Sucupira Oil-Loaded Nanostructured Lipid Carriers (NLC): Lipid Screening, Factorial Design, Release Profile, and Cytotoxicity.

Essential oils are odorant liquid oily products consisting of a complex mixture of volatile compounds obtained from a plant raw material. They have been increasingly proven to act as potential natural agents in the treatment of several human conditions, including diabetes mellitus (DM). DM is a metabolic disorder characterized by chronic hyperglycemia closely related to carbohydrate, protein and fat metabolism disturbances. In order to explore novel approaches for the management of DM our group proposes the encapsulation of sucupira essential oil, obtained from the fruits of the Brazilian plants of the genus Pterodon, in nanostructured lipid carriers (NLCs), a second generation of lipid nanoparticles which act as new controlled drug delivery system (DDS). Encapsulation was performed by hot high-pressure homogenization (HPH) technique and the samples were then analyzed by dynamic light scattering (DLS) for mean average size and polydispersity index (PI) and by electrophoretic light scattering (ELS) for zeta potential (ZP), immediately after production and after 24 h of storage at 4 °C. An optimal sucupira-loaded NLC was found to consist of 0.5% (m/V) sucupira oil, 4.5% (m/V) of Kollivax® GMS II and 1.425% (m/V) of TPGS (formulation no. 6) characterized by a mean particle size ranging from 148.1 ± 0.9815 nm (0 h) to 159.3 ± 9.539 nm (at 24 h), a PI from 0.274 ± 0.029 (0 h) to 0.305 ± 0.028 (24 h) and a ZP from -0.00236 ± 0.147 mV (at 0 h) to 0.125 ± 0.162 (at 24 h). The encapsulation efficiency and loading capacity were 99.98% and 9.6%, respectively. The optimized formulation followed a modified release profile fitting the first order kinetics, over a period of 8 h. In vitro cytotoxicity studies were performed against Caco-2 cell lines, for which the cell viability above 90% confirmed the non-cytotoxic profile of both blank and sucupira oil-loaded NLC.

Protective effect of sucupira oil nanoemulsion against oxidative stress in UVA-irradiated HaCaT cells.

OBJECTIVES: Bioactive molecules derived from natural products combine the ability to absorb UV light and act as antioxidants. We developed an oil-based sucupira (native species of the Brazilian cerrado) nanoemulsion (NE) using a high-energy emulsification method and assessed its effectiveness in vitro. METHODS: An easily scalable high-pressure homogenization method was used to prepare the formulation. NE droplets mean diameter, pH, stability, conductivity and morphology were analysed. Formulation bioactivity was assessed using HaCaT cells. KEY FINDINGS: The formulation presented suitable pH and size for topic administration and was stable for over 90 days upon storage at 4, 25 and 45°C. The NE showed protective effect against oxidative stress and reduced levels of UVA-induced pro-inflammatory cytokines IL-6 and IL-8. CONCLUSIONS: A novel, stable and easily prepared formulation was obtained for encapsulation of sucupira oil. The protective effect of the formulation by cytokine inhibition in the early stage of the inflammatory process was shown in vitro. Combined with the antioxidant effect by inhibition of reactive oxygen species, the use of sucupira oil NE for prevention and treatment of UVA-induced stress could contribute to decrease the effects of UV radiation on skin ageing.