DEVELOPMENT, CHARACTERIZATION AND CYTOTOXICITY OF BURITI OIL (MAURITIA FLEXUOSA) NANOEMULSIONS ON BREAST CANCER AND NORMAL FIBROBLAST CELLS IN VITRO

Marina C. Sampaio, Marcela G. Landim, Patrícia L. Costa, Beatriz C. de A. O. Faria, Alicia S. Ombredane, Ricardo B. Azevedo, Graziella A. Joanitti

The purpose of this study was to synthesize, characterize, and evaluate the activity of Buriti oil (Mauritia flexuosa) nanoemulsions (BuNEs) against breast cancer cells (MCF-7) and normal fibroblast cells (NIH/3T3) in vitro. Different proportions of Buriti oil and surfactant were incorporated in (a) chitosan solution (for BuNE+); (b) in deionized water (for BuNE-); (c) with N-(2,3-Dioleoyloxy-1-propyl) trimetilammonium–DOTAP- (for BuNE+DOTAP); or (d) with Polyethylene glycol– PEG- (for BuNE+PEG). Then, the reagents were sonicated (20 kHz) for 5 minutes under ice bath. The nanoemulsions were characterized by dynamic light scattering during 30 days. For cell viability evaluation, cells were seeded in 96-well plates (5×103 cells/well for MCF-7 and 3×103 cells/well for NIH/3T3) and treated with 90, 180, and 360 µg/mL of each BuNEs or free Buriti oil. After 24 hours, the treatments were removed and cell viability was analyzed by MTT assay. Statistical analysis was performed with ANOVA (Bonferroni post-test). All BuNEs were stable and showed a mean hydrodynamic diameter ≤167 nm and medium polydispersity index ≤0.289. A significant dose-dependent decrease on MCF-7 cell viability was observed with all BuNEs treatments (p<0.001). BuNE- and BUNE+DOTAP reduced cell viability in ~50% at 360 µg/mL (p<0.001), while the free oil showed a less expressive reduction in the same concentration (18%; p<0.01). Interestingly, BuNEs showed low cytotoxicity to NIH/3T3 normal cells (~20%; p<0.001) even when treated with 360 µg/mL. Overall, stable BuNEs were formulated successfully and presented a significant higher cytotoxicity on cancer cells when compared with normal cells. In conclusion, BuNEs formulations are promisor candidates to be employed as adjuvant tools in conventional breast cancer therapies.


Keywords: Buriti oil, Mauritia flexuosa, nanoemulsion, MCF-7, NIH/3T3, cell viability, nanotechnology.