A Comparative Study of Reaction Sites of Planar Rhein: A density Functional Theory Study

Rhein (C15H8O6), a natural hydroxyanthraquinone compound widely found in traditional Chinese medicinal herbs, exhibits a range of pharmacological activities due to its unique planar structure, including anticancer, anti-inflammatory, antimicrobial, and anti-Alzheimer’s disease effects. This study employed density functional theory to comprehensively analyze the reactive sites of the rhein molecule using various theoretical methods, including: localized orbital locator (π-electron), Mulliken charges, electrostatic potential, atomic local ionization energy, and dual descriptor. This study not only provides a molecular-level mechanism for understanding the bioactivity of rhein but also offers theoretical guidance for the development of novel rhein derivatives to enhance their biological activities.