Volatile Composition of Brazilian Stingless Bee Propolis

Stingless bees, or meliponines, are essential pollinators in Brazil, with over 300 described species. These bees produce propolis or geopropolis (characterized by the incorporation of mineral material and clay) used to protect their nests. This product has aroused increasing scientific interest due to its therapeutic potential, including antimicrobial and anti-inflammatory activities. However, there is still limited knowledge about its volatile composition, which can vary according to the bee species and the botanical origin of the resins, influencing their biological and aromatic properties. The purpose of this study was to characterize the volatile composition of (geo)propolis produced by different species of native stingless bees from the Southeastern region of Brazil (São Paulo and Minas Gerais) and to detect if this composition is influenced by the species or by the region. The samples were analyzed by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The results indicated that, despite some variations, the chemical profile for each species was mostly constant between regions. In São Paulo, about 25% of the features varied between species, whereas in Minas Gerais, only 5% showed significant differences, although one species (Melipona quadrifasciata) presented a very constant composition. Although the local vegetation determines the supply of resins for these bees, differences in the chemical composition of propolis are a result of a species' choice of plant species.