Avaliação in vitro do potencial antimicrobiano do extrato hidroalcoólico de geoprópolis de melipona quadrifasciata quadrifasciata frente à bactérias da microbiota cutânea

Abstract

The bee diversity conservation is a sustainability issue, having ecological, economical and food safety importance, because they are the main pollinators to the angiosperm reproduction. The stingless bees, or meliponines, are the exclusive geopropolis producers, a mix of mud or soil with salivary secretions, wax and plants exudates. This bee product has been arousing interest of scientific community due to its biological properties. In view of the spread of antibiotic resistant bacteria and the global health problem that it is becoming, alternative therapies with natural products are emerging, characterized by its effectiveness, low cost, the minimum risks against adverse effects and antimicrobial resistance. Thereby, this paper aimed to physico-chemically characterize Melipona quadrifasciata quadrifasciata raw geopropolis, and avaluate the antimicrobial potential of hydroalcoholic geopropolis extract against Cutibacterium acnes and Staphylococcus epidermidis, bacteria that are protagonists of the skin microbiota. For the physico-chemical characterizations, ethanol soluble solids, ash and moisture content analysis were performed. For the evaluation of the antimicrobial activity of geopropolis extract, the methodology used was disk diffusion method. The extract was tested at its initial concentration and at 0,05%, 0,1%, 0,15%, 0,5% e 1,0% concentrations. A moisturizing body lotion based on 1,5% of geopropolis extract was also formulated and its antimicrobial activity against the two same bacteria was evaluated. The results of ethanol soluble solids were above 35%, in compliance with Apis mellifera propolis Brazilian legislation. Moisture and ash content presented medium values of 0,74 ± 0,05% and 48,72 ± 17,60, respectively. The first was within the legislation, which accepts a maximum of 8% for moisture content. On the other hand, the ash content presented values above the recommended, because, according to the legislation, the values must not exceed 5%. It was noted the need to update existing legislation to define a stingless bees geopropolis specific identity and quality. Regarding the antimicrobial potential study, geopropolis extract at the initial concentration of 10%, at 1,0% concentration, and used in the moisturizing lotion, were able to effectively inhibit C. acnes, forming inhibition halos larger than 7,5 mm. S. epidermidis demonstrated to be inhibited by alcohol, and geopropolis appeared as an adjuvant in this inhibition. Yet, S. epidermidis did not presented microbial growth when tested with the cosmetic. It was concluded that geopropolis has significant antimicrobial potential against C. acnes, in addition to being a bee product that still has potential to be explored.