Extracts and Terpenoids from <i>Stevia</i> Species as Potential Anthelmintics for Neglected Tropical Diseases Caused by Cestode Parasites.

Abstract

Cestodes are etiological agents of neglected diseases such as echinococcosis and cysticercosis, which are major public health problems. Antiparasitic treatment relies on a small number of approved drugs, which are often only partially effective, poorly tolerated and require prolonged administration. Thus, the discovery of novel potential treatments is critical. The <i>Stevia</i> genus (Asteraceae) includes species that are recognized as a source of bioactive compounds, with many species associated with medicinal uses. In this study, the cestocidal activity of four South American <i>Stevia</i> species that previously showed antiprotozoal activity was analyzed using a motility assay on the laboratory cestode model, <i>Mesocestoides vogae</i>. The four <i>Stevia</i> extracts showed cestocidal activity, with <i>S. alpina</i> var. <i>alpina</i> as the most active. The sesquiterpene lactones estafietin and eupatoriopicrin were purified from <i>S. alpina</i> var. <i>alpina</i> and <i>S. maimarensis</i>, respectively, and tested on <i>M. vogae</i>. Estafietin showed cestocidal activity, inhibiting parasite viability in a dose-dependent manner, even from the first day of incubation. Consistent with the motility effects, the extract of <i>S. alpina</i> var. <i>alpina</i> and estafietin induced marked alterations in the morphology of the parasite. The results of this report show that <i>Stevia</i> species represent a source of new molecules with potential for the treatment of neglected tropical diseases caused by cestodes.