Desenvolvimento de ativos multifuncionais com potencial uso cosmético a partir de Lippia thymoides Mart. & Schauer por métodos e solventes verdes

Abstract

The growing consumer preference for sustainable and ―clean‖ cosmetic formulations— free from parabens, petroleum derivatives, and animal-derived ingredients—highlights the relevance of this research. Advanced extraction techniques, such as ultrasound, fermentation, and supramolecular solvents, offer significant advantages by reducing energy consumption and avoiding the use of harmful solvents, thus aligning with sustainability principles.This study aimed to optimize green extraction methods, such as probiotic fermentation and supramolecular solvent systems, to obtain bioactive compounds from Lippia thymoides Mart. & Schauer, with the goal of developing natural actives and preservatives for the cosmetic industry. Fermentation was carried out with the bacterium Lacticaseibacillus rhamnosus for 24 hours, using an experimental design known as Central Composite Rotational Design, which allows the evaluation of both isolated and combined effects of variables—the amount of plant material and the inoculum concentration of the microorganism—at five different levels. For supramolecular solvents, the extracts were obtained by spontaneous coacervation of octanoic acid in an acidified hydroalcoholic solution, followed by extraction. The results highlighted the superior performance of L. rhamnosus in antioxidant assays, particularly in the DPPH method, where fermentation significantly increased antioxidant activity. The optimized condition (3.0% plant material, 1x10³, ⁵ colonyforming units per milliliter, 24 hours) yielded extracts with high antioxidant and antimicrobial activity. The antioxidant capacity, measured by TEAC, was 421 ± 7.2 μmol/g for the DPPH assay and 154 ± 5.7 μmol/g for the ABTS assay—values higher than those obtained without fermentation. The minimum inhibitory concentration (MIC) of fermented extracts was 3.125% of the fermentate, equivalent to 1.09 mg/mL of dry extract, required to inhibit the growth of Staphylococcus aureus. The supramolecular extracts of L. thymoides also demonstrated potential as photoprotective agents, with a correlation between phenolic content, particle size, and the protection factor against ultraviolet B radiation. The supramolecular solvents exhibited the highest antimicrobial activity, with the lowest concentration required to inhibit the growth of Staphylococcus aureus and Escherichia coli being 0.05 mg/mL. Toxicity assays with Artemia salina confirmed the safety of the extracts, showing no lethal effects at the tested concentrations. These findings reinforce the efficacy and safety of formulations obtained through green methods for cosmetic applications. In conclusion, Lippia thymoides demonstrates remarkable potential as a source of bioactive compounds with antioxidant, antimicrobial, and photoprotective properties, offering a sustainable and efficient alternative for the development of innovative cosmetic formulations.