In vitro and in vivo anthelminthic activity of Stevia multiaristata extract on Echinococcus granulosus

Abstract

Cystic echinococcosis (CE) is a worldwide zoonotic disease caused by the larval stage of the parasite Echinococcus granulosus, which causes long-term infections in humans and animals, being a serious public health problem . Albendazole (ABZ), the main drug used against CE, has undesirable side effects and its efficacy is about 50%. Thus, new treatment alternatives are urgently needed. Plants from Stevia genus (Asteraceae) are a potential source of antiprotozoal and antimicrobial compounds. The antiparasitic activity of extracts from different Stevia species has recently been demonstrated on Trypanosoma cruzi and Leishmania braziliensis. In the current study, we demonstrated the in vitro efficacy of the Stevia multiaristata extract against protoscoleces and murine cyst of E. granulosus. Moreover, we investigated the clinical efficacy of the S. multiaristata extract in a murine model of CE. S. multiaristata extract caused a rapid decrease on protoscoleces viability, reaching 0% at day 6 with the concentration of 100 μg/ml. At the ultrastructural level, protoscoleces treated with 100 μg/ml experimented a total loss of morphology at day 3 post-incubation. Loss of turgidity was detected in 95% of cysts incubated during 2 days with 10 μg/ml and the collapse of the germinal layer was observed in 60% of cysts treated with 5 μg/ml during 4 days. Although the median weight of cysts recovered from ABZ treated mice was lower than the observed in the control group, no significant differences were found (P > 0.05). In contrast, S. multiaristata treatment caused a significant decrease in the weight of the cysts compared with control group (P < 0.05). In conclusion, S. multiaristata extract demonstrated a marked in vitro and in vivo effect against E. granulosus larval stage.