PHYTOCHEMICAL EVIDENCE FOR THE BOTANICAL ORIGIN OF TROPICAL PROPOLIS FROM VENEZUELA

The phenolic compounds present in 38 propolis samples produced in tropical Venezuela by imported Apis mellifera and five indigenous species of stingless bees, and seven propolis samples from different temperate regions were analysed by HPLC. The different tropical propolis generally showed a single phenolic profile characterized by the occurrence of polyprenylated benzophenones as major components. Flavonoids were present in only a few samples, and in each case they were found to be lipophilic methylated 6-oxygenated flavones (eupatorin, hispidulin, 5-hydroxy-6,7,3',4'-tetramethoxyflavone, etc.). Generally, no correlations between the composition of tropical propolis and the place of collection or the bee species were found. However, propolis from temperate areas contained flavonoids (with an unsubstituted ring B) as the main phenolic components (pinobanksin, pinobanksin 3-acetate, pinocembrin, chrysin, galangin and tectochrysin). These analyses confirmed that the source of the phenolics found in propolis produced in temperate regions was different Populus species of section Aigeiros (Salicaceae). The resins exuded by the flowers of Clusia minor and C. major (Guttiferae) contained the polyprenylated benzophenones found in the majority of the propolis studied, suggesting that this is the main source for propolis in tropical Venezuela.