Abstract:
Background: Medicinal plants continue to play central roles in the healthcare system of a
large proportion of the world’s population. Aim: To determine the acute and Sub-chronic
oral toxicity of Melissa officinalis essential oil and to serve as criteria to recommend the
ethno pharmacological uses of the plant. Methods: In the acute toxicity test, oral
administration of 300 and 2000mg/kg of the Melissa officinalis essential oil was evaluated in
mice. Sub-chronic toxicity was studied by a daily oral dose of 100 and 200mg/kg for three
months. On day 0, 30, 60 and 90, blood samples collected from retro-orbital sinus of the eye
rats were used for evaluation of serum biochemistry, hematology and histopathological
examination of the heart, lungs, liver, kidney and spleen. Results: The acute toxicity oral
study revealed no observable signs of toxicity. In rats, the examination of signs, animal
behavior and the changes in body and organs weights showed no abnormalities in the test
groups as compared to the controls. There were no significant variations in the hematological
parameters of both Melissa officinalis essential oil treated and untreated rats. However,
biochemical parameters showed a significant decrease in blood sugar. Melissa officinalis
essential oil significantly (p<0.05) increased serum urea suggesting degenerative changes in
the kidney. Conclusion: We can conclude that Melissa officinalis essential oil is well
tolerated in short-term therapies but may have long-term toxic effects on the kidney.
