Andiroba Oil ( Carapa guianensis Aublet) Gel-Based Nanoemulsion: Development, Characterization, and In Vitro Evaluation in Wound Healing-Related Cells

Abstract Andiroba oil (Carapa guianensis Aublet) is widely used in traditional medicine due to its anti-inflammatory and reported wound-healing properties. In this study, we developed and characterized andiroba oil-based nanoemulsions (NeAnd) and gel-based nanostructured formulation (NeAndG) to investigate their physicochemical stability and initial in vitro biological effects in wound healing-related cells. Chemical characterization by GC-MS confirmed the presence of limonoids (including gedunin and its derivatives), β-sitosterol, and oleic acid in andiroba oil composition, compounds associated with anti-inflammatory and regenerative properties. The nanoemulsions exhibited hydrodynamic diameters <200 nm, low polydispersity indices (<0.3), and a negative surface charge, indicating a homogeneous and stable nanostructured system. After incorporation into the Carbopol hydrogel, the nanodroplets maintained nanoscale size while exhibiting a markedly increased negative ζ potential (≈ −74 mV), suggesting enhanced colloidal stability. Long-term stability assays demonstrated that the gel matrix significantly improved thermal stability and prevented nanodroplet aggregation compared with the nanoemulsion alone during storage (4, 25, and 37 °C for 120 days). In vitro assays using human keratinocytes (HaCaT) and fibroblasts (HGF) showed a dose-dependent decrease in cell viability. Scratch assay analysis revealed no significant enhancement of cell migration compared with controls, suggesting that the biological activity of andiroba oil in this context may involve mechanisms other than cell migration. Overall, these results demonstrate that the andiroba oil nanogel represents a stable and biocompatible nanoplatform suitable for further investigation in wound healing-related studies.