Endopleura uchi: a medicinal plant with antidiabetic potential

Endopleura uchi is an Amazonian tree and its bark is used as tea against arthritis, cholesterol, diarrhea and cancer. In spite of its large use, the antidiabetic, anti-cholinesterase, antioxidant and cytotoxic against Caco-2 of this species have not been assessed before and its chemical composition is less studied. In this work two different extracts (infusion and hydroethanolic) were studied concerning phenolic composition and biological potential. Five compounds were determined by HPLC-DAD, being bergenin the major one. In general way, infusion presents a greater richness in these metabolites. The antioxidant, acetylcholinesterase, butyrylcholinesterase, α-glucosidase and antibacterial activities were checked by in vitro assays. A dose-dependent response was noticed against DPPH·, superoxide and nitric oxide radicals, acetylcholinesterase, butyrylcholinesterase and in the α-glucosidase inhibitory assay. In the latter case, hydroethanolic extract (IC ₅₀= 2.2 µg/mL) and infusion (IC ₅₀= 2.4 µg/mL) showed remarkable activity as compared to the control acarbose (IC ₅₀= 284 µg/mL). Antibacterial capacity of both extracts was investigated against Gram-positive and Gram-negative bacteria, being more effective against the first one. The concentrations of extracts tested here showed no toxicity on intestinal (Caco-2) cells. These results suggest that the extracts of E. uchi may be interesting for incorporating in pharmaceutical preparations, since it may suppress hyperglycaemia and inhibit cholinesterases, or can be utilized as food additive due to its antioxidant and antibacterial activities.

Acknowledgements: The authors are grateful to the financial support from CICS (PEst-OE/SAU/UI0709/2014). Luís R. Silva (SFRH/BPD/105263/2014) Marco G. Alves (SFRH/BPD/80451/2011) are indebted to FCT for the grants.