This study investigated the gastroptrotective effect of 1,8-cineole (cineol
e) on ethanol-induced gastric mucosal damage in rats and the possible mecha
nisms involved. 1,8-Cineole (50-200 mg/kg), given orally 1 hr before admini
stration of 1 mi of absolute ethanol significantly attenuated the ethanol-i
nduced gastric injury in a manner similar to nordihydroguairetic acid, a kn
own lipoxygenase inhibitor. 1,S-Cineole showed a tendency to restore the et
hanol-associated decreases in nonprotein sulfhydryls, suggesting a possible
antioxidant effect. In gastric secretion studies, 1,8-cineole, similar to
cimetidine, a known histamine-2 receptor antagonist, demonstrated significa
nt inhibitions of both gastric juice volume as well as total acid output. T
he protection offered by 1,8-cineole was found to be unaltered by 8-phenylt
heophylline or L-NAME, indicating that its effect is not mediated by endoge
nous adenosine or nitric oxide. These results, taken together with the earl
ier reports, suggest that the antioxidant and lipoxygenase inhibitory actio
ns of 1,8-cineole are of prime importance in affording gastroprotection aga
inst ethanol injury in the rat.