Improved Hypericin solubility via β-cyclodextrin complexation: Photochemical and theoretical study for PDT...

Area of Science:

• Biochemistry
• Materials Science
• Photochemistry

Background:

• Hypericin (HY) is a lipophilic photosensitizer used in photodynamic therapy (PDT).
• Poor solubility of HY limits its bioavailability and application in PDT.
• Supramolecular complexation with cyclodextrins (CDs) can enhance photosensitizer solubility.

Purpose of the Study:

• To create an inclusion complex of hypericin (HY) with beta-cyclodextrin (β-CD).
• To assess the solubility, photophysical properties, and phototoxicity of the HY-β-CD complex for PDT.
• To evaluate the potential of the HY-β-CD complex in cancer treatment.

Main Methods:

• Co-solvent method used to form the HY-β-CD inclusion complex.
• Solubility, fluorescence quantum yield (ϕ_f), and singlet oxygen quantum yield (ϕ_Δ) were measured.
• Phototoxicity was evaluated in MCF7 cells, assessing cell uptake and therapeutic efficacy.

Main Results:

• The HY-β-CD complex significantly improved HY solubility.
• The complex retained essential photophysical properties (ϕ_f =0.115, ϕ_Δ= 0.23) and showed a spontaneous complexation process (ΔG < 0).
• The β-CDHY complex demonstrated 27% greater phototoxicity than free HY in MCF7 cells, indicating enhanced cellular uptake.

Conclusions:

• The HY-β-CD inclusion complex enhances hypericin solubility and retains crucial photophysical properties for PDT.
• The complex exhibits increased phototoxicity and improved cell uptake compared to free hypericin.
• This HY-β-CD complex holds significant potential for future applications in photodynamic therapy.