Comparison between Free and Encapsulated Form of Epicatechin in Liposomes and In Polymeric Nanoparticles Against the Paraquat-Induced Toxicity of NRK-52E Cells

Both liposomes and polymeric nanoparticles have lately been utilized as carriers of conventionally prescribed medications with the aim of improving their activity in various ways. Epicatechin is a flavonoid with a limited bioavailability that can be found in natural sources. It is somewhat water soluble. However, because of its poor absorption and quick metabolism, it cannot function as it is expected. This work sought to enhance the pharmacokinetic features of epicatechin by encapsulating it in polylactic acid nanoparticles and liposomes. Liposomes were formed by the hydration of a lipid film to prepare large multilamellar vesicles, followed by membrane extrusion to formulate smaller unilamellar vesicles. On the other hand, polymeric nanoparticles were produced by double emulsification solvent diffusion method using polylactic acid as the polymer. Both products were then characterized for their particle size, zeta potential, drug loading, antioxidant activity, toxicity on cell lines (NRK-52E cells) and protection against paraquat oxidation. The mean particle size of liposomes was 183.8 ± 80.1 nm and for polylactic acid nanoparticles it was 350.9 ± 87.4 nm. Their surface zeta-potentials were -11.3 ± 3.93 and -32.9 ± 7.54 mV; respectively. The encapsulation of epicatechin in liposomes was 10.23 ± 1.54% and in polylactic acid nanoparticles 5.35 ± 3.35% (%encapsulation efficiency = 18.09 ± 1.95%). Microscopic images presented both sorts of nanoparticles to be sphere-shaped. Encapsulation of epicatechin into both liposomes and polylactic acid nanoparticles enhanced the % internalisation remarkably from 4.18 ± 0.03% to 27.05 ± 1.07% and 36.29 ± 0.09%; respectively. The toxicity test found all three forms not to be harmful to the NRK-52E cells within the concentration ranges tested. Examining the in vitro activity results showed that the same concentration of epicatechin in the liposomal form showed more protection against paraquat than epicatechin in its free form. Moreover, a lower epicatechin concentration was used in the polylactic acid nanoparticle form and still found to be more protective. From these results it can be concluded that epicatechin-loaded liposomes and polylactic nanoparticles offer protection to NRK-52E cells against paraquat induced toxicity.