Effect of Mexican medicinal plant used to treat trichomoniasis on Trichomonas vaginalis trophozoites

Crude methanolic extracts from 22 Mexican medicinal plants were screened for antitrichomonal activity against Trichomonas vaginalis, which is the etiological agent of trichomoniasis. Among the plants tested Carica papaya and Cocos nucifera showed the best antitrichomonal activity with IC50 values of 5.6 and 5.8 μg/ml, respectively. The extracts of Bocconia frutescens, Geranium mexicanum, and Lygodium venustum showed moderate activity with IC50 values ranging from 30.9 to 60.9 μg/ml. All the other plant extracts were inactive (IC50 > 100 μg/ml). All extracts tested were less active than metronidazole (IC50 0.037 μg/ml), an antiprotozoal drug used as positive control. The results of the antiprotozoal screening support the popular uses of five of the plants tested for the treatment of some urogenital tract disorders in Mexican traditional medicine. However, seeds of Carica papaya and aerial parts of Bocconia frutescens should be used in herbal medicine with care to avoid toxicity.