Fig. 2

Iron chelating ability of curcumin in vitro. A, B The chemical structure of curcumin and the binding site where curcumin binds to iron ions (Fe²⁺ and Fe³⁺). C, D UV–Vis spectrum, peaked at 435 nm, to demonstrate iron chelation by curcumin in a concentration-dependent manner. Ultrasmall iron oxide nanoparticles (IONPs, 10 μM iron) were used as an iron source, and the absorption at 435 nm was quantified in D. E Prussian blue staining was used to reveal Fe accumulation after IONP or IONP + Cur@SF NPs treatment in RAW 264.7 cells