Immobilization of Olive Leaf Extract with Chitosan Nanoparticles as an Adjunct to Enhance Cytotoxicity

We immobilized the olive leaf extract (OLE) with chitosan nanoparticles (CNPs) by optimizing the effect of various immobilization conditions, and OLE-loaded CNPs (OLE-CNPs) were then elaborately characterized physicochemically by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM). Under optimal conditions, CNPs were able to accommodate the OLE with a loading capacity of 97.5%. The resulting OLE-CNPs had a spherical morphology, and their average diameter was approximately 100 nm. The cytotoxic influence, cell cycle distribution, and apoptosis stage of OLE and OLE-CNPs were analyzed on lung carcinoma (A549) and breast adenocarcinoma (MCF-7) cell lines. In an in vitro cytotoxic assay, IC₅₀ values of OLE-CNPs were determined to be 540 μg/mL for A549 and 810 μg/mL for MCF-7. The treatment of both A549 and MCF-7 with OLE-CNPs caused the highest cell arrest in G0/G1 in a dose-independent manner. OLE-CNPs affected cell cycle distribution in a manner different from free OLE treatment in both cancer cells. A549 and MCF-7 cells were predominantly found in the late apoptosis and necrosis phases, respectively, upon treatment of 1000 μM OLE-CNPs. Our results suggest that CNPs enhance the utility of OLEs as nutraceuticals in cancer and that OLE-CNPs can be utilized as an adjunct to cancer therapy.