Background and Objective: Current and common treatment of toxoplasmosis consist of oral adminstration of pyrimethamine and sulfadiazine. However, this drug combination has substantial toxicity and side effects on patients, especially in immunocompromised individuals. Echinacea purpurea is a medicinal plant with antimicrobial properties which boosts the immune system. This study was carried out to evaluate the anti-toxoplasma effect of E. purpurea extract in vitro and acute toxoplasmosis in a mouse model.

Materials and Methods: Parasite suspension containing 42000 live toxoplasma tachyzoites (RH strain) was added to serial concentrations of 50, 100, 200, 500 and 1000 µg/ml alcoholic extrac of E. purpurea and incubated at 37^oC for 5 hours. Then, IC₅₀ was calculated using linear regression. Subsequently, 48 BALB/c mice were asssigned to 5 treatment groups and a control group and were intraperitoneally infected with 10⁴ tachyzoites. 24 hours post infection, the E. purpurea extract was injected intraperitoneally by the aforementioned concentrations on a daily basis until the death of the mice. The control group received sterile saline. Survival time of the groups was analyzed by One way ANOVA and Duncan tests and between-group differences at the level of P<0.05 were considered statistically significant.

Results: Using linear regression, IC₅₀ values of E. purpurea extract was 784 µg/ml, after 5 hours. The mean survival time of the mice in the treated groups was significantly higher than the control group, respectively 6.5±0.9 and 5±0.0 days (P<0.05). The maximum survival time (7.3±1.0) without any significant difference with other test groups, was obtained in the fifth group (1000 &mug/ml).

Conclusion: The tested concentrations of alcoholic extract of E. purpurea did not pose any inhibitory effect on tachyzoites in vitro, but significantly increased the survival time of  the infected mice in vivo.