Utilization of marine seaweed Spyridia filamentosa for silver nanoparticles synthesis and its clinical applications

•Silver nanoparticles (AgNPs) were successfully synthesized from the marine seaweed Spyridia filamentosa.•The adopted synthesis method was eco-friendly, and rapid.•The AgNPs are well dispersed and spherical in shape 20–30 nm in size.•AgNPs showed extensive antibacterial activity against both Gram-positive and Gram-negative bacteria.•AgNPs exhibited potential cytotoxic activity against MCF-7 cells. The present study describes an environment-friendly biosynthesis of silver nanoparticles from marine red algae Spyridia filamentosa through the bio-reduction process. S. filamentosa have significantly high amounts of phytochemicals and secondary metabolites responsible for the formation of AgNPs. UV–Vis spectra results showed corresponding AgNPs peak at 420 nm. Transmission electron micrographs showed well dispersed spherical particles with the 20–30 nm in size. FT-IR and XRD results revealed the characteristics of AgNPs. Further, the AgNPs displayed potential antibacterial activity against Staphylococcus sp. (KC688883) and Klebsiella sp.(KC899845), and anticancer activity against MCF-7 cells.