Prophylactic and healing properties of a new anti-ulcer compound from Enantia chlorantha in rats.

Decoctions prepared from Enantia chlorantha are used in the traditional treatment of some forms of ulcers. We have tested the anti-ulcer actions of a novel protoberberine-type alkaloid (7,8,-dihydro-8-hydroxypalmatine (1)) obtained from the bark of E. chlorantha using the HCl/ethanol, absolute ethanol and pylorus ligation techniques. The healing effect on chronic acetic acid-induced gastric ulcer was also tested. 1 (50 and 100 mg/kg) dose-dependently inhibited the formation of gastric ulcers induced by HCl/ethanol (35-52% inhibition), absolute ethanol (46-53% inhibition) and pylorus ligation (38-62% inhibition). The prophylactic actions were associated with significant increases in gastric mucus production compared with the controls. The significant inhibition of pylorus-ligated ulcers occurred at gastric acid concentrations (83 mEq/l) previously known to induce severe gastric ulceration in rats. The ulcer-healing test showed significant macromorphological and histological acceleration of healing following 10-day treatment with 1 (40 - 80 mg/kg). The results show that 1 has no anti-secretory effects. The prophylactic anti-ulcer effects are associated with enhanced mucus production, which is an important factor in the mechanism of the local healing process of chronic gastric ulcers.