Curcumin-loaded proliposomes via glycerol-infused: Mechanism, stability and antioxidant activities

Liposome systems are highly advantageous for encapsulating curcumin with improved solubility and bioactivity. However, the conventional preparation of curcumin-loaded nanoliposomes is often hindered by the complex synthesis process, specialized equipment and the use of toxic organic solvents. This study presents a simple and green method for preparing curcumin-loaded nanoliposomes. Proliposomes were initially prepared by dissolving phospholipids in glycerol at a temperature exceeding the phase transition temperature (T_m) of the phospholipids. Differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR) analyses revealed that glycerol reduces the T_m value by disrupting hydrogen bonds with phospholipids. Curcumin was incorporated into the proliposomes through direct heating (15 mg/6 g proliposomes, stirred at 90 °C for 15 min), followed by hydration at room temperature to produce stable curcumin-loaded nanoliposomes. The resulting nanoliposomes exhibited high resilience to pH, ionic strength and heat treatment, with the encapsulation efficiency of 98.04 % for curcumin. During simulated digestion, the curcumin-loaded nanoliposomes exhibited exceptional gastrointestinal stability and increased the bioaccessibility of curcumin to 52.19 %. Compared to free curcumin, curcumin-loaded nanoliposomes mitigated oxidative stress in Lo-2 cells and displayed superior antioxidant activity. This study offers a green and efficient approach for synthesizing curcumin-loaded nanoliposomes and provides the novel insights on the nutrient delivery systems.