Anticancer, antimicrobial and photocatalytic activities of green synthesized magnesium oxide nanoparticles (MgONPs) using aqueous extract of Sargassum wightii.

A rapid and ecofriendly fabrication of metal oxide nanoparticles using biogenic sources is the current trend being used to replace the toxic chemical method. The present study was carried out to synthesize magnesium oxide nanoparticles (MgONPs) using the marine brown algae Sargassum wighitii as the reducing and capping agent. The as-prepared MgONPs were characterized by spectroscopic and microscopic analyses. UV-visible spectrum of the MgONPs showed a sharp absorption peak at 322 nm. X- ray diffraction analysis illustrated that the MgONPs were crystalline in nature with a face-centered cubic structure. Presence of magnesium and oxygen were further confirmed by EDX profile. FTIR analysis showed the presence of functional groups specific for sulfated polysaccharides, which might be responsible for the synthesis of MgONPs. Zeta potential and dynamic light scattering analysis illustrated that the MgONPs were highly stable at 19.8 mV with an average size of 68.06 nm. MgONPs showed potent antibacterial activity and antifungal activities against human pathogens. Photocatalytic activity of MgONPs was witnessed by the quick degradation of the organic dye methylene blue on exposure to both sunlight and UV irradiation. MgONPs showed significant cytotoxicity against the lung cancer cell lines A549 in a dose dependent manner with the IC₅₀ value of 37.5 ± 0.34 μg/ml. Safety evaluation using peripheral blood mononuclear cells (PBMCs) illustrated the MgONPs to be non-toxic in nature. Overall, the results concluded that the MgONPs generated using marine algae have exhibited scope for multifaceted biological applications.