Phenolic acids, hydrolyzable tannins and antioxidant activity of geopropolis from the stingless bee Melipona fasciculata Smith
J Agric Food Chem, 2014 Feb 27
Geopropolis is a mixture of plant resins, waxes and soil produced by the stingless bee Melipona fasciculata Smith. This paper describes the antioxidant activity and chemical composition of geopropolis produced by Melipona fasciculata. The total phenolic content determined by the Folin-Ciocalteu reagent was highest in the ethyl acetate fraction and hydroalcoholic extract. Antioxidant activity was assayed by the in vitro DPPH, ABTS and FRAP assays. The hydroalcoholic extract and fractions of geopropolis, except for the hexane fraction, exhibited antioxidant activity against DPPH, ABTS and FRAP. The phenolic compounds were identified by HPLC-DAD-MS based on the evaluation of their UV-vis absorption maxima (λmax) and mass spectral analysis. Eleven compounds belonging to the classes of phenolic acids and hydrolyzable tannins (gallotannins and ellagitannins) were tentatively identified. These compounds are responsible for the antioxidant activity and high phenolic content of geopropolis produced by M. fasciculata.