Blendas de amido de gengibre/ poli (álcool vinílico) com emulsão de óleo essencial de breu branco (Protium Heptaphyllum) para potencial aplicação antimicrobiana

Abstract

Research on new biomaterials for the treatment of diseases has aroused great interest due to its social relevance. In this context, the study of polymer blends based on ginger starch and poly(vinyl alcohol) emerges as a promising approach. Ginger starch is an abundant and easily obtainable resource, while poly(vinyl alcohol) is a biocompatible, inexpensive and non-toxic polymer, although it has limitations in its mechanical properties. The combination of these materials can result in a biomaterial with characteristics suitable for the treatment of inflammatory diseases. In addition, the incorporation of breu branco essential oil emulsion into the polymer matrices can confer additional properties, making the material even more efficient. However, there is still no conclusive data on this oil's anti-inflammatory and healing potential. In this study, blends of ginger starch and poly(vinyl alcohol) containing different concentrations of branco breu oil emulsion (0.1%, 0.5%, 1% and 5% v/v) were investigated for the first time. Analyses of the branco breu essential oil emulsion, including zeta potential, gas chromatography and in vitro assays were performed to evaluate the antibacterial activity against S. aureus and E. coli, in addition to the antifungal action against C. albicans. The results indicated that the emulsions presented a chemical composition characteristic of the oil and demonstrated the ability to inhibit the growth of S. aureus and E. coli strains. The polymeric compositions were developed by the casting method and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA/DTG/DSC), mechanical tensile test, swelling evaluation and determination of moisture content. The micrographs obtained by SEM revealed that the blends without emulsion presented a dense surface, while those containing branco breu oil exhibited a heterogeneous surface. The fluid absorption tests showed that the ginger starch (GS) film presented the highest swelling index, reaching 158% ± 0.24 after 24 h. The BP 0.5% composition demonstrated the highest tensile strength, with a value of 35 MPa ± 1.26 and the highest elastic modulus 143.2 ± 3.36. In the differential scanning calorimetry (DSC) analysis, the addition of the emulsion did not significantly alter the thermal degradation profile, maintaining the highest degradation peak of the BP 0.5% composition at 306 °C. Furthermore, the emulsion influenced the moisture content of the films, with the BP 0.5% blend presenting a moisture value of 10% ± 0.06, being the least moist among the samples analyzed. Overall, the results indicate that the developed compositions represent a viable alternative for possible antibacterial and antimicrobial application, combining improved mechanical properties.