Phenolic composition of a propolis type from Ceará-Brazil: study of different extraction techniques

Propolis is a complex mixture composed by secretions of bees and material collected by them from different part of plants, and its chemical composition varies according the habitat and season. In this study, ethanolic extraction of a propolis (EEP) type from Ceará-Brazil was performed using soxhlet, under reflux extraction and maceration at room temperature as extraction techniques. It was determinated the yield, total phenolic concentration, chromatography profile and antioxidant activity in all extracts obtained. According to the results, the extracts obtained from maceration showed the highest yields, 40.65 ± 0.21% when compared with obtained from soxhlet, 36.45 ± 1.39%, and under reflux, 24.03 ± 0.60%. Results revealed that the different extraction techniques did not affect the phenolic composition of EEP. It was obtained 41.33 ± 1.68; 41.65 ± 2.41 and 41.38 ± 4.32 mg/g of total phenolics from EEP by maceration, soxhlet and under reflux extraction, respectively. The EEP after liquid-liquid partition with hexane revealed a greater apolar composition (aprox. 80%) which explains the lower phenolic content. Besides this, liquid chromatography (HPLC) results showed the presence of p-coumaric, ferulic and trans-cinnamic acids as phenolic composition. Propolis extract exhibited 17% antiradical action against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at 20 ppm for all extracts. Based on this study, although the low antioxidant activity, it was possible to identify the main phenolic composition of a propolis from Ceará and tests to determinate other chemical compounds may be conducted in order to evaluate its potential.