ABSTRACT
Gastric ulcers were induced in the rat stomach by oral administration of ethanol/HCl [150 mM HC1 in 60% ethanol, 1 ml/ 100 g]. The protective effect of mastic gum, a resinous exudate of the tree of Pistacia lentiscus Linn Anacardiaceae, [500 mg/Kg], and vitamin E, a well known antioxidant, [100 mg/Kg] were investigated. Different gastric juice components [acidity, mucin and peptic activity] as well as gastric mucosal content of reduced glutathione, malondialdehyde, [as an index of lipid peroxidation] and prostaglandin E2 were estimated. Ethanol/HCl administration produced marked ulcers in the glandular part of rat stomach. Pretreatment with the protective agents significantly reduced the ulcer index and the protection afforded by mastic gum was greater than that of vitamin E. The protective effects of both mastic gum and vitamin E were accompanied by a significant decrease in mucosal content of malondialdehyde and a significant increase in mucosal content of reduced glutathione as compared to ethanol/HCl treated group. However, the anti-ulcer effect produced by mastic gum, only, was associated with a significant increase in mucosal content of prostaglandin E[2]. In 3-hour pylorus-ligated rats, mastic gum produced a significant decrease in free and total acidity while vitamin E caused no significant change in gastric acid secretion. The present data suggest that the anti-ulcer effect of mastic gum may be partly related to its antisecretory as well as antioxidant properties. On the other hand, the protective effect of vitamin E may be mainly related to its antioxidant effect