Green Biosynthesis of Silver Nanoparticles Using Vallarai Chooranam and Their Potential Biomedical Applications

The synthesis of silver nanoparticles was done using vallarai chooranam as a bio reducing agent and ascertained by UV–Visible spectrum at 432 nm. Fourier transform infra-red spectrum revealed that the proteins and other ligands were liable for the capping of synthesized silver nanoparticles (VC-AgNPs). Crystalline nature, spherical shapes particles with the size between 40 to 50 nm and elemental composition were found using X-ray Diffraction, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. By using Dynamic Light Scattering analysis, the average size of silver nanoparticles was found to be 43.1 nm and the zeta potential value was − 47.5 mV implying the stability of VC-AgNPs. The antibacterial activity of VC-AgNPs showed the maximum and minimum zone of inhibition towards E. coli (23 ± 0.69 mm) and Bacillus subtilis (12.67 ± 0.38 mm). The in vitro antioxidant study revealed the free radical scavenging activity of VC-AgNPs by 2,2-diphenyl-1-picrylhydrazyl and Nitric oxide at the inhibitory concentration (IC 50 ) of 23.11 ± 2.05 µg/mL and 36.52 ± 2.37 µg/mL respectively. The anthelmintic efficacy of VC-AgNPs against Pheretima posthumus mortality was found to be 87% at 5 µg/cm 2 . VC-AgNPs showed significant larvicidal activity against Culex quinquefasciatus with a lethal dose of 0.788 ppm and also VC-AgNPs significantly inhibited the production of acetylcholinesterase with the IC 50 value of 0.875 ppm. VC-AgNPs displayed remarkable cytotoxicity against the lung cancer cell line A549 in a dose dependent way with the IC 50 value of 125 µg/mL. We demonstrated that VC-AgNPs can be further exploited as a potential candidate for antibacterial, antioxidant, anthelmintic, larvicidal, anti-acetylcholinesterase and anticancer activity. Graphic Abstract