Proteomic characterization of medicinal plants used in the treatment of diabetes.

Several plants have been studied for their medicinal properties, especially concerning the management of chronic diseases, such as diabetes, aiming at a more accessible form of treatment. In this context, the aim of this study was to characterize plant proteins used in folk medicine as hypoglycemic agents for the treatment of diabetes, namely "abajerú" (Chrysobalanus icaco) and "cow's paw" (Bauhinia forficata and Bauhinia variegata). The species were differentiated by proteome characterization. Proteins were in-solution digested using trypsin by the filter-assisted sample preparation (FASP) method. Peptides were then analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) for protein characterization. In total, 131 proteins were identified. The main biological functions of these proteins were cellular respiration, transport, metabolism and photosynthesis. Insulin-like proteins were not detected, but proteins involved in controlling glucose levels were. The results are of value in the proteomic characterization of phytotherapeutic plants, and may serve as baseline for the assessed species in Brazil, where a lack of knowledge in this regard is observed.