Propolis is a resin collected by bees from several plant sources and used by humans for centuries. Its commercial use is usually based on alcoholic extracts, which is a drawback for some applications. Conversely, oil extracts are non-toxic and capable of extracting and dissolving a wide range of less polar compounds. As previous studies showed that oil extracts presented bioactivity similar to ethanolic extracts, a reproducible method for the extraction of green Brazilian propolis was developed and patented. The antimicrobial and cytotoxic activities of the ethanolic and oil extracts of green propolis were compared as well as their ultra-high-performance liquid chromatography with high-resolution mass spectrometry (UHPLC-HRMS) profiles, with similar results. A method was developed to recover propolis bioactive compounds from the oily matrix in order to allow its qualitative and quantitative quality control, according to parameters determined by the Brazilian Ministry of Agriculture, and is presented herein for the first time. The total flavonoid and phenolic contents, antioxidant activity and dry mass are comparable to the ethanolic extract. Therefore, OEP can be recommended for the diverse food supplements and cosmetic products that currently use the ethanolic extract of propolis, without the drawbacks of the presence of alcohol in these formulations.
Oliveira et al. (Wed,) studied this question.