Green synthesis, characterization and biological activity analysis of silver nanoparticles from commercially available root powder of Picrorhiza kurroa Royle ex Benth.

Picrorhiza kurroa Royle ex Benth., a medicinal plant native to the alpine regions of the Himalayas, is renowned for its diverse therapeutic properties. Recently, green-synthesized silver nanoparticles have gained attention for their potential in pharmaceutical and industrial applications. In this study, silver nanoparticles (Pk-AgNPs) were synthesized using commercially available root powder of P. kurroa. The objective was to evaluate their potential biomedical applications by assessing their antioxidant properties and cytotoxicity. The Pk-AgNPs were characterized using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR), which revealed their morphology and functional groups. The Total Antioxidant Capacity (TAC) of methanolic root extract of P. kurroa (PkRE) and the Pk-AgNPs was determined using the Phosphomolybdenum method. The results indicated that the antioxidant activity of PkRE was higher than that of the Pk-AgNPs. Moreover, the activity increased with concentration, ranging from 20 µg/mL to 120 µg/mL, demonstrating their capability to eliminate harmful free radicals. The cytotoxicity of PkRE and Pk-AgNPs was evaluated using the MTT assay against the SV40 T-antigen-containing HEK293T cell line, derived from human embryonic kidney 293 cells and the L929 cell line, a mouse fibroblast cell line. The results demonstrated dose-dependent cytotoxicity. L929 cells remained 100 % viable at concentration up to 200 µg/mL for PkRE and 100 µg/mL Pk-AgNPs. In contrast, HEK293T cells didn’t show 100 % viability even at a concentration of 50 µg/mL for both samples. This study highlights the potential use of PkRE and Pk-AgNPs as antioxidants. However, the cytotoxicity findings suggests that they may be harmful to humans if consumed orally, though they could be suitable for use in other organisms. This paves the way for further research into the application of AgNPs synthesized from P. kurroa in biomedical and pharmaceutical domains as well as in veterinary sciences.