Abstract

In the present study, we have examined the effects of an ethyl acetate extract ofMelaleuca bracteata on gastric acid secretion and indomethacin-induced ulceration. The plant is popularly known for its ornamental use in South Africa. Gastric acid secretion was studied using modified method of continuous acid secretion while gastric ulcers were produced in albino rats by oral administration of indomethacin. Results showed that, the extract significantly reduced gastric acid secretion in a dose-dependent fashion (P < 0.05). Similarly, in the animals pre-treated with extract and misoprostol, the mean ulcer scores of 4.90 ± 0.98 and 6.90 ± 0.60 respectively were significantly lower as compared to 13.42 ± 1.69 of the control (P < 0.05). This study also reports the isolation of 3-hydroxyl-lup-20 (30)-ene-28-oic (betulinic acid, BA), 3-hydroxylolean-12-ene-28-oic (oleanolic acid, OA) and its acetate from M. bracteata extract. The presence of BA and OA in the extract may account for its anti-ulcer effect.

Key words: Melaleuca bracteata, myrtaceae, gastroprotection, betulinic and Oleanolic acids.