Isolation and characterization of compounds in ethanolic extract of Albizia coriaria (Welw ex. Oliver) leaves: a further evidence of its ethnomedicinal diversity

Background Albizia coriaria Welw ex. Oliver ( A. coriaria ) is one of the treasured medicinal plants in Africa. In continuity of our study verifying the claim of using its leaves for managing bacterial diseases and oxidative stress-mediated complications in Ugandan traditional phytomedicine, we characterized its most active (ethanolic) extract using ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thin layer chromatography, column chromatography and gas chromatography–mass spectrometry. Results UV–Vis absorption peaks occurred between 338 and 664 nm, which indicated the presence of alkaloids, flavonoids and terpenoids. FTIR spectrum of the extract indicated the presence of O–H, C=O and aromatic–C=C which confirmed the presence of alcohols, carboxylic acids and aromatics in the extract. Four known bioactive triterpenoids: lupeol ( 1 ), lupenone ( 2 ), betulinic acid ( 3 ), betulin ( 4 ) along with an aromatic alcohol: benzyl alcohol ( 5 ) were tentatively identified in different fractions of A. coriaria ethanolic leaf extract. Compound 4 was identified for the first time in this species. Conclusions All the compounds identified in the fractions of the A. coriaria ethanolic leaf extract have reported pharmacological activities, including antioxidant and antibacterial activities. This supports the traditional use of A. coriaria leaves in the management of oxidative stress-mediated conditions and bacterial diseases in Uganda.