Biogenesis of Au Nanoparticles from Plant-Derived Metabolites – <i>In Vitro</i> and <i>In Vivo</i> Studies

Biomimetic gold nanoparticles (Au NPs) were synthesized via a sustainable approach without any additional toxic chemical reagents and fully characterized. It was proven that only whole aqueous extracts of <i>Rosa damascene</i> (RD) and <i>Rosa rugosa</i> (RR) are powerful enough to reduce, graft, and stabilize metallic nanostructures, resulting in the formation of stable, monodisperse nanocolloids (Au@RD NPs and Au@RR NPs) whereas individual constituent molecules were insufficient to yield stable metal NPs. The biological study conducted, both <i>in vitro</i> and <i>in vivo</i>, revealed no acute cytotoxicity (in HaCaT cell lines and zebrafish larval models) but bacteriostatic activity at equivalent doses with potent inhibition of biofilm formation (for a MRSA strain). Noteworthy, the additive antibacterial activity of rose extracts when combined with rifampicin promotes that these attractive inorganic-organic hybrids could be suitable alternatives to combat the acquisition of antimicrobial resistance. This huge application potential was also emphasized by the presence of insignificant changes in the expression of pro-inflammatory cytokine genes (<i>IL-1</i>β, <i>IL-6</i>, and <i>CXCL8</i>) and apoptotic/autophagic associated genes (<i>TP53</i>, <i>MAP1LC3B</i>, and <i>SQSTM1</i>) in treated HaCaT cells at antimicrobial doses. In addition, at the studied doses, the survival of <i>Danio rerio</i> larvae and their proper development (i.e., lack of deformities) endorsed biocompatibility <i>in vivo.</i>