Desenvolvimento e caracterização de filmes poliméricos contendo extrato de Zanthoxylum rhoifolium Lam com ação antibacteriana

Abstract

In recent years, bacterial resistance has intensified, becoming a global challenge and driving the search for new therapeutic strategies. In this scenario, polymeric films have stood out as controlled-release systems in the pharmaceutical, biomedical and industrial fields, due to their ability to incorporate diverse compounds. Among the applied biopolymers, cellulose acetate (ACT), derived from cellulose, is biodegradable, non-toxic and biocompatible. At the same time, interest has grown in plant raw materials rich in secondary metabolites, which provide relevant biological activities, such as the antimicrobial action of Zanthoxylum rhoifolium Lam., a species traditionally used in Brazil, whose extract has been evaluated regarding its biological properties and potential applications. The aim of this study was to develop and characterize ACT films with different concentrations of ethanolic extract of Zanthoxylum rhoifolium Lam., and to verify their antibacterial activity. The extract was obtained by maceration of the leaves, concentrated and analyzed regarding its antibacterial action. The films were produced by the casting method and characterized with regard to hemolytic potential, bending resistance, swelling, wettability, optical and scanning electron microscopy, roughness, infrared spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry. Antibacterial activity was evaluated by the disk agar diffusion method. The extract showed antimicrobial efficacy, proven by the minimum inhibitory concentration of 500 μg/mL and 1000 μg/mL. The films showed uniformity, flexibility and hemocompatibility. Mechanical tests indicated bending resistance, while swelling demonstrated water absorption, confirmed by the hydrophilic profile in the contact angle. Microscopy revealed a homogeneous and porous structure. FTIR analysis suggested incorporation of the extract, with an aliphatic C–H band in the films containing extract and absence in pure ACT, suggesting polymer–extract interaction. Thermal analyses showed matrix stability and absence of incompatibilities, except at higher extract concentrations. X-ray diffraction indicated reduced crystallinity and increased amorphous halo. The plate activity demonstrated inhibitory effect against the Gram-positive bacterium Staphylococcus aureus. Therefore, the data reinforce the potential of the films as an alternative for release systems with antibacterial action.