Abstract:

Resveratrol is a natural polyphenol and phytoalexin with anti-inflammatory, anti-oxidant, anti-cancer, and neuroprotective effects. However, resveratrol exhibits low solubility, light sensitivity, poor absorption by oral administration, and short cycle time, which greatly limit its applications in medicine and the food industry. To overcome these limitations, a nano-resveratrol liposome (RES-Lip) was prepared. As a drug carrier, liposomes have many advantages such as good targeting properties, low toxicity, biocompatibility, and long-term sustained release. In liposomal studies, the oil-water (n-octanol-water) partition coefficient (P_o/w) is often used to predict the encapsulation and drug loading efficiencies. This method focuses on the lipophilicity of the drug, reflecting its hydrophobic action while ignoring the biological properties of the biofilm. The liposome-water partition coefficient (P_lip/w) reflects the structure of the biofilms and its interaction with drugs governed by factors including hydrophobicity, electrostatic forces, and hydrogen bonding. Herein, RES-Lip was successfully prepared using a rotary-evaporated film-ultrasonication method and subsequent characterization by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The effects of the membrane to material ratio (lecithin to cholesterol mass ratio m_PC : m_Chol = 5 : 1, 8 : 1, 10 : 1, and 12 : 1) and drug to lipid ratio (drug to lecithin mass ratio m_RES : m_PC = 1 : 25, 1 : 40, 1 : 50, and 1 : 60) of nano-resveratrol liposomes on the liposome-water partition coefficient (P_lip/w) were determined. Changes in the oil-water partition coefficient (lgP_o/w) and liposome-water partition coefficient (lgP_lip/w) as a function of pH were also determined. In addition, the Gibbs free energy between the drug and phospholipid bilayer membrane in RES-Lip was calculated. The results showed that RES-Lip adopted a spherical vesicle structure with a particle size of approximately 100 nm. When the membrane to material ratio was 10 : 1 and the drug to lipid ratio was 1 : 40, lgP_lip/w was maximized, indicating that the combined forces between RES and the phospholipid membrane were the highest at these ratios. The trends of lgP_o/w and lgP_lip/w as a function of pH were the same, indicating that the main interaction force between RES and the phospholipid membrane was the hydrophobic effect with secondary interaction forces of hydrogen bonding and electrostatic interaction. The Gibbs free energy between the RES and liposome membrane in RES-Lip was determined to be −17.07 kJ·mol⁻¹.

Key words: Resveratrol, Liposome, Oil-water partition coefficient, Liposome-water partition coefficient, Gibbs free energy