Desenvolvimento de desodorante à base de óleos essenciais de canela e melaleuca: uma alternativa sustentável para a higiene pessoal

Abstract

Daily use of deodorants is common in personal hygiene routines, especially in tropical climates. However, many commercial products contain compounds such as aluminum salts, triclosan, and parabens, which are associated with dermatitis, hormonal imbalances, and environmental bioaccumulation. In light of these concerns, this study aimed to develop a natural liquid spray deodorant formulation based on essential oils (EOs) of Melaleuca alternifolia (tea tree) and Cinnamomum cassia (cinnamon). The formulation also included grain alcohol, distilled water, and aloe vera (Aloe vera) extract at two concentrations (5% and 10%), resulting in two final deodorant formulations. The antimicrobial activity of the EOs was investigated against Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis, and Corynebacterium sp. using disk-diffusion and broth microdilution assays. Antioxidant activities were evaluated using ABTS•⁺, DPPH•, FRAP, and Folin-Ciocalteu methods. The disk-diffusion assay yielded inconclusive results, as one of the plates showed no bacterial growth, preventing the measurement of inhibition zones. Therefore, the interpretation of results was based on the broth microdilution method, in which cinnamon EO showed higher antimicrobial activity, presenting lower minimum inhibitory concentrations. In the antioxidant analyses (ABTS•⁺, DPPH•, and FRAP), both oils exhibited activity. In the ABTS•⁺ assay, tea tree EO showed higher antioxidant activity (7.006 μg TE/mg). In the DPPH• assay, cinnamon EO performed better (0.0128 μmol TE/mg). In the FRAP assay, tea tree EO showed greater reducing capacity (0.057 μmol Fe²⁺). In the Folin-Ciocalteu assay, tea tree EO had a higher total phenolic content (28.77 μg GAE/mg). Among the two formulations tested, the deodorant containing 10% aloe vera extract demonstrated greater physicochemical stability over 30 days, maintaining pH, color, and absence of phase separation. The combination of cinnamon and tea tree essential oils, together with the plant extract, showed potential for developing natural deodorants with antimicrobial and antioxidant activity, supporting the feasibility of safer and more sustainable alternatives to conventional products.