RESUMO
Toxocara canis can produce the "larva migrans" syndrome in humans, and in puppies, it can cause severe digestive disorders. The most used treatments are based on anthelmintics, although there are reports of anthelmintic (AH) resistance. The Yucatan Peninsula has a great variety of plant species whose AH properties are still unknown. The objective of this study was to evaluate the in vitro AH activity of ethanolic (EE), methanolic (ME) and aqueous (AE) extracts from the leaves of five native plant species of the Yucatan Peninsula on T. canis eggs of dogs from Merida, Yucatan. As part of a screening, the EE of the plants Alseis yucatanensis, Calea jamaicensis, Cameraria latifolia, Macrocepis diademata, and Parathesis cubana were evaluated at doses of 2400 and 3600 µg/ml. The EE and AE of A. yucatanensis and M. diademata presented high percentages (≥ 91.3%) of inhibition of the larval development of T. canis after six days of exposure. The lowest LC50 and LC99 was presented by the ME from A. yucatanensis (255.5 and 629.06 µg/ml, respectively) and the ME from M. diademata (222.4 and 636.5 µg/ml, respectively), and the AE from A. yucatanenesis (LC50 of 535.9 µg/ml). Chemical profiling of the most potent AH extract (Alseis yucatanensis) was carried out by LC-UV-HRMS. Data from the ME and AE from this plant indicated the presence of the known glucosylngoumiensine, kaempferol 3,7-diglucosyde, uvaol, linoleic acid and linolenic acid together with unknown alkaloids. The EE, ME and AE from leaves of M. diademata and A. yucatanensis could be developed as natural alternatives to control T. canis.