Inhibition of Trypanosoma cruzi by plant extracts used in Chinese medicine.

In this work, we assessed the effect of extracts obtained from 17 plants used in traditional Chinese medicine. These extracts were tested in vitro with the epimastigote form of Trypanosoma cruzi, clone Bra C(15) C(2), at 27 degrees C in F-29 medium at a concentration of 100 microg/ml in axenic cultures. Allopurinol was used as reference drug. Seven plant extracts showed inhibitory activities lower than 25%. Pueraria lobata, Mahonia beaei, Dictamus dasycarpus, Kochia scoparia, Sophora flavescens and Ligustrum lucidum showed effects with inhibition values between 25% and 60%, whereas Lithospermum erythrorhizon, Saussurea lappa, Melia toosendan and Cinnamomum cassia showed the greatest inhibitory activity of 100%. The IC(50) of these extracts were: 0.4, 2.4, 1.8 and 3.9 microg/ml, respectively. The MTT assay was made and did not show cytotoxic activity. These results allowed us to suggest that L. erythrorhizon, S. lappa, M. toosendan and C. cassia could be a source of new compounds against T. cruzi.