The present study is focused on the evaluation of bioeffects of silver nanoparticles (AgNPs) synthesized by Bacillus subtilis strain I’-1a, the producer of iturin A lipopeptide biosurfactant. The following properties of biologically synthesized silver nanoparticles (bio-AgNPs) were evaluated: in vitro cytotoxicity, antioxidant properties, and metabolic activities of mammalian cells. As a control, chemically synthesized silver nanoparticles (chem-AgNPs) were used. In vitro, antioxidant activity of bio-AgNPs showed a significant effect on the scavenging of free radicals. Bio-AgNPs can be potent natural antioxidants and can be essential for health preservation against oxidative stress-related degenerative diseases, such as cancer. The cell viability of human skin fibroblasts NHDF was remarkably inhibited in the presence of both AgNPs. However, bio-AgNPs were more active than chem-AgNPs. In our experiment, microarrays PM-M1–PM-M4 were used to evaluate the growth of NHDF fibroblast cells in the presence of bio-AgNPs and chem-AgNPs. The NHDF fibroblast cells were more active in the presence of bio-AgNPs than in chem-AgNPs. Probably, the presence of biosurfactant produced by Bacillus subtilis I’-1a significantly increased the stability of biogenic AgNPs and enhanced their biological activities and specific interaction with human DNA. Furthermore, the evaluated biological activities were enhanced for the biosurfactant-based AgNPs.

This study illustrates the antifungal activity of green biosynthesis of a silver nanoparticle solution using one of Sinai’s natural plant extracts, namely Zygophyllum album which was used as a stabilizer and reducing agent to reduce Ag+ to metallic silver. In this study the plant extract was prepared by boiling in water for 10 min., 70% ethanol and wet autoclaving for 5 min. AgNPs were prepared using these three different extract methods. Transmission electron microscope (TEM) and zeta potential techniques were employed to characterize the synthesis of nanoparticles. The size of particles ranged from 6.28 nm to 28.89 nm at x100 and the zeta potential had one peak at –16.6 mean (mV) at area 100% for green synthesized AgNPs from Z. album prepared from boiling in water for 10 min. The size of particles ranged from 6.64 nm to 54.82nm at 100x and the zeta potential had one peak at – 12.9 mean (mV) at 100% area for green synthesized AgNPs from the plant ethanol extract. The size of particles ranged from 9.39 nm to 31.93 nm at 100x and the zeta potential had one peak – 19.8 mean (mV) at 100% area for green synthesized AgNPs from the wet autoclaved plant extract of Z. album for 5 min. All treatments of plant extract and AgNPs solutions, prepared from these plant extracts of Zygophyllum album, were compared with the positive control and Tachigaren – 30% W/P was conducted on the radial growth of F. oxysporium and caused antifungal activity with a high inhibition percent. There was a highly significant difference between the various extraction techniques. Increasing the concentration of treatments was accompanied with a significant effect on Fusarium wilt. Thus, this study may provide a good alternative approach to control Fusarium wilt disease in the field and under storage conditions of vegetables. Our study suggests that silver nanoparticles of plant extracts can be used for controlling Fusarium wilt.