Abstract
[Display omitted]
•Hibiscus sabdariffa stem (HSS) aqueous extract mediated the facile, one-pot green synthesis of silver nanoparticles (AgNPs).•AgNPs were tolerated by examined healthy mice and activated Nrf-2/HO-1 pathway.•AgNPs exerted an apoptotic anti-ovarian cancer activity with IC50 value 6 times more than IC50 against normal cells.•Conjugates of polydopamine-coated AgNPs were covalently linked to moxifloxacin as well as gatifloxacin.•Conjugate showed an augmented antibiofilm activity against Gram-negative biofilms compared to free antibiotic or AgNPs alone.
Silver nanoparticles (AgNPs) could be employed in the combat against COVID-19, yet are associated with toxicities. In this study, biogenic and biocompatible AgNPs using the agro-waste, non-edible Hibiscus sabdariffa stem were synthesized. Under optimized reaction conditions, synthesized green AgNPs were crystalline, face cubic centered, spherical with a diameter of around 17 nm and a surface charge of −20 mV. Their murine lethal dose 50 (LD50) was 4 folds higher than the chemical AgNPs. Furthermore, they were more murine hepato- and nephro-tolerated than chemical counterparts due to activation of Nrf-2 and HO-1 pathway. They exerted an apoptotic anti-ovarian cancer activity with IC50 value 6 times more than the normal cell line. Being functionalized with polydopamine and conjugated to either moxifloxacin or gatifloxacin, the conjugates exerted an augmented antibiofilm activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii biofilms that was significantly higher than antibiotic alone or functionalized AgNPs suggesting a synergistic activity. In conclusion, this study introduced a facile one-pot synthesis of biogenic and biocompatible AgNPs with preferential anti-cancer activity and could be utilized as antibiotic delivery system for a successful eradication of Gram-negative biofilms.