Morin-loaded nanoceria as an efficient nanoformulation for increased antioxidant and antibacterial efficacy

Nanoparticles (NPs) are widely utilized as an effective carrier for naturally occurring biologically active hydrophobic molecules with a potential to enhance antioxidant and antibacterial activities. Here, a positively charged amine-functionalized ceria nanoparticles (CeO 2 -NH 2 NPs) were prepared first, and then a natural flavonoid, morin was adsorbed on the surface of NPs via metal–ligand coordination to form a nanohybrid (morin-CeO 2 -NH 2 ). The CeO 2 -NH 2 NPs displayed almost spherical shape with size of around 3–4 nm, along with the presence of Ce, O, N, C, and Si. The NPs showed ~ 10% drug (morin) loading content, and a sustained release pattern of morin under physiological conditions. The nanohybrids showed excellent free radical (DPPH, superoxide, and hydrogen peroxide) scavenging properties in both cell-free systems as well as in intracellular conditions. Cytotoxicity assessment revealed that the nanohybrids were slightly toxic up to the concentration of 50 μg/mL in normal human kidney epithelial cells. Further, the nanohybrids showed a significant growth inhibition against the tested Gram-negative as well as Gram-positive bacteria due to the production of excessive reactive oxygen species (ROS), DNA degradation, and membrane damage. However, those in vitro assays showed that the nanohybrid exhibited the maximum effect in imparting the antioxidant and antibacterial activity among all the treatment groups. All these results highlighted that the nanoceria-mediated drug delivery systems could help to increase the antioxidant and antibacterial potential of morin. Graphical abstract