Author(s): R. Meenatchi ammal and G. Vijistella Bai*
The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The present study reports the synthesis of silver (Ag) nanoparticles from silver precursor using the powder of novel Heliotropium indicum. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nanosized Ag particles. The average sizes of the silver nanoparticles were 80 nm to 90 nm as determined through scanning electron microscopy (SEM). Energy-dispersive X-ray spectra (XRD) of silver nanoparticles revealed that the silver was in pure form. The antimicrobial effect of silver nanoparticles were compared with positive control based on inhibition zone in disk diffusion tests microbial sensitivity to nanoparticles was found to vary depending on the microbial species. All the microbial strains depict higher sensitivity to the higher concentration (30 μL) for the test sample when compared to the positive control except B3, B4 and B6. The higher (30 μL/disc) concentration of sample got greater sensitivity than (15 μL/disc) lower concentration in all the tested microorganisms. The anticancer effects of Ag nanoparticles were challenged with HeLa cancerous cells with ten different concentrations (0.6, 1.2, 2.5, 5, 7.5, 10, 15, 20, 25 and 30µg/ml). The Ag nanoparticles inhibited the growth of the cancer cells significantly, in a doseand duration dependent manner.