Curcumin- and Fish Oil-Loaded Spongosome and Cubosome Nanoparticles with Neuroprotective Potential against H2O2-Induced Oxidative Stress in Differentiated Human SH-SY5Y Cells

Many phytochemical antioxidant compounds, including curcumin (CU), are water-insoluble and thus require delivery carriers in order to increase their bioavailability for in vivo applications. Oxidative stress-related apoptosis is a common cause for the neuronal loss in the progression of neurodegenerative diseases. Lipid nanoparticles (NPs) with internal self-assembled liquid crystalline structures present strong interest as safe drug delivery systems for neuronal regeneration through combination therapies. Here, we report spongosome and cubosome lipid NPs, which co-encapsulate CU and fish oil (FO), rich in omega-3 polyunsaturated fatty acids. The performed structural investigation by synchrotron small-angle X-ray scattering evidenced the liquid crystalline organization of the self-assembled NPs. The encapsulation efficiency for CU in the lipid nanocarriers was found to be higher as compared to that reported for polymer-based carriers. The cytotoxicity of the blank and antioxidant-loaded nanocarriers was negligible at lipid concentrations 300 and 500 nM. Morphological changes were observed for neuronally derived human SH-SY5Y cells subjected to damage by reactive oxygen species (ROS) upon exposure to hydrogen peroxide. Using flow cytometry, we quantified the effects of CU and FO, co-encapsulated in spongosome and cubosome lipid NPs on the response of differentiated SH-SY5Y cells to H2O2-induced oxidative stress. Measurements of the intracellular ROS levels (using a 2', 7'-dichlorodihydrofluorescein diacetate probe) and of apoptotic cells (using an Annexin V-PE/SYTOX-green assay) were performed to compare the neuroprotective potential of the liquid crystalline spongosome and cubosome nanocarriers to that of ethanolic solutions or aqueous suspensions of the CU/FO mixtures. The results indicated that dual drug-loaded cubosomes may be suitable for combination treatments against neurodegenerative disorders.