title: Anti-ulcer compound from Voacanga africana with possible histamine H2 receptor blocking activity.
abstract: Voacanga africana is used in Cameroonian ethnomedicine for the treatment of peptic ulcers. We have tested the cytoprotective, anti-secretory and ulcer healing actions of an alkaloid (TN) obtained from the fruit extract. Oral administration of TN (50-100 mg/kg) dose-dependently prevented ulcer formation by HCl/ethanol (36-75%), absolute ethanol (43-75%), HCl-ethanol/indomethacin (58-84%), Pylorus ligation (31-100%), cold restraint stress (68-100%) and histamine (49-100%). The inhibitory effect at 50 and 100 mg/kg against HCl/ethanol was not suppressed by pre-treatment with indomethacin (20 mg/kg, i.p.). TN reduced Shay-ligated gastric acid secretion from 77 mEq/l in the controls to 46 and 25 mEq/l for the 50 and 100 mg/kg doses. Augmented histamine-induced gastric acid secretion was reduced from 84 mEq/l in the controls to 45 and 21 mEq/l for the two doses of TN, with total inhibition of gastric and duodenal ulcers by the 50 mg/kg dose. Healing rate of chronic acetic acid-induced ulcers was 62 and 83%, respectively, for the dose of 50 and 100 mg/kg of TN compared with the controls. TN has gastric anti-secretory effects similar to histamine receptor blockers. Its cytoprotective and ulcer healing properties are related to its ability to strengthen gastric mucosal defenses through enhanced gastric mucus production.
authors.affiliation: Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Cameroon. tanpaul@uycdc.uninet.cm
authors.forename: P V
authors.initials: PV
authors.lastname: Tan
authors.forename: B
authors.initials: B
authors.lastname: Nyasse
mesh_terms: D019342:Acetic Acid; D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002163:Cameroon; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000187:drug effects; D000431:Ethanol; D005638:Fruit; D005750:Gastric Juice / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006851:Hydrochloric Acid; D008297:Male; D016488:Medicine, African Traditional; D010437:Peptic Ulcer / Q000139:chemically induced / Q000517:prevention & control*; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D010946:Plants, Medicinal; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000187:drug effects
chemical_list: D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D010936:Plant Extracts; D000431:Ethanol; D019342:Acetic Acid; D006851:Hydrochloric Acid