Background:Oenanthe javanica (O.javanica) has been known to have high antioxidant properties via scavenging reactive oxygen species.We examined the effect of O.javanica extract (OJE) on antioxidant enzymes in the rat liver.Methods:We examined the effect of the OJE on copper,zinc-superoxide dismutase (SOD1),manganese superoxide dismutase (SOD2),catalase (CAT),and glutathione peroxidase (GPx) in the rat liver using immunohistochemistry and west blot analysis.Sprague-Dawley rats were randomly assigned to three groups;(1) normal diet fed group (normal-group),(2) diet containing ascorbic acid (AA)-fed group (AA-group) as a positive control,(3) diet containing OJE-fed group (OJE-group).Results:In this study,no histopathological finding in the rat liver was found in all the experimental groups.Numbers of SOD1,SOD2,CAT,and GPx immunoreactive cells and their protein levels were significantly increased in the AA-fed group compared with those in the normal-group.On the other hand,in the OJE-group,numbers of SOD1,SOD2,CAT,and GPx immunoreactive cells in the liver were significantly increased by about 190％,478％,685％,and 346％,respectively,compared with those in the AA-group.In addition,protein levels of SOD 1,SOD2,CAT,and GPx in the OJE-group were also significantly much higher than those in the AA-group.Conclusion:OJE significantly increased expressions of SOD 1 and SOD2,CAT,and GPx in the liver cells of the rat,and these suggests that significant enhancements of endogenous enzymatic antioxidants by OJE might be a legitimate strategy for decreasing oxidative stresses in the liver.