LAUSR

In India, nanotechnology has been used for therapeutic applications for several millennia. One example of a traditional nanomedicine is Rajath Bhasma, also called calcined silver ash, which has been used for antimicrobial applications and for the treatment of various ailments, such as memory loss, eye diseases, and dehydration. This study aimed to characterize the physical composition and morphology of Rajath Bhasma and its suitability for use as a non-toxic antimicrobial agent. First, Rajath Bhasma was physically characterized via i) Fourier-transform infrared spectroscopy to analyze the surface functional groups, ii) scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy to observe the morphology and elemental composition, and iii) X-ray diffraction to determine the crystalline phases. Thereafter, functional characterization was performed through toxicity screening using zebrafish embryos and through antimicrobial activity assessment against gram-positive (Staphylococcus epidermidis) and gram-negative (Escherichia coli) bacteria. Rajath Bhasma was found to harbor alkene, hydroxyl, aldehyde, and amide functional groups on its surface, which originate from biological components. The main component of Rajath Bhasma is silver, having a particle size of 170-210 nm and existing in the form of spherical aggregates with pure crystalline silver structures. Furthermore, Rajath Bhasma did not exert toxic effects on zebrafish embryos at concentrations below 5 μg/mL and exhibited effective antimicrobial activity against both gram-positive and gram-negative bacteria. The present results indicate that Rajath Bhasma is a potentially effective antimicrobial agent without toxicity when used at a low concentration (5 μg/mL).