Chemical composition, antinociceptive and free radical-scavenging activities of geopropolis from Melipona subnitida Ducke (Hymenoptera: Apidae: Meliponini)

Abstract

Like many stingless bee species, Melipona subnitida Ducke uses geopropolis (a mixture of wax, plant resins, pollen grains and mud) for sealing small crevices in their nest cavities, in order to avoid the entry of air, and for defense against pathogenic microorganisms. The aim of this study was to evaluate the antinociceptive and free radical-scavenging activities of ethanolic extracts of six geopropolis samples from M. subnitida and the phenolic fractions obtained by C18-SPE extraction. The in vivo antinociceptive activity was analyzed on abdominal constriction induced by acetic acid in mice and in vitro free radical-scavenging activities by DPPH and ABTS assays. Additionally we analyzed the chemical composition of the phenolic fractions by HPLC-DAD. The six samples of geopropolis showed variations in the total phenolic content over the period, but not in the chemical profile observed by HPLC-DAD. Geopropolis is a rich source of bioactive compounds as phenolics 6-O-p-coumaroyl-D-alactopyranose, 6-O-cinnamoyl-1-Op-coumaroyl-β-D-glucopyranose, 7-O-methyl naringenin, 7-O-methyl aromadendrin, 7,4’-di-O-methyl aromadendrin, 4’-O-methyl kaempferol, 3-O-methyl quercetin, 5-O-methyl aromadendrin and 5-O-methyl kaempferol with potential antioxidant and antinociceptive activities. The antioxidant activity is related to the total phenolic content.