Preprint / Version 1

Characterization of Rajath Bhasma and Evaluation of Its Toxicity in Zebrafish Embryos and Its Antimicrobial Activity

Authors

  • Kalishwaralal Kalimuthu Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Ji Kim Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Chandramohan Subburaman Department of Biotechnology, Kalasalingam University, Krishnankoil, India
  • Woo Kwon Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Sung Hwang Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Sehan Jeong Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Min Jo Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Hyung Kim Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
  • Ki Park Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea

Keywords:

Rajath Bhasma, silver, characterization, embryo toxicity, antimicrobial activity

Abstract

In India, nanotechnology has been used in therapeutic applications for several millennia. One example of a traditional nanomedicine is Rajath Bhasma (also called calcined silver ash), which is used as an antimicrobial and for the treatment of various ailments and conditions such as memory loss, eye diseases, and dehydration. In this study, we 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 energydispersive 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 originating from biological components on its surface. The main component of Rajath Bhasma is silver, with 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 concentrations below 5 μg/ml. Keywords: Rajath Bhasma, silver, characterization, embryo toxicity, antimicrobial activity

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