Antimicrobial and cytotoxicity properties of biosynthesized gold and silver nanoparticles using D. brittonii aqueous extract

Recently, the production of nanoparticles using biological resources has gained considerable attention due to their application for animal and human well-being. In this study, we used a green synthesis to fabricate gold and silver nanoparticles by reducing HAuCl₄ and AgNO₃ into AuNPs and AgNPs, respectively, using Dudleya brittonii (DB) extract. The physio-chemical properties of the synthesized nanoparticles were analyzed using a UV–vis spectrophotometer, FESEM, EDX, HR-TEM, AFM and FT-IR. Furthermore, the antimicrobial and cytotoxicity activities of DB-AuNPs and DB-AgNPs against livestock pathogenic bacteria and different cell lines, as well as anti-oxidant activity, were investigated. DB synthesized AuNPs and AgNPs were mostly spherical with a few triangular rods and sizes ranging of 5–25 nm and 10–40 nm, respectively. The in vitro antibacterial and antifungal studies demonstrated the DB-AuNPs and DB-AgNPs have good antibacterial activity against E. coli and other livestock pathogens, including Y. pseudotuberculosis and S. typhi. Cell studies revealed that the higher concentrations of both DB-AuNPs and DB-AgNPs (1 µg/ml to 1 mg/ml) showed potent cytotoxicity in chicken cells after 24 hrs, whereas the middle and lower concentrations of DB-AuNPs and DB-AgNPs did not show cytotoxicity in selected cell lines after 24 hrs. In addition, the DB synthesized AuNPs and AgNPs exhibited good free scavenging activity in a dose-dependent manner. Therefore, the biosynthesized nanoparticles can be utilized by the livestock industry to develop an effective source against livestock microbial infections.