Iron-based dendritic nanostructures incorporating curcumin and ibuprofen for possible multi-therapeutic applications

Abstract

To create multifunctional dendritic nanostructures with antioxidant, antimicrobial, and anti-inflammatory properties, a total of nine dendrimers (D1–D9) were synthesized across three successive generations (G1–G3) with three different terminal groups: chloro, hydroxyl, and ibuprofen. Among these, the ibuprofen-terminated dendrimers across the three generations (G1-D3, G2-D6, and G3-D9) were selected for biological investigation owing to their potential therapeutic relevance. Structural confirmation was achieved for all dendrimers using 1H NMR and ATR-FTIR spectroscopy, while comprehensive physicochemical characterization was performed by SEM, CV, TGA, and fluorescence spectroscopy. SEM analysis revealed generation-dependent surface morphologies, ranging from amorphous-crystalline hybrids in G1-D3 to rough and highly crystalline domains in G3-D9, with G2-D6 exhibiting a uniform amorphous structure suitable for biological applications. TGA profiles indicated consistent three-step thermal degradation across generations, and CV demonstrated generation-dependent shifts in redox potential corresponding to the accumulation of redox-active cyclopentadienyliron centres. Among the synthesized dendrimers, the second-generation ibuprofen-functionalized dendrimer (G2-D6) emerged as the most promising therapeutic candidate. It exhibited superior DPPH radical scavenging activity (IC₅₀ = 16.25 μg/mL), surpassing free curcumin, ibuprofen, and the reference ascorbic acid, likely due to the combined effects of ibuprofen and organoiron moieties. G2-D6 also demonstrated potent antimicrobial and antifungal activity against E. coli, S. aureus, C. albicans, and A. niger, with antifungal performance against A. niger (inhibition zone: 37.0 ± 1.0 mm) exceeding that of Nystatin. Moreover, it achieved up to 96% inhibition in anti-denaturation assays, comparable to pure ibuprofen, highlighting its strong anti-inflammatory potential. These results position G2-D6 as a versatile, multifunctional nanotherapeutic with enhanced efficacy compared to its individual components and other dendrimer generations.