Effect of cyclodextrin complexation on phenylpropanoids' solubility and antioxidant activity

Area of Science:

• Supramolecular Chemistry
• Pharmaceutical Sciences
• Natural Products Chemistry

Background:

• Phenylpropanoids (PPs) are natural compounds with diverse biological activities.
• Cyclodextrins (CDs) are widely used as hosts for drug delivery and solubility enhancement.
• Understanding host-guest complexation is crucial for optimizing PPs' bioavailability and efficacy.

Purpose of the Study:

• To investigate the complexation behavior of five cyclodextrins with seven phenylpropanoids.
• To characterize the stoichiometry, stability, and thermodynamic parameters of the formed inclusion complexes.
• To evaluate the impact of cyclodextrin complexation on the antioxidant activity of phenylpropanoids.

Main Methods:

• UV-visible spectroscopy and phase solubility studies were employed to determine complex formation constants (K f) and complexation efficiency (CE).
• Molecular modeling was utilized to visualize host-guest interactions and assess complementarity.
• The antioxidant potential of complexed phenylpropanoids was assessed using the DPPH radical scavenging assay.

Main Results:

• All five cyclodextrins formed 1:1 inclusion complexes with the seven phenylpropanoids.
• Complex stability and formation constants were influenced by the nature and position of substituents on the phenylpropanoid phenyl ring.
• A correlation between the intrinsic solubility of phenylpropanoids and the solubilizing capacity of cyclodextrins was observed.
• Encapsulated phenylpropanoids demonstrated retained antioxidant activity, indicating successful preservation of function.

Conclusions:

• Cyclodextrins are effective hosts for phenylpropanoids, forming stable inclusion complexes with tunable properties.
• The study provides insights into structure-affinity relationships governing cyclodextrin-phenylpropanoid interactions.
• Complexation can preserve the antioxidant activity of phenylpropanoids, suggesting potential for enhanced therapeutic applications.