Caracterização química e determinação da atividade antimicrobiana, antioxidante e antiinflamatória do extrato etanólico de geoprópolis de Melipona quadrifasciata por ensaios in vitro e in vivo em modelo de Galleria mellonella.

Abstract

Geopropolis is a type of propolis produced by species of stingless bees, which consists of a mixture of resin, wax and soil. Although the pharmacological properties of this product have been known since ancient times, studies available in the literature are still scarce. Native stingless bees are of great importance in the maintenance of ecosystems and source of income for local communities of beekeepers. The main objective of this work is to contribute with relevant information about the chemical composition and biological activity of geopropolis produced by the native stingless bee of the species Melipona quadrifasciata, as well as to implement in UNIFAL-MG the model for determining in vivo toxicity and antimicrobial activity using larvae of moths of the species Galleria mellonella. For the evaluation of the chemical composition and biological activities of geopropolis, the sample was collected in the municipality of Morretes-PR and later extracted in ethanol 80% (v/v) to obtain the EEGP. Chemical analyzes were carried out to investigate the composition of the extract, quantitative determination of phenolic compounds and for the determination of biological activities, the sample was submitted to the systemic toxicity test with the G. mellonella model to evaluate the safe concentrations to be used. Subsequently, in vitro assays were carried out to determine the antimicrobial activities, evaluating the minimum inhibitory concentrations, minimum microbicidal concentrations and antioxidant activity by the methods of scavenging free radicals DPPH, ferric reducing potential FRAP and reducing capacity of the oxygen radical ORAC. As a result, it was verified that the content of total phenolic compounds in the EEGP was 23.60±0.22 mg GAE/g of extract. The antioxidant capacity of geopropolis in reducing the DPPH radical was 54.79± 1.64 μmol TEAC/g of extract, the FRAP test showed a result of 2467.33±223.45 μmol SF/g extract, and in the ORAC the EEGP capacity was 0.57±0.03 μmol TEAC/g. The EEGP showed antioxidant capacity of isolated compounds regarding the reduction of the ABTS+ radical online. The antimicrobial activity assay showed that the extract has greater activity against gram-positive bacteria. The extract did not show toxicity in the in vivo model used. In addition to the scientific results that could impact the production of knowledge in the area, we were able to structure the production of G. mellonella larvae, and the implementation of methodologies for the determination of toxicity and antimicrobial activity in vivo, which will thus allow us to envision the possibility of publications in higher impact journals, as well as establishing partnerships with other research groups inside and outside the institution, optimizing public resources, increasing scientific productivity and the institution's visibility.