Toxicological screening of methanolic extract of Gmelina arborea in experimental animals

The present investigation was carried out to evaluate the safety of methanolic extract of Gmelina arborea bark (ME) by determining its potential toxicity after acute and repeated dose administration in rodents. In the acute toxicity study, the methanolic extract was administered orally to Swiss albino mice in single doses of 0, 300, 2000 and 5000mg/kg. General behavior and mortality was noted up to 14 days. For the repeated dose toxicity study, the extract was administered orally at doses of 0, 300, 1000 and 2000mg/kg for 28 days to Wistar rats. The effects on body weight, food and water consumption, organ weight, hematological parameters, biochemical parameters as well as histology of important organs were studied. In acute toxicity study, administration of methanolic extract not showed any general behavioral adverse effects and mortality at all selected doses. The no-observed adverse effect level (NOAEL) of methanolic extract was 5000mg/kg.

In repeated dose toxicity study, no mortality was observed when different doses of extract were administered daily for a period of 28 days. There were no significant differences in the body weight, organ weights and feeding habits between control and treated animals of both sexes. Repeated administration of methanolic extract did not caused any changes in hematological and biochemical parameters as compared with control. Histopathological examination of important organs at the end of study showed normal architecture indicating no morphological disturbances. The high NOAEL value in acute toxicity study and lack of significant effect on hematological parameters, biochemical parameters and histopathology in repeated dose toxicity study indicates that the methanolic extract of Gmelina arborea does not appear to have significant toxicity. Thus the methanolic extract of Gmelina arborea was found safe in acute and repeated dose toxicity studies.

Reference: [1] Rhiouani, H. et al. (2008). J. Ethnopharmacol. 118:378–386.