Ecuadorian stingless bee (Meliponinae) honey: A chemical and functional profile of an ancient health product

Stingless bee honey samples from west Amazonian Ecuador were studied for their physiochemical, chemical and functional properties. Reducing sugars (44.9 +/- 5.72 g/100 g), water (34.1 +/- 4.34 g/100 g), free acidity(31.8 +/- 4.05 meq/100g), diastase activity (1.60 +/- 0.20u.d./g), hydroxymethylfurfural(15.0 +/- 1.91 mg/kg), electrical conductivity (0.48 +/- 0.06 mS/cm), ash (0.28 +/- 0.4 g/100g), colour (150 mm Pfund) were determined as physicochemical parameters. Melissopalynological analyses were processed evidencing pollen belonging to 14 plant families. Glucose (25.5 +/- 3.41 g/100 g), fructose (25.2 +/- 3.37 g/100 g) and sucrose (3.72 +/- 0.49g/100g) contents were determined by HPLC, evidencing equal concentrations between fructose and glucose. Coumarins and flavonoids were determined by densitometric HPTLC: fraxin and bergamotin (0.065 +/- 0.009; 0.035 +/- 0.005 mu g/g) among coumarins; luteolin (0.045 +/- 0.006 mu g/g), quercitrin (0.020 +/- 0.003 mu g/g), isoramnetin (0.015 +/- 0.002 mu g/g) among flavonoids. Among the vitamin E isomers. evaluated by HPLC, the occurrence of the only P-tocopherol (1.12 +/- 0.15 mu g/g) was noted. All these results were compared with those acquired for two multifloral Apis mellifera honeys. DPPH and beta-carotene bleaching tests were performed, showing interesting values for Ecuadorian honey samples, higher than those shown by multifloral A. mellifera honeys (88.1 +/- 11.1 DPPH inhibition%; 70.8 +/- 8.90 beta-carotene inhibition%). Antibacterial activity, against both Gram positive and Gram negative bacteria, revealed MIC values (10-50 mu g/ml) always lower than those of A. mellifera honeys. Ecuadorian Meliponinae honey samples also showed anti-mutagenic activity assayed with Saccharomyces cerevisiae D7 strain, inhibiting back mutation over the entire range of concentrations. (c) 2008 Elsevier Ltd. All rights reserved.