Green synthesis, characterization, and antioxidant activity of silver nanoparticles using Stachys annua L. subsp. annua var. annua

Nanoparticles (NPs) are known as fundamental building blocks of nanotechnology. In this work, silver nanoparticles (AgNPs) were synthesized using Stachys annua L. sabsp. annua var. annua. The structure of AgNPs was elucidated by FTIR, UV-Vis, XRD, SEM analyses. The UV-Vis spectrum revealed the maximum absorption at 469 nm and SEM spectral analysis showed the formation of spherical shape AgNPs with an average size of 75.21 nm. XRD analysis at 2 theta degrees of 38.1 degrees, 44.3 degrees, 64.4 degrees, and 77.4 degrees can be assigned to the (111), (200), (220) and (311) face-centered cubic crystalline structure. Antioxidant activity of extract and AgNPs was executed using the DPPH center dot scavenging, ABTS(center dot+) scavenging, and reducing power assays. AgNPs and extract revealed the higher DPPH center dot free radical scavenging effect with the values of 10.2 +/- 0.34 (lC(50), mu g/mL) and 9.26 +/- 0.37 (lC(50), mu g/mL) than the standard BHT (11.13 +/- 0.10, lC(50), mu g/mL). ABTS(center dot+) activity of AgNPs (4.11 +/- 0.04, lC(50), mu g/mL) and extract (3.96 +/- 0.10) were found higher than that of the standard BHT. In reducing power assay, the activity of AgNPs (2.61 +/- 0.02, mu mol TE/mg extract) and extract (3.05 +/- 0.15, mu mol TE/mg extract) was lower than BHT. Hence, extract and AgNPs could be promising materials for antioxidant agents.