RESUMEN
OBJECTIVE: To detect the in vitro effect of the traditional Chinese medicine on the tachyzoites of Toxoplasma gondii. METHODS: Supernatant (1.5 ml) of different doses of the traditional Chinese medicine (Changqing capsule) was collected by normal saline immersion and 2.5 x 10(4) Toxoplasma gondii tachyzoites were added in each paste well for 8 hours. Spiramycin, pyrimethamine and azithromycin in different doses were used as controls. Normal saline was used as negative control. Mice were inoculated with drug-treated tachyzoites intraperitoneally or intragastrically. The normal mice were subcultured after 8 days for 3 generations. RESULTS: The incident number of the infected mice was significantly different among groups with different drugs and doses: 2/60, 16/60, 10/60 and 10/60 in the groups of Changqing capsule, spiramycin, pyrimethamine and azithromycin respectively (P < 0.05). No mice were found incident in groups of high and medium dose Changqing capsule while 2 out of 20 found sick in the low dose group (P < 0.05). The subculture observation showed that 2 and 1 mice in the first generation of the low dose Changqing capsule group inoculated intraperitonelly and intragastrically were found infected respectively. 2 mice of the second generation in low dose spiramycin group and 1 mouse of the third generation in low dose pyrimethamine group were also found infected. CONCLUSION: The in vitro killing effect of the Changqing capsule on the tachyzoites of Toxoplasma gondii is better than the current clinical drugs and shows a positive correlation with the dosages.