Resveratrol-loaded liposomes: Interaction of resveratrol with phospholipids

The influence of resveratrol encapsulated into liposomes (prepared with a commercial lipid mixture of phospholipids, phospolipon 90NG, using the thin film and proliposome methods) on the structural properties of the liposome membrane was investigated by electron paramagnetic resonance (EPR) spectroscopy, fluorescence spectroscopy, and differential scanning calorimetry. Two fluorophores and two spin probes were used to monitor the characteristics of membranes made from a commercial mixture of phosphatidylcholine. Resveratrol was positioned rather in the inner part of the liposome membranes causing reduction in membrane fluidity. Moreover, resveratrol induced a concentration-dependent decrease in the gel-to-liquid crystalline phase transition temperature (from 41.3 to 38.3 degrees C, for a saturated 1,2-dipalmitoyl-sn-glycero-3-phospatidylcholine bilayer). The antioxidant activity of resveratrol was confirmed by its 95% inhibition of lipid peroxidation, compared to liposomes without resveratrol exposed to the same conditions. Similarly, EPR spectroscopy spin trapping showed an 87% reduction in the spectra intensity of the hydroxyethyl radical, which indicates the efficiency of resveratrol for inhibition of OH radical production. Practical applications: Resveratrol is in the limelight all over the world as a health-beneficial compound widely investigated as natural antioxidant suitable for prevention of human cardiovascular diseases and inhibition of low-density lipoproteins oxidation. Public interest in prevention of diseases through enriched staple foods grows each day. Nonetheless, addition of antioxidants to aqueous-based food can be limited due to their troublesome characteristics. Liposomes are nanocarriers that may be used to overcome the disadvantages and they can be used for food applications. Liposomes could be prepared using only natural components and therefore the new formulations could be quickly implemented. Still, the application of liposomes in food systems is not widespread due to time consuming manufacturing processes and high costs. The presented results provide marks and suggestions to food manufacturers and scientists on how to make broader use of resveratrol-loaded liposomes which add value and improve the quality of existing food products. The influence of resveratrol encapsulated into liposomes (prepared using the thin film and proliposome methods) on the structural properties of the liposome membrane was investigated by electron paramagnetic resonance spectroscopy, fluorescence spectroscopy, and differential scanning calorimetry. The antioxidant activity of resveratrol was confirmed by its inhibition of lipid peroxidation and by spin trapping.