Antiulcerative properties and acute toxicity profile of some African medicinal plant extracts.

The aqueous extract of the stem bark of Tetrapleura tetraptera Schum et Thonn., Guibourtia ehie Leonard and the root extract of Taverniera abyssinica A. Rich. were used for the treatment of gastrointestinal related clinical problems in African ethnomedicine. HCl/EtOH-induced ulceration was used in fasted rat stomach to investigate the anti-ulcerative properties of the extracts. The acute cytotoxicity of the extracts using brine shrimp larvae was also investigated. The aqueous extracts of Tav. abyssinica (250-500 mg/kg), Tet. tetraptera (500-1000 mg/kg), G. ehie (500-1000 mg/kg) and a combination of Tet. tetraptera and G. ehie (1:4) (500-1000 mg/kg) produced significant (P < 0.05) inhibition (54-80%, 86-98%, 48-80% and 54-92%, respectively) of the HCl/EtOH-induced ulceration of the stomach compared with controls. The acute cytotoxic concentrations of the extracts which killed 50% (LC50) of brine shrimp within 24 h was 438 micrograms/ml for Tet. tetraptera, 220 micrograms/ml for the 1:4 combination of Tet. tetraptera and G. ehie and 1409 micrograms/ml for Tav. abyssinica. None of the shrimp were killed by G. ehie, even at 2 mg/ml.