Physicochemical Profile of Non-polar Extracts of Colombian Propolis (Npcs) and Their Correlation With the Antimicrobial Activity of Pathogenic Strains

Abstract

Honeybees collect multiple types of propolis with high concentrations of bioactive compounds with notorious antimicrobial activity against gram-positive and gram-negative bacteria, undesirable microorganisms in food products. Propolis is produced by collecting and transforming plant exudates around hives. Their composition and action against pathogenic microorganisms vary according to the hive structure and the plant's chemical composition. In the literature, there is a lack of information on the Colombian propolis action against pathogens, and there is no information about the chemical profile of the compounds in these samples. Therefore, to identify propolis's chemical profile and correlate the metabolites with the antimicrobial action, it is necessary to perform a metabolomic analysis that integrates spectroscopic techniques and bioassays. Techniques such as GC-FID, NMR, and U-HPLC were used to obtain the profile and concentration of low molecular weight metabolites, amino acids, fatty acids, and polyphenols. Then, the extracts were analysed by minimum inhibitory concentration (MIC) tests to elucidate the bactericidal power of the extracts. It was concluded that the ecosystem and botanical species are the main characteristics that allow the discrimination of propolis. Additionally, it was seen that the bioactivity against pathogens was due to a synergistic effect between various metabolites, which have variations in their chemical structure, mainly in molecular weight and functional groups. Additionally, it was seen that the ecosystem has a more significant influence on the propolis composition compared to the bee species that collect the exudates.