Abstract

Uapaca guineensis Mull. Arg. (Euphorbiaceae) commonly called false mahogany and “Ewe akun” in the western part of Nigeria grows in humid localities, mixed evergreen forest and sea-level up to 1100 m altitude. The study was designed to isolate Betulinic acid (3?-hydroxylup-20-(29)-en-28-oic acid) which is a naturally occurring pentacyclic triterpenoid that exhibited antibacterial, antimalarial, anti-inflammatory, anthelmintic and antioxidant properties from the stem bark and root of Uapaca guineensis. The air-dried and pulverized stem bark and root of U. guineensis (0.5 kg each) were separately extracted with aqueous ethanol (80%) for 72 hour at room temperature, filtered, concentrated on rotatory evaporator at 37 oC and then stored in a desiccator. The ethanol extracts of the stem bark was partitioned successively with n-hexane, dichloromethane and methanol, while ethanol extract of the root was chromatographed directly. The dichloromethane and methanol extracts of the stem bark was also chromatographed. These results in the formation of whitish powder that are UV inactive and also gave single spot each with cerium sulphate. They are coded as DBG-D13 (25.0 mg), MBG-Q3 (6.1 mg) and ERG-E7 (20.0 mg) for dichloromethane, Methanol and Ethanol extracts respectively. The structure was unequivocally established by 1HNMR, 13CNMR, 2D-NMR, IR, UV and MS spectra analysis as well as by comparison of the spectra data with previously reported values. The dichloromethane, methanol and the ethanol extracts all yielded betulinic acid in substantial quantity. The isolated compound is a confirmation to existing information and an addition to the library of organic compounds.

Keywords: Uapaca guineensis, Euphorbiaceae, and Betulinic acid