Стабілізація кето-форми куркуміну на поверхні високодисперсного кремнезему через утворення супрамолекулярного комплексу з етонієм

• Datum: 2025
• Hauptverfasser: Барвінченко, В. М., Ліпковська, Н. О., Казакова, О. О.
• Format: Artikel
• Sprache: Ukrainisch
• Veröffentlicht: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2025
• Schlagworte: високодисперсний кремнезем; куркумін; етоній; спектрофотометрія; кето-енольна таутомерія
• Online Zugang: https://surfacezbir.com.ua/index.php/surface/article/view/806
• Назва журналу: Surface

A comprehensive study of adsorption processes and conformational transformations of the natural polyphenol curcumin on the surface of highly dispersed silica A-300 in aqueous solutions of the cationic surfactant etonium within the range of physiological pH values has been carried out. Spectral characteristics of the tautomeric forms of curcumin in solutions and in the adsorbed state were analyzed by electronic absorption spectroscopy (Specord M-40). To theoretically substantiate the interaction mechanisms, quantum-chemical modeling was performed using the density functional theory DFT/B3LYP/6-31G(d,p) with the polarized continuum model (PCM) in the Gaussian 16 software package. The distribution of electrostatic and hydrophobic potentials was calculated using the Flare™ software package. The main objective of the work was to clarify the mechanisms determining the tautomeric (keto–enol) equilibrium of curcumin in surfactant solutions and at the silica/solution interface. The mechanism of stabilization of the biologically active ketone form of curcumin on the surface of nanosilica was established. In contrast to known micellar systems, in which the enol form dominates, it was shown that stabilization of the ketone form occurs through the formation of a specific supramolecular complex Cur–K•Et in the premicellar solutions of etonium. The formation of the complex is accompanied by the screening of the electron-donor groups of curcumin and the formation of a localized positive electrostatic potential, which promotes the adsorption of the complex on the silica surface with dissociated silanol groups Si–O⁻. The obtained results open up new prospects for controlled delivery and increased bioavailability of the antioxidant (ketone) form of curcumin. The revealed regularities make it possible to develop practical recommendations for creating new curcumin-based drug forms on nanosilica, as well as for the development of methods for its concentration and sorption–photometric or visual–test determination.