Beyond Curcumin: Structural Modification Strategies to Improve Stability, Bioavailability, and Antiproliferative...

Curcumin is a versatile natural compound that has been extensively studied for its potential activity in cancer models. However, its clinical development faces challenges, including poor water solubility, chemical instability under physiological conditions, rapid metabolism, and limited systemic bioavailability. These issues have driven efforts to modify the curcumin structure to enhance stability, pharmacokinetics, and target interaction, while preserving or improving its antiproliferative effects. This review highlights key medicinal chemistry strategies for creating analogs beyond curcumin, including (i) monocarbonyl variants that replace the β-diketone group to improve stability, (ii) aromatic ring modifications that adjust electronic properties, lipophilicity, and cellular entry, (iii) prodrug designs that conceal phenolic groups to increase solubility or permeability, and (iv) hybrid molecules and conjugates for dual targeting or better delivery. Additionally, we discuss metal-curcumin(oid) complexes as promising options to modify stability, redox activity, and biological effects in cancer models. We also propose a basic evaluation toolkit to support more consistent comparisons among analogs, emphasizing the need to report chemical stability, microsomal metabolism, selectivity, and in vivo exposure, alongside in vitro viability/proliferation readouts and, where available, orthogonal cytotoxicity endpoints. Rather than treating beyond-curcumin chemistry as a catalog of potency-improving modifications, this review frames the major scaffold classes in terms of developability, evidentiary burden, and translational pragmatism. Overall, successful translation will depend less on isolated IC₅₀ gains and more on standardized profiling and alignment of mechanism claims with achievable exposure.