Extraction of phospholipid-rich fractions from egg yolk and development of liposomes entrapping a dietary polyphenol with neuroactive potential

A new protocol to obtain egg yolk phospholipids in ethanol is presented. Rutin-phospholipids nanoliposomes were prepared and characterized. The procedure takes advantage of the different solubility of egg yolk lipids in ethanol and acetone at low temperature, to efficiently obtain a phospholipid-rich fraction of high purity degree. The phospholipid content in the final fraction is 208.65 +/- 26.46 mu mol/g fresh egg yolk (16%), accounting for ca. 96% of the extract's dry weight. The phospholipid-rich fraction contains cholesterol (0.069-0.082 cholesterol/phospholipid molar ratio), and vestigial amounts of lutein and zeaxanthin (89.24 +/- 9.76 and 14.9 +/- 2.16 ng/g of fresh egg yolk, respectively). Saturated fatty acids dominate the extracted phospholipids (50% of eggs total yolk phospholipids), the levels of monounsaturated ranging from 20 to 25%, and polyunsaturated up to 35%. Rutin-liposomes, prepared with phospholipid-rich fraction, presented mean diameter < 140 nm, negative surface charge (Zeta potential similar to - 13 mV), and entrapment efficiency of rutin up to 87%. In human neuroblastoma cell line SH-SY5Y, rutin-liposomes (lipid 25 mu M + rutin 16.7 mu M) attenuated glutamate-induced cytotoxicity, in part by reducing the formation of intracellular reactive species, pointing to their potential application as new functional neuroprotective agents.