Filmes de quitosana com extrato etanólico das folhas de Plinia cauliflora: propriedades físico-químicas e atividades antimicrobiana, antioxidante e antiinflamatória

Abstract

Biopolymers such as chitosan have gained prominence in contemporary research due to their physicochemical characteristics and formulation possibilities. With a wide range of uses, chitosan films attract attention due to their biological potential and the possibility of developing controlled release systems. On the other hand, Plinia cauliflora, or jabuticaba, is a native plant, recognized in the literature for its antiinflammatory, antioxidant and antimicrobial benefits. Therefore, this study sought to develop chitosan films incorporated with ethanolic extract of Plinia cauliflora leaves and evaluate their antimicrobial, anti-inflammatory and antioxidant properties. The leaves of Plinia cauliflora were first extracted and then assayed for phenols, tannins and flavonoids. The assay found 310.42 ± 8.75 µg/mg to tannic acid equivalent of total phenols, 108.56 ± 0.39 µg/mg to tannic acid equivalent of tannins and 36.80 ± 3.44 µg/mg to rutin equivalent of flavonoids. In the cell viability, anti-inflammatory, antioxidant and antimicrobial in vitro tests, the extract proved to be effective. Using the solvent evaporation technique, chitosan films were formulated with the addition of the ethanolic extract of Plinia cauliflora leaves at concentrations of 5% (EEPC5%), 2.5% (EEPC2.5%) and 1% (EEPC1%). The film precursor solutions were characterized by means of rheological measurements and parameters such as zeta potential, hydrodynamic diameter and electrical conductivity, where it was possible to observe that EEPC5% has a better interaction between the components of the formulation and the extract. In the release test, the films showed the functioning of the controlled release system and it was also possible to verify that the EEPC5% film had a higher release percentage. Other physicochemicals parameters of the dried films were evaluated by measuring thickness, average weight, moisture content, degree of swelling, solubility and scanning electron microscopy. In order to understand the intermolecular interactions in the dried films, thermal analysis, vibrational spectroscopy in the infrared region and dynamic mechanical analysis in axial and rotational mode were also carried out. In the cell viability test, the films were not toxic to intraperitoneal macrophage strains from BALB/c mice and to L929 fibroblasts. In the anti-inflammatory activity test, the EEPC5% film proved to be more effective, reducing the production of nitric oxide and interleukin 6 (IL-6). While the EEPC2.5% and EEPC1% films showeds only a slight reduction in IL-6. The films proved to be excellent antioxidants, especially EEPC5%, with significant results in the DPPH free radical scavenging method and in the phosphomolybdenum complex reduction method. Evaluating their antimicrobial effect, the films were able to inhibit the growth of C. albicans, S. aureus and S. epidermidis by between 80 and 100%. Therefore, we can consider that the integration between the components of the formulation was viable, capable of producing malleable and flexible films with significant antioxidant, anti-inflammatory and antimicrobial activity in vitro, with potential use as a dressing for skin lesions