Inclusion Complexes of Colchicine with Acyclic Cucurbit[ <i>n</i> ]urils to Improve Its Photostability and Retain Anticancer Activity

Colchicine is known for its significant anti-inflammatory, antigout, and anticancer activities, and recent research has increasingly focused on its potential cardiovascular protective effects. However, its poor photostability restricts its broader applications. To address this limitation, supramolecular host-guest encapsulation has emerged as an effective strategy for enhancing the stability of guest molecules. In this study, two types of acyclic cucurbit[<i>n</i>]urils (ACBs, referred to as M1 and M2) were synthesized as host molecules, while colchicine was utilized as the guest molecule to form inclusion complexes via host-guest encapsulation. The binding behavior between colchicine and ACBs was systematically investigated using various techniques, including ¹H NMR, 2D-ROESY NMR, XRD, FT-IR, and molecular docking. The results confirmed the successful formation of host-guest inclusion complexes. Notably, the encapsulation of colchicine with ACBs (M1 and M2) significantly improved its stability under sunlight and UV light exposure. Furthermore, the anticancer activity of colchicine remained intact after the formation of inclusion complexes, demonstrating that the encapsulation process preserved its therapeutic efficacy while enhancing its photostability. These findings highlight a promising research strategy for extending the application and development of colchicine in various fields.