Vascular effects of Tanacetum vulgare L. leaf extract: in vitro pharmacological study.

AIM OF THE STUDY: Tanacetum vulgare L. (Asteraceae/Compositae) is principally used in traditional Moroccan medicine as antihypertensive remedy. The aim of the present study was to investigate the in vitro vascular activity of the aqueous extract of Tanacetum vulgare L. MATERIALS AND METHODS: The activity of Tanacetum vulgare L. extract was tested on contractile response of Wistar rat aorta to high KCl and noradrenaline and on endothelium-dependent relaxation evoked by acetylcholine. RESULTS: The addition of Tanacetum extract during the plateau phase of noradrenaline-evoked contraction produced a rapid relaxation that reached a maximum of 30% of the contraction and was suppressed by the NO synthase inhibitor N(G)-nitro-l-arginine. At higher extract concentrations this rapid relaxation was followed by a slowly developing, N(G)-nitro-l-arginine-resistant, relaxing effect. Tanacetum extract also depressed KCl-evoked contraction by 30% at maximum. This effect was abolished in the presence of N(G)-nitro-l-arginine. The endothelium-dependent relaxation induced by acetylcholine was depressed in the presence of Tanacetum extract in the bathing solution. CONCLUSION: This study indicates that the aqueous extract of Tanacetum possesses NO-mediated and NO-independent vasorelaxing properties in vitro.

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.

Diuretic activity of the aqueous extracts of Carum carvi and Tanacetum vulgare in normal rats.

In the Moroccan traditional medicine, the ripe fruits of Carum carvi L. (Apiaceae) and the leaves of Tanacetum vulgare L. (Asteraceae/Compositae), two widely available plant materials, are used as diuretics. Since, the diuretic activity of these substances has not been investigated in scientifically controlled studies, the aim of the present study was to evaluate the diuretic potential of aqueous extracts of Carum carvi fruit (caraway) and the leaves of Tanacetum vulgare (tansy) in normal rats after acute and sub-chronic oral administration. Water extracts of Carum carvi and Tanacetum vulgare (100 mg/kg) or the reference drug, furosemide (10 mg/kg) were administrated orally to male Wistar rats and their urine output was quantitated at several intervals of time after the dose. After single doses of the extracts of both caraway seeds and tansy leaves, urine output was significantly increased at all time points, and at 24 h after the dose, the total volume of urine excreted was similar for the plant extracts and furosemide. Both extracts increased urinary levels of Na(+) and K(+), to about the same extent, while furosemide increased urinary levels of only Na(+) and decreased urinary K(+). Despite changes in urinary excretion of the electrolytes, plasma Na(+) and K(+) levels were not affected by any of the three substances. In the 8-day sub-chronic study, all three substances induced significant diuresis and natriuresis; only tansy increased urinary potassium excretion. The plant extracts did not appear to have renal toxicity or any other adverse effects during the study period. In conclusion, water extracts of both Carum carvi and Tanacetum vulgare have strong diuretic action confirming their ethnopharmacological use. From the pattern of excretion of water, sodium and potassium, it may be deduced that there are atleast two types of active principals present in these extracts, one having a furosemide-like activity and the other a thiazide-like activity.