Effect of extraction solvent on antiradical activity of the obtained propolis extracts

Total phenolic, flavonoid and mineral contents and antiradical activity are usually used as a measure of propolis extract quality. The purpose of this study was to compare the quality of propolis extracts obtained with different solvents such as water, ethanolic solutions (30, 70, 95%, v/v in water) and edible vegetable oils (canola and soybean). LC-MS was used to identify constituents of the extracts. Antiradical activity was assayed using chemiluminescence from the luminol/hemin/H2O2/CTAB system and the DPPH test. Both antiradical assays were strongly correlated (r = -0.97). Principal Component Analysis indicated positive correlations for phenolics, flavonoid levels and antiradical activity showing that all phenolic compounds are important for the scavenging activity of Brazilian propolis. The extract obtained with ethanol 30% v/v had the highest antiradical activity mainly due to its high content of dicaffeoylquinic acids.