Investigação química de extratos de Eremanthus erythropappus (DC.) MacLeish (Asteraceae) e seu potencial antiparasitário e de substâncias isoladas em vermes adultos de Schistosoma mansoni

Abstract

Neglected tropical diseases (NTDs), such as schistosomiasis caused by worms of the genus Schistosoma, are expressive helminthiases that affect more than 250 million people worldwide, where it is estimated that more than 300 thousand deaths occur annually due to infections caused by trematode worms. Alternatives in chemotherapy against this disease include, since its emergence in the 1970s, the pyrazinoquinolinic derivative praziquantel (PZQ), which, added to the resilience and adaptive potential of parasites, as well as a low bioavailability of PZQ, lead to greater complexity in the control of infections and elimination of these helminths. Thus, in the midst of the scarcity of antiparasitics, products of the secondary metabolism of plants still constitute a promising source of bioactive metabolites, which often in addition to their heterogeneity at the molecular level in active sites of diseases, are accompanied by low toxicity in animal models, thus regarded attractive for their pharmacological use. In this context, some species of the Asteraceae family, such as those of Eremanthus genera, have reported promising schistosomicidal activities in their essential oils and different plant extracts. Therefore, this work aimed to evaluate the schistosomicidal potential of E. erythropappus extracts and through annotation of compounds by analysis of MS/MS data, to conduct a chemical investigation of this species and later isolate antiparasitic activity related metabolites. Through the UHPLC-MS/MS analyses, sixteen compounds were annotated, where sesquiterpene lactones, pentacyclic triterpenoids and flavonol and flavone type flavonoids were majorly detected. From the LEE extract, the triterpenoids fridelin (1) and betulinic acid (2) and the flavone acacetin (3) were isolated, in which (2) and (3) are first reported in this species. Regarding evaluation of antiparasitic activity at in vitro assays against S. mansoni, the LEE extract showed to be more active than EEE, leading to death and reduction of motor activity of adult Schistosoma worms until 25μ/mL, where the investigation of the isolated metabolites related to such activity revealed promising schistosomicidal potential of compound (2), which after 48 hours post infection led to total elimination and complete mobility reduction of male and female worms at concentrations of 200μ/mL and 100μ/mL, maintaining this effect at 50μ/mL after 72 hours. Results obtained bring remarkable phytochemical knowledge and related to the antiparasitic potential of candeia-da-serra extracts.