Acute and chronic toxicity of a lyophilised aqueous extract of Tanacetum vulgare leaves in rodents.

AIM OF THE STUDY: The present investigation was carried out to evaluate the safety of an aqueous extract of tansy (Tanacetum vulgare L.) leaves by determining its potential toxicity after acute and chronic administration in rodents.

MATERIALS AND METHODS: For the acute study, a lyophilized aqueous extract of tansy leaves was administered to mice in single doses of 0-13 g/kg given by gavage as well as intraperitoneal doses of 0-4.5 g/kg. General behavior adverse effects and mortality were determined for up to 14 days. In the chronic dose study, the extract was administered orally at doses of 0, 100, 300 and 600 mg/kg daily for 90 days to rats. Biochemical and hematological parameters were determined after 30 and 60 days, and then at the end of 90 days of daily administration.

RESULTS: In the acute study in mice, the crude aqueous extract of tansy leaves caused dose-dependent general behavior adverse effects and mortality. The no-observed adverse effect levels (NOAEL) of the tansy extract were 7.0 g/kg and 1.0 g/kg, and the lowest-observed adverse effect levels (LOAEL) were 9.0 g/kg and 1.5 g/kg, when given by the oral and intraperitoneal routes, respectively. Mortality increased with increasing doses, with LD(50) of 9.9 g/kg and 2.8 g/kg for the oral and intraperitonal modes of administration, respectively. In the chronic study in rats, daily oral administration of the crude aqueous extract of tansy leaves for up to 90 days did not result in death or significant changes in the biological (except for hypoglycemia) and hematological parameters.

CONCLUSIONS: Because of the relatively high NOAEL values in the acute study in mice, and lack of significant effect on biological and hematological parameters in rats after 90 days of daily doses, the tansy extract does not appear to have significant toxicity. In view of the dose of tansy consumed in traditional medicine, there is a wide margin of safety for the therapeutic use of the aqueous extract of Tanacetum vulgare leaves.