Caracterização química e atividades biológicas da geoprópolis produzida por Melipona rufiventris

Abstract

Natural products are used by humans in cure and to prevent diseases since immemorial times. Among the natural products most used in the world, we can mention geopropolis that is characterized as resinous substances produced at any time of the year by Brazilian native bees from a mix of materials collected from various parts of the plants which they add wax, pollen 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 stingless beekeepers. Due to the scarcity of existing and published researches with the geopropolis produced by Melipona rufiventris, this work is justified by the need to evaluate the chemical profile and the antimicrobial, antioxidant and anti-inflammatory properties of this product in order to elucidate possible future uses for the product. Furthermore, projects related to the bioprospecting of bees’ products can reinforce the meliponiculture and maintenance of native bees. For the evaluation of the chemical composition and biological activities of the geopropolis, the sample was collected in the Cabo Verde-MG region and an ethanolic extract was produced. Chemical analysis were performed to explore the composition of the extract, using spectrophotometry and thin layer chromatography, the quantitative determination of phenolic compounds a chromatographic profile by HPLC. To determine the biological activities, the sample was submitted tested in a Galeria mellonella model to evaluate its systemic toxicity. Subsequently, in vitro assays were performed to determine the antimicrobial and synergic activities, evaluating the minimum inhibitory concentrations, minimum microbicidal concentrations and the interaction between the extract and the commercial antimicrobial; antioxidant by DPPH and superoxide free radical scavenging methods, as well as peroxyl radical absorption capacity; cell viability determined by MTS; and anti-inflammatory. The results indicate the possible presence of phenolic compounds, including flavonoids and terpenes in the sample. The analysis by HPLC shows that the extract has a complex composition, but it was not possible to accurately identify the main chemicals present in it. The antimicrobial activity test showed that the extract has a higher activity against Gram-positive bacteria, as well as a considerable activity against multiresistant bacteria isolated from complex wounds. The EEGP also showed synergistic activity in conjunction with the commercial antimicrobials amoxicillin and sulfamethoxazole + trimethoprim. For analyzes of anti-inflammatory activity, the extract inhibited NF-kB activation and TNF-α release at safe concentrations. Despite these biological activities, EEGP showed no antiproliferative activity by MTS method. More refined analyzes are still needed to clarify the chemical composition of the extract, but it is concluded that is has phenolic and terpene compounds that may be molecules responsible for the biological activities.