Evaluación de la composición química y actividad antioxidante de propóleos ecuatorianos de abejas sin aguijón.

Abstract

In this study, the chemical composition and antioxidant capacity of twelve samples of stingless bee propolis collected from different regions of Ecuador were evaluated using chromatographic and spectroscopic methods. Ethanolic extracts were prepared by maceration and analyzed by thin-layer chromatography (TLC) using silica gel 60 GF254 as the stationary phase, with different mobile phases and revealing systems. High-performance liquid chromatography with diode array detection (HPLC-DAD) was also employed for structural characterization. The antioxidant activity of the extracts was determined using the DPPH and FRAP methods, with results expressed as Trolox equivalents (TEAC). The analyses revealed significant differences among the samples, highlighting variability in the content of phenolic compounds and flavonoids, which was reflected in the observed antioxidant capacity. Additionally, the HPLC-DAD analysis results made it possible to group the samples into at least four categories according to their chromatographic behavior and UV spectra, suggesting the presence of triterpenes, flavonols, alkyl resorcinols, and nemorosone. Samples PS4 and PS5 showed the highest antioxidant activity values, suggesting a greater concentration of specialized metabolites. These findings support the potential use of the studied propolis samples as a natural source of bioactive compounds with medicinal and preventive applications related to free radical neutralization and the reduction of oxidative stress.