Antioxidant and cytotoxic effect of biologically synthesized selenium nanoparticles in comparison to selenium dioxide.

The present study was designed to evaluate antioxidant and cytotoxic effect of selenium nanoparticles (Se NPs) biosynthesized by a newly isolated marine bacterial strain Bacillus sp. MSh-1. An organic–aqueous partitioning system was applied for purification of the biogenic Se NPs and the purified Se NPs were then investigated for antioxidant activity using DPPH scavenging activity and reducing power assay. Cytotoxic effect of the biogenic Se NPs and selenium dioxide (SeO₂) on MCF-7 cell line was assesed by MTT assay. Tranmission electron micrograph (TEM) of the purified Se NPs showed individual and spherical nanostructure in size range of about 80–220nm. The obtained results showed that, at the same concentration of 200μg/mL, Se NPs and SeO₂ represented scavenging activity of 23.1±3.4% and 13.2±3.1%, respectively. However, the data obtained from reducing power assay revealed higher electron-donating activity of SeO₂ compared to Se NPs. Higher IC₅₀ of the Se NPs (41.5±0.9μg/mL) compared to SeO₂ (6.7±0.8μg/mL) confirmed lower cytotoxicity of the biogenic Se NPs on MCF-7 cell line. [ABSTRACT FROM AUTHOR]