Identification of Betulinic Acid and Trimethoxyellagic Acid as the Antidiabetic Compounds in Anogeissus leiocarpus Stem Bark Purified Extract

Abstract

Objectives: The study aimed to identify the antidiabetic compounds purified from stem bark of Anogeissus leiocarpus and propose the mechanisms of action. Design: Anogeissus leiocarpus stem bark was purified through ethyl acetate and n-hexane with minor exceptions. For very clear separation, cold acetone was added to trigger the precipitation. The precipitate was dissolved with a mixture of DCM:methanol (9:1), adsorbed it to silica gel (5 g), evaporated to free flowing powder and fractionated it over silica gel (50 g) to realize 40 fractions. The gummy fractions were ignored. The light brown powder which possessed antidiabetic effect was selected for Nuclear Magnetic Resonance for structural elucidation.     Nuclear Magnetic Resonance (NMR) and Determination of Structure of Purified Compound: After column chromatography and TLC processes, along with the cold acetone, to the point of crystallization, the purified compounds, the light brown powder, were presented to NMR (Bruker Avance III, Spectrometer frequency 400 MHz; solvents DMSO-do, CDCl3, Acetone-d6. Institute of Chemistry, Strathclyde University Glasgow UK.) for determination of compound structures and analyses. Results: The NMR spectra and analyses revealed the existence of Betulinic acid and Trimethoxyellagic acid. Conclusion: We show that Betulinic acid and Trimethoxyellagic acid are potent antidiabetic compounds in the stem bark extract of A. leiocarpus. Keywords: Anogeissus leiocarpus, Betulinic Acid, Trimethoxyellagic Acid, Antidiabetic agent