determination of safety margin for hepatotoxic effect of mentha longifolia essential oil in rat

background: mentha longifolia is one of the aromatic medicinal plant belongs to lamiaceae family. there are some active ingredients in the essential oil of m. longifolia, which potentially could impair the hepatic function. the aim of this study was to find the maximum dose of essential oil of m. longifolia (eoml) that does not show any hepatic deterioration. methods: adult wistar rats fed different doses of eoml as 50, 100, 200, 300, 400or 600 mg/kg, for two wk. after the completion of administration, the serum activity of alt, ast, and alpas the well-known liver toxicity enzymes and the serum total billirubine were measured, by spectrophotometer. the study was done at 2016 in isfahan pharmacy school, isfahan, iran. results: totally, 400 mg/kg of eoml significantly raised all of the evaluating factors compare to the control group. we found complete mortality in animals that received 600 mg/kg of eoml. conclusion: the essential oil of m. longifolia is not entirely safe especially for the liver. administration at the dose of 400 mg/kg leads to the hepatotoxic effect. the death occurred in the higher doses. the possible mechanisms for the eoml liver toxicity are triggering of oxidative stress or apoptosis by its ingredient like pulegone compound.