Green Synthesis of Selenium Nanoparticle Using Leaves Extract of Withania somnifera and Its Biological Applications and Photocatalytic Activities

The green Se NPs (selenium nanoparticles) are formed by simple mixing of Withania somnifera (W. somnifera) leaves extract and selenious acid (H2SeO3) solution. This mixture was stirred which gave a dispersion of Se NPs conjugated with W. somnifera secondary metabolites. The work was focused to determine the phytochemical analysis of leaves extract, green synthesis, its characterization and its applications. Screening analysis showed enormous phytoconstituents in leaves aqueous extract and simultaneously, the synthesized Se NPs by FT-IR spectrum confirm the presence of functional groups which were associated with bioactive molecules. The total flavonoid, phenolic and tannin contents in the aqueous extract were found to be 12.74, 40.54, and 156.33 mu g/mg respectively. The suspension solution confirms the formation of Se NPs showed (310 nm) by UV analysis. X-ray diffraction study exhibits the amorphous nature of Se NPs. Se NPs were spherical in shape within the diameter range of 45-90 nm by FE-SEM. The intense, narrow width of selenium has high purity and was identified using EDX. The TEM analysis exhibited the amorphous nature of particles. Green synthesized Se NPs were found to possess significant antioxidant activity (IC50 -14.81 mu g/mg) and considerable antibacterial activity on Bacillus subtilis (12 mm), Klebsiella pneumoniae (14 mm) and Staphylococcus aureus (19.66 mm). Antiproliferative effects of Se NPs possess great growth control against A549 cells (IC50 at 25 mu g/ml). Se NPs exhibit efficient methylene blue (MB) dye degradation in the presence of sunlight. The present results support the advantages of green method for the production of Se NPs having potential activities. Highlights Withania somnifera leaves extract possesses active phytoconstituents and acts as reducing agents for the preparation of Se NPs and the capping by the phytoconstituents providing stability to Se NPs as evident from FT-IR studies. The green synthesized metal nanoparticle has emerged at low cost, simpler and better choice than physical and chemical methods. Green synthesized Se NPs were found to be almost spherical in shape with particle size around 40-90n m, selenium has high purity and crystalline nature was identified using EDX and XRD. The DPPH scavenging analysis of the amorphous Se NPs has significant antioxidant activity and serves as a potential antibacterial agent to treat diseases caused by bacteria. Antiproliferative activity results suggest that Se NPs possess higher growth control against A549 lung carcinoma cancer cells (IC50 at 25 mu g/ml) which indicated their potential in medical applications. The photocatalytic study concludes that these Se NPs have efficiency to degrade MB under sunlight irradiation. Therefore, they can find application in water treatment plants and textile industries.