Plectranthus / chemistry*
  • Plectranthus / metabolism
  • Proteus vulgaris / drug effects
  • Silver / chemistry*
  • Spectrophotometry, Ultraviolet
  • Spectroscopy, Fourier Transform Infrared
  • X-Ray Diffraction


  • Anti-Infective Agents
  • Antioxidants
  • Plant Extracts
  • Silver
  • Gold