Nanostructured gold in ancient Ayurvedic calcined drug 'swarnabhasma'

Swarnabhasma (calcined gold) is a famous ancient Ayurvedic medicine. However, its detail characteristic investigations are very limited.

Herein, investigation of swarnabhasma is demonstrated using ancient and ultramodern techniques to understand the physicochemical nature of this drug, and to understand whether the mercury [Parada] used during preparation method marks its presence in swarnabhasma.

The investigated swarnabhasma was prepared by repeated incinerations of Au-Hg-Lemon juice amalgamation and sulphur. The bhasma was tested by all traditional tests of rasashastra. It was characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Field Emission Transmission Electron Microscopy (FE-TEM), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Energy Dispersive X-ray Fluorescence (EDXRF), Fourier Transform Infrared Spectroscopy (FTIR), and gravimetric analysis.

Traditional tests of rasashastra were complied by the sample. XRD confirms that swarnabhasma consists of principally pure gold at nanoscale. FE-SEM showed agglomerated particles. FE-TEM showed that swarnabhasma contains highly crystalline nanostructured gold comprised with spherical gold nanoparticles of size, 5-20 nm. ICP-AES exhibited absolute absence of Hg and presence of Au, Si, Ag, Al, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr, Ti, and Zn. EDXRF confirmed the absence of mercury and confirmed the presence of Au, Si, Zr, Nb, S, Cl, K, Ca, Fe, and Ni. FTIR confirmed presence of water molecules adsorbed over surface of bhasma. Gravimetric analysis confirmed presence of 95% gold.

Nano-structuring of gold enhances the surface area as well as activity. The present investigation shows that the entire process from rasashastra confers the unique nanostructure to gold and same is responsible for its medicinal potential. This nanomedicine is highly stable, which is specified as niruttha and apunarbhava in rasashastra.