Toxicity profile of the methanolic leaf extract of eucalyptus globulus in Swiss albino mice and Wistar albino rats

Abstract

Background Eucalyptus globulus (Myrtaceae) is one of the plants widely used by many traditional healers in Uganda to prepare decoctions for treatment of a range of bacterial and fungal infections of the gastrointestinal tract; respiratory and urinary system. Scientific validation to support the use of this plant had been carried out and documented. However, knowledge about its safety was insufficient. Since several studies have documented that long term use of extracts from plants even at low doses may cause potential toxicity and even death, it was necessary to conduct this study. This is because there is wide spread use of this plant and the essential oil from it as a phytomedicine in Uganda and the rest of the world. Objectives

The study evaluated the toxicity profile of the crude methanolic extract from the leaves of this plant in mice and rats. Specifically it determined the acute toxicity of crude leaf methanolic extract of E. globulus in mice, and the haematological, biochemical and histopathological parameters of the rats after sub chronic administration of the extract. Method

An experimental study design was used in the study. Crude methanolic extract was prepared from dried leaves of E. globulus. Acute and sub chronic toxicity studies were carried out using standard procedures. Biochemical and haematological analysis were performed on blood samples of the rats after 14 and 21 days while histopathological evaluation on selected organs after 42 days of daily single oral dose of the extract. The results were compared with the control group and expressed as mean ± standard error of the mean. They were statistically analyzed using Dunnet test at 95% confidence.

Results

Acute toxicity results showed that the methanolic extract of E. globulus is safe in mice when administered in a single dose within 24 hours. Also there were non significant alterations in most of the haematological and biochemical parameters of the animals after 21 days of single daily dose except for the neutrophils and lymphocytes which were significantly increased. The extract also did not cause significant damage to the kidney, liver, heart, intestines and lungs after 42 days of daily extract administration.

Conclusion

The study conclude that the methanolic leaf extract of E. globulus does not cause significant acute toxicity in Swiss albino mice and sub acute toxicity in Wistar albino rats. Thus the extract is safe when administered over a short period of time.