Caracterización química y actividad antioxidante de tres muestras de propóleos ecuatorianos

Abstract

Propolis is a natural resinous-looking product, which is manufactured by Apis mellifera bees from the selective collection of vegetable exuded, which are mixed with salivary secretions and beeswax. Its organoleptic characteristics, chemical composition and biological activity depend directly on the surrounding flora, geographical area and even the harvesting season. This research aimed to analyze the chemical composition of propolis samples from the provinces of Imbabura, Pichincha and Los Ríos, through chromatographic and spectroscopic methods, to establish the existing relationship with their possible antioxidant activity. The propolis samples were collected in the honey and hive apiary "Tabacundo", subsequently, they underwent extraction by dynamic maceration, using methanol as solvent. The extracts were taken to a rotoevaporator and concentrated dryly, thus obtaining the dry extracts of propolis (ESP). The yield achieved for each of the propolis samples turned out to be good, with values close to 50%. ESPs were stored under appropriate conditions for further study. Preliminary analysis of the chemical composition of ESP was performed using phytochemical screening, seeking the identification of phenolic and flavonoid compounds, followed by a thin layer chromatography (CCD) evaluation. Qualitative trials suggested the presence, in all three samples, of phenolic compounds in general and flavonoids, as well as showing antioxidant capacity. In addition, similar chromatographic behavior is suggested for all three samples and the existence of terpenic metabolites. Subsequently, total phenols were quantified using the Folin-Ciocalteu and flavonoid method using the colorimetric method of aluminium trichloride. The sample from Pichincha (PE-20) had the highest number of phenolic compounds (EAG) and flavonoids (EQ), followed by the sample of Imbabura (PE-22) and Los Ríos (PE-21), respectively.