Evaluation of Methanol Stem-bark Extract of Ximenia americana Linn (Olacaceae) for Phytoconstituents and Gastroprotection in Rats

Background: The Hausa/Fulanis in northern Nigeria and other tribal communities use different parts of Ximenia americana for several ailments such as malaria, infectious diseases, fever, and constipation, with the stem bark used for gastric ulcers. The plant is one of eight species of the Olacaceae family that grows mostly in tropical countries and has common names such as “sour” or “monkey plum”, known in the Northern part of Nigeria as “Tsada”, in the eastern part as ‘Anya Nwona’, and in the western part as ‘Igo’. The study was an attempt to validate the purported ethnomedicinal use of the stem-bark of the plant in gastric ulcer. Objective: This study investigated the phytochemical constituents of stem-bark extract and its gastro-protective potential. Methods: Lorke’s acute toxicity test for oral median lethal dose (LD50) estimation and preliminary phytochemical screening were conducted. The antiulcer effect was evaluated in indomethacin- and ethanol-induced ulcer models using Wistar rats in two sets of 5 groups of 5 each, starved for 24 hrs. Oral body-weight normal saline(1ml/kg), standard-drug (100mg/kg cimetidine or misoprostol) for the respective models, and extract-doses (250, 500 and 1000mg/kg) administered for 30 minutes before body-weight 6h indomethacin ulceration or 1h absolute ethanol (1ml) were used. Lesions and larger-diameter (≥ 3mm) ulcer spots in isolated stomachs of euthanized rats were counted.  Results: The extract contained alkaloids, anthraquinones, carbohydrates, flavonoids, saponins, steroidal glycosides, tannins, and terpenoids, and significantly (p≤0.05) and dose-dependently reduced the mean number of ulcer spots, with effects comparable to those of cimetidine and misoprostol. Reduction was significant only for 500 and 1000mg/kg extract-doses. Nine severe ulcer spots in normal-control rats against 3 in 250 and 500mg/kg groups and none in the 1000mg/kg or cimetidine group occurred with indomethacin ulcerogen. Severe ulcer spots were not found with ethanol-ulcerogen even in normal control rats.  Conclusion: This study, therefore, supported the folkloric use of Ximenia americana stembark in ulcer management.