Resveratrol‐loaded liposomes: Interaction of resveratrol with phospholipids

Abstract

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°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.

Impact of selected polyphenolics on the structural properties of model lipid membranes – a review

“…Figure 11: Effects of resveratrol at different molar ratios (as indicated) on the oxidation kinetics of BODIPY 581/591 C 11 , a fluorescent fatty acid analogue that acts as a lipophilic probe (from Balanc et al (2015)). …”

“…MLVs were prepared with the commercial P90NG lipid mixture using two methods: a thinfilm method (Lasch, Weissig, & Brandl, 2003) and a proliposome method (Perrett et al, 1991), with the location of resveratrol in the liposomal membranes investigated using fluorescence spectroscopy, EPR spectroscopy and DSC (Balanc et al, 2015). To determine the relative benefits of the incorporation of resveratrol into phospholipid bilayers, the dose-dependency and timedependency of the oxidation kinetics of encapsulated resveratrol were determined based on the BODIPY 581/591 C 11 fluorochrome, a lipophilic fluorescent fatty acid analogue.…”

“…By acting as a radical scavenger, resveratrol can protect liposomes made of this commercial mixture of lipids (Fig. 11) from lipid peroxidation, and can efficiently inhibit the production of OH radicals (Balanc et al, 2015).…”

Fluorescence analysis of liposomal membranes permeability

“…Razlike su smatrane statistički značajnim pri p < 0,05. Dobijeni rezultati su bili očekivani zato što povišena temperatura uzrokuje povećanje mobilnosti lipida, te posledično povećanje permeabilnosti dvoslojne membrane [9]. Za svaki tip fosfolipida vrednost fluorescentne anizotropije je viša u gel fazi, pri čemu dolazi do pada vrednosti nakon dostizanja temperature faznog prelaza (Tm, prelazak iz gel faze u tečno-kristalnu fazu).…”

“…Međutim, vrednosti anizotropije čistih POPC i Lipoid H lipozoma bile su statistički značajno niže u poređenju sa DPPC lipozomima (p < 0,05). Dobijeni rezultati su u skladu sa literaturnim podacima, jer je pokazano da DPPC formira homogeni i rigidni lipidni dvosloj, sa pravilnim rasporedom ugljovodoničnih lanaca, dok mešavina različitih fosfolipida (kao što je slučaj sa Lipoid H komercijalnom smešom) stvara manje homogenu lipozomalnu mem branu, za koju je karaktertična veća permeabilnost [9,10] Rezultati dobijeni prilikom analize lipozoma sa sterolima (holesterol i β-sitosterol) pokazuju da ispod vrednosti Tm čistog DPPC, dodavanje holesterola i βsitosterola rezultira smanjenjem anizotropije DPH, u poređenju sa čistim DPPC lipozomima (slike 4A i 5A). Međutim, iznad ove temperature, lipozomi sa sterolima su dali više vrednosti anizotropije nego sam DPPC.…”