Synthesis, Characterization and studies on antibacterial activity of colloidal silver nanoparticles from Artocarpus hirsutus fruit extract

Abstract

The present work reports the synthesis, characterization and antibacterial properties of colloidal silver nanoparticles using the fruit extract of Artocarpus hirsutus commonly known as wild jack. It is a tropical evergreen tree species that is native to Kerala and Karnataka, India. The Artocarpus hirsutus fruit extract was mixed with aqueous AgNO3 solution under constant agitation at room temperature for 9 to 12hrs. The reduction of silver ions by phytochemicals present in the fruit extract leads to the formation of stable colloidal Artocarpushirsutus silver nanoparticles (AHAg NPs). Characterization of AHAgNPs was carried out by UV Vis spectrum, FTIR, XRD, DLS and TEM. The peak obtained at 430nm using UV-VIS spectroscopy confirmed the formation of silver nanoparticles. The results of DLS indicated that the average size of AHAg NPs obtained from Artocorpushirsutus fruit extract was 100 nm. The FTIR spectra of AHAg NPs, where the peaks were obtained at 3305 cm-1, 2930 cm-1, 2158 cm-1, 1648 cm-1, 1393 cm-1, 1149 cm-1, 1015 cm-1, corresponded to OH group of alcohols or phenols, C-H of alkanes, CC group of alkynes, C=C group of alkenes, C=O, C-N group of aliphatic amine, C-O group of alcohols, carboxylic acids, esters or ethers. These peaks depict stretching vibrations responsible for polyphenols such as flavonoids, terpenoids and fatty acids and also proteins XRD analysis confirmed the homogeneous crystalline nature of the AHAg NPs with size of about 32 nm. Transmission electron microscopy analysis showed the spherical morphology of silver nanoparticles with particle size 20 nm. DLS analysis was also done to measure the particle size and its distribution. The silver nanoparticles demonstrated potent antibacterial activity against Streptococcus pneumoniae, Salmonella typhi, Pseudomonas aeruginosa etc.