Assessment of antioxidant, antibacterial and anti-proliferative (lung cancer cell line A549) activities of green synthesized silver nanoparticles from .

In this work, silver nanoparticles (AgNP-DTa) were prepared using an aqueous seed extract of . The importance of the present piece of work is viewed specially with respect to ascertaining the potential of a widely distributed under-utilized mangrove associated plant, (), as medicine. The as-prepared AgNP-DTa were well dispersed and stabilised in aqueous solution through biological ligands extracted from the seeds of . The functional groups present in the bio-ligands of act as reducing and stabilising agents in the formation of nanoparticles. Besides, in the present work, sunlight could induce and catalyse the reduction process of Ag to its corresponding silver atoms of nanoscale dimensions. The size of AgNP-DTa decreased with an increase in the duration of sunlight irradiation. Bio-augmented nanoparticles were characterized by UV-vis spectroscopy, XRD, HR-TEM, DLS, AFM and photoluminescence measurements. Preliminary phytochemical studies and FTIR analysis confirmed the presence of secondary metabolites with hydroxyl, amine and carbonyl groups as reducing/capping agents. AgNP-DTa demonstrated high DPPH scavenging activity with an IC 50 value of 8.25 μg ml. Greater antioxidant activity of AgNP-DTa was also confirmed from total antioxidant capacity (TAC) assay where it was found that the reducing power of 1 g of AgNP-DTa is almost equivalent to that of 1.3 g of Trolox. In addition, highly stable AgNP-DTa showed antibacterial activities against Gram positive and Gram negative bacteria. The as-prepared AgNP-DTa were observed to inhibit the growth of , and and no clear zone was obtained for . With reference to the anti-proliferative activities, AgNP-DTa exhibited moderate activity on A549 lung cancer cell lines with a median effective concentration of 86.23 ± 0.22 μg ml.