First Proteome Analysis of Poplar-Type Propolis.

Propolis is a natural mixture of honeybee-released and plant-derived compounds produced by honeybees. Poplar propolis is rich in bioactive polyphenolic compounds, and due to its many health benefits, it is commonly used as a food supplement or functional food ingredient. However, it is the only honeybee product whose proteome hasn't been analyzed. Here, we report a first proteome analysis of poplar-type propolis, a challenging glue-type resinous sample for protein characterization. Raw propolis mixture was precipitated with cold acetone to obtain the protein fraction. Proteins were digested with trypsin, and generated peptides were analyzed on nano-ESI-qTOF SYNAPT G2-Si mass spectrometer (MS) by data-independent acquisition (DIA) and data-dependent acquisition (DDA). Identified peptides and inferred proteins suggest the presence of new bioactive molecules as components of propolis. The poplar-type propolis proteome is composed of a mixture of proteins from the Apis and Populus genera. This is the first-ever report of the proteome of any type of propolis.