In Vitro Antioxidant Stability and Infrared Characterization of a Cosmetic Formulation with Peruvian Bioactive Compounds

This study assessed the structural stability and in vitro antioxidant capacity of a cosmetic formulation incorporating sangre de grado extract (Croton lechleri Muell) and vegetable oils from aguaje (Mauritia flexuosa L.f.), aguaymanto (Physalis peruviana L.), super sacha inchi (Plukenetia huayllabambana sp. nov.), and sacha inchi (Plukenetia volubilis L.), sourced from Peruvian biodiversity. Structural characterization was conducted using Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) on the formulation at the initial time point (ASC T0) and after six months under accelerated stability conditions (ASC T6). Characteristic absorption bands corresponding to carbonyl, ether, and hydroxyl functional groups were observed, confirming the structural integrity of the lipid–polymeric components within the emulsifying system. Antioxidant activity was evaluated using DPPH and ABTS assays, with IC50 values comparable to those of a commercially available cream. In the DPPH assay, ASC T6 exhibited IC50 of 5744.8571 μg/mL, comparable to a commercial formulation (5641.1585 μg/mL). In the ABTS assay, ASC T0 demonstrated antioxidant activity statistically equivalent (p > 0.05) to that of the commercial cream, with IC50 values of 410.2358 and 420.2202 μg/mL, respectively. In conclusion, the preservation of antioxidant activity is attributed to the structural integrity of the formulated system, which stabilized and retained synergistic interactions of the antioxidants. Future studies should explore the incorporation of additional antioxidants and include in vivo instrumental assessments of stability and efficacy.