Propolis from different Brazilian stingless bee species: phenolic composition and antimicrobial activity

Stingless bees (SLB) are insects bread many centuries ago by indigenous people and more than 500 species have already been described. Interest in SLB's propolis has grown as a way to value and preserve native bees, in addition to investigating/prospecting compounds with biological functionality (antimicrobial activity, antioxidant, etc.). The natural active compounds found in propolis come from different plant sources, and consequently, each propolis may show unique biological/pharmacological activity. There is still an important gap about the profile of chemical compounds, biological and pharmacological potential of propolis produced by SLBs. This work aimed to investigate the presence of phenolic and coumaric compounds (HPLC–DAD-FLD) and the antimicrobial activity (microdilution method) of propolis extracts from five different species of SLB reared in different places. The samples from Melipona quadrifasciata (82.05 mgGAEg −1 ) and one from, Frieseomelitta doederleini (56.22 mgGAEg −1 ) showed the highest concentrations of phenolic compounds. It was possible to identify in the propolis samples formononetin, kaempferol, gallic acid and coumarin. Resveratrol was detected in all samples, an unprecedent fact for SLB propolis. Candida albicans was susceptible to all tested extracts, while Escherichia coli was inhibited only by propolis from Melipona quadrifasciata ; Enterococcus faecalis was inhibited by propolis from Plebeia droryana., Melipona quadrifasciata and Frieseomelitta doederleini . It was verified that SLB propolis constitutes a source of different biocompounds, which varies according to the location where the bees are raised, and has mainly antifungal activity, generating possibilities of its use in different biotechnological products. Graphical Abstract