Structural characterization, antioxidant and in vitro cytotoxic properties of seagrass, Cymodocea serrulata (R.Br.) Asch. & Magnus mediated silver nanoparticles

• Seagrass mediated silver nanoparticles were characterized micrographically.
• FESEM images showed that AgNPs were spherical in shape with a size range of 17–29 nm.
• Dynamic light scattering supported the average size of the CS-AgNPs.
• A single peak in zeta potential signified the presence of repulsion among AgNPs.
• Free radical scavenging and cytotoxicity of CS-AgNPs were assessed.

The present study pertains to the synthesis, structural elucidation, antioxidant and in vitro cytotoxic properties of silver nanoparticles (AgNPs) from marine angiosperm, Cymodocea serrulata aqueous extract (CSAE). The characterization was made through UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), zeta potential and dynamic light scanning (DLS) analyses. The UV–Vis spectrum resulted in a strong surface plasmon resonance (SPR) at 430 nm. The average crystalline size of the AgNPs was predicted through XRD peaks that indicated the 2 theta values of 37.84°, 44.06°, 64.42° and 77.74° for Bragg's refraction index. The functional groups responsible for the bio-reduction of Ag+ into Ag0 were focused through FTIR spectrum. The FESEM images showed that the C. serrulata mediated AgNPs (CS-AgNPs) were spherical in shape. DPPH assay revealed the higher free radical scavenging activity in CS-AgNPs, when compared to CSAE. The cytotoxicity assay on the cervical cancer (HeLa) and African green monkey kidney (Vero) cells upon treatment with CSAE: 107.7 & 124.3 μg ml− 1 and CS-AgNPs: 34.5 & 61.24 μg ml− 1, respectively showed good inhibition rate. These findings highlight the fact that C. serrulata could be a potential source for developing potent drugs and further studies are needed.