Characterization of propolis extracts from the Tolima region in Colombia: a study of their composition, antimicrobial activity, and cytotoxicity.

[BACKGROUND] Propolis is a complex resinous material collected by bees from plant sources and known for its rich content in bioactive phenolic compounds, including flavonoids and aromatic acids. Its chemical composition and biological activity are highly influenced by the botanical and environmental conditions surrounding the beehives. In Colombia, limited studies have addressed the chemical diversity and therapeutic potential of propolis from regions with high altitudinal variation such as Tolima.

[RESULTS] In this study, three propolis ethanolic extracts (PrEE1, PrEE2, PrEE3) were obtained from hives located at different altitudes in Tolima, Colombia (1250, 1100, and 900 m above sea level (a.s.l.), respectively). Samples were analyzed for total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity (DPPH, ABTS, FRAP), antimicrobial activity (disk diffusion and minimum inhibitory concentration), and cytotoxicity in A549, WI-38 and NIH-3 T3 cell lines. Ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC-MS) analysis revealed a distinct phytochemical profile for each extract. PrEE1 had the highest TPC (130.2 g GAE kg) and TFC (6.70 g QE kg), and strong antioxidant activity with DPPH scavenging of 89.2%. It also exhibited potent antimicrobial activity against Staphylococcus aureus and Candida albicans, and selective cytotoxicity toward A549 lung cancer cells. In contrast, PrEE3 had lower phenolic content but contained unique polyprenylated benzophenones.

[CONCLUSION] The results indicate that altitude significantly influences the chemical and biological properties of Colombian propolis. Propolis from higher altitudes, such as PrEE1, is a promising natural source of multifunctional bioactive compounds with antioxidant, antimicrobial, and anticancer potential for pharmaceutical and nutraceutical applications. © 2025 Society of Chemical Industry.