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Two Brazilian propolis was characterized by UPLC-QTOF/MS2.Surprisingly, piperidinic alkaloids were identified among the constituents.The cytotoxic effect of propolis extracts on melanoma cells was evaluated.Both extracts exert their cytotoxicity by inducing apoptosis.The present study characterized propolis extracts produced by Scaptotrigona bipunctata (Tubuna) and Melipona quadrifasciata (Mandaçaia) by LC–MS/MS; their cytotoxicity as well as the mechanism of action in a melanoma cellular model were also assessed. The chemical characterization performed by UPLC-ESI-QTOF/MS2 analysis revealed uncommon presence of piperidinic alkaloids in Tubuna's propolis extract together with C-glycopyranoside flavonoids. Mandaçaia's propolis collected in the same area rather presented terpenoids and flavonoids. Regarding the mechanism of cytotoxicity, propolis extracts increased the accumulation of reactive oxygen species (ROS), reduced the potential of mitochondrial membrane, induced a decrease in the proteins Bcl-2 and AKT-3 levels, and decreased melanoma cells' migration and invasion. Both propolis extracts induced apoptosis while only Mandaçaia's propolis extract induced cell cycle arrest in G2/M.