Theoretical Insights into the Carbon Linker Length Effects on the Radical Scavenging Activity of Curcumin

Linker length is one crucial factor affecting the free radical scavenging activity of curcumin. However, identifying an optimal linker length that maintains the desired activity remains challenging. This study offers a thermodynamic evaluation of the influence of linker length on free radical scavenging activity of curcumin, specifically through the hydrogen atom transfer mechanism, in water solvents. Our first-principles calculations reveal that both elongating and shortening the linker promotes a more favorable hydrogen atom transfer at the phenolic O─H and the C─H bond within the linker, respectively. Therefore, linker length should be considered in developing curcumin as a multifunctional medicine.