Composição química, potencial antioxidante e antimicrobiano (in vitro) de extratos de geoprópolis de abelhas sem ferrão da Amazônia

Abstract

The Amazon region presents a growing development of meliponiculture, the rational breeding of stingless bees. However, an essential product of this activity, geopropolis (a material made from resinous substances collected from plants to which bees add salivary secretions, wax, pollen, and earth), still has little value on the market due to the lack of information about its chemical composition and biological activities. The objective of this work is to study the geopropolis of stingless bees uruçu amarela (Melipona flavolineata), uruçu boca de renda (Melipona seminigra pernigra), and uruçu cinzenta (Melipona fasciculata), from the city of Terra Alta, located in the northeast of the state of Pará, regarding its chemical and mineral composition, determination of bioactive compounds, evaluation of antioxidant and antimicrobial properties and determination of the chromatographic profile (volatile compounds) of geopropolis ethanolic extracts obtained by agitation and sonication. The extracts from the optimal condition showed significant levels of total phenolic compounds, ranging from 5491.1 ± 446.33 to 13019.19 ± 186.56 mg EAG/100g, as well as the content of total flavonoids, which was between 190.31 ± 2.61 and 2498.02 ± 78.24 mg QE/100g. Regarding antioxidant activity, the sample with the best performance was yellow uruçu, which presented results of 1537.66 ± 19.52 μmol trolox eq./g, 1773.56 ± 6.52 μmol trolox eq./g and 7074, 41 ± 215.73 μmol ferrous sulfate eq./g, in the respective DPPH, ABTS and FRAP tests. Samples from uruçu Boca de renda and uruçu content presented antimicrobial action, with a minimum inhibitory concentration of 0.5 and 2 mg/mL, respectively. The analysis of volatile compounds demonstrated distinct chemical profiles between the samples since only 3 of the identified compounds (less than 4% of the total) were standard in all analyzed samples, suggesting that the geopropolis of the three species are made from different resin sources, despite the hives being located in the same environment. This exploratory research contributes essential information to the knowledge of the activities exhibited by the geopropolis produced in the Amazon region, helping in the progression of studies on stingless bees.