Structural characterization of inclusion complex of stigmasterol with alpha-cyclodextrin using spectroscopy and molecular modeling

Abstract

Background: Stigmasterol possesses numerous physiological effects and is used as food supplements and behaves as a pharmaceutical agent. It exhibits anticancer effects against various cancers. The usefulness of the stigmasterol is restricted due to its poor solubility. To overcome this and enhance the solubility and bioavailability of this phytosterol, molecular encapsulation is utilized to augment the desirable properties of stigmasterol. This research work aims to investigate the interaction between stigmasterol and alpha-cyclodextrin (α-CD) in aqueous solution as well as in solid state and experimentally examined by spectral techniques. Methods: The liquid complexes are characterized by ultraviolet (UV)-visible spectroscopy and solid inclusion complexes are characterized by Fourier transformer infrared resonance and 1H nuclear magnetic resonance spectroscopy. The thermal behavior of the complex is analyzed by differential scanning calorimeter. Phase solubility studies are done to learn the solubility of the newly synthesized complex. Results: Formation constant from UV-visible analysis is found to be 569 M−1 by Benesi–Hildebrand equation. The solubility constant is calculated to be 52 M−1. The results obtained prove the inclusion which is confirmed through molecular docking studies. Conclusion: The newly synthesized inclusion complex is a potent pharmaceutical agent in drug formulation as stigmasterol solubility is enhanced when included in the cavity of α-CD.