The assessment of tolerability of prolonged oral eugenol administration in rats

The potential toxicity and general tolerability of eugenol following two-week or four-week continuous p.o. administration to rats has been investigated. An experiment was performed on 72 male rats of the Wistar strain. Four groups of rats were treated with different doses of eugenol (10 mg/kg bm/day, 50 mg/kg, 200 mg/kg and 400 mg/kg bm/day), the fifth group was administered vehicle (0.5 % methylcellulose, propylene glycol and water), and the sixth group comprised absolutely untreated controls. The corresponding doses of eugenol and vehicle were applied using a gastric probe in a volume of 1 ml/100 g body mass. The general tolerability of eugenol was evaluated on the basis of the daily intake of water and food, body mass, general health condition, behaviour, and lethality in the course of the experiment. In the investigated doses, eugenol applied p.o. in the course of two or four weeks does not influence significantly the intake of food, water, or body mass of rats. The dose of 400 mg/kg/day produced undesired reactions (agitation and hyperesthesia) that were first observed on day 21 and lasted until the end of the experiment. Low subacute toxicity of eugenol was established following p.o. administration to rats. Eugenol in doses of 200 and 400 mg/kg tm/day has a low toxic potential and is safe for administration to this animal species.