Chemical composition and antioxidant activity of geopropolis produced by Melipona fasciculata (Meliponinae) in flooded fields and cerrado areas of Maranhão State, northeastern Brazil

Abstract

ABSTRACT Geopropolis, a mixture of plant resin, wax, soil and salivary secretion, is produced by the stingless bee Melipona fasciculata. This aim of this study was to investigate the chemical composition and antioxidant activity of geopropolis collected from beehives in two phytogeographical regions, flooded fields and cerrado, in the municipalities of Palmeirândia and Fernando Falcão, Maranhão State, northeastern Brazil. The geopropolis compounds were identified by gas chromatography-mass spectrometry (GC/MS). Additionally, total phenolic content was determined with the Folin−Ciocalteu reagent and antioxidant activity was evaluated in vitro by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The four geopropolis samples varied in terms of total phenolic content and antioxidant activity and the highest values were observed for geopropolis from Fernando Falcão. Triterpenes such as cycloartane, ursane and oleanane and phenolic acids (protocatechuic acid and gallic acid) were identified in the geopropolis from Palmeirândia, while the phenolic acids, gallic and ellagic acid were the main compounds in geopropolis from Fernando Falcão. The antioxidant property of geopropolis is due to its high total phenolic content and predominance of gallic acid and ellagic acid. The results showed that the plant resources in two phytogeographical regions of Maranhão used by bees for the production of geopropolis contribute to the chemical composition and bioactivity of this product.