Institution: University of Brasilia
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.
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