Avaliação in vitro e in silico da atividade esquistossomicida de derivados eugenólicos utilizando ferramentas bioquímicas, moleculares e morfológicas

Abstract

Schistosomiasis is a chronic parasitic disease caused by parasites of the genus Schistosoma. Currently, chemotherapy is the immediate resource to minimize the prevalence and incidence of this disease worldwide, and the only medication indicated for treatment is praziquantel (PZQ). However, the dependence on a single drug is worrying, especially in endemic areas, where repetitive chemotherapy is constant, which may favor the appearance of strains resistant to the drug. Some competences of eugenol have been reported in the literature, such as antibacterial and antiparasitic activities. In this sense, this work aimed to evaluate the in vitro activity of eugenolic derivatives on adult worms from Schistosoma mansoni using biochemical and morphological tools; in addition to in silico analysis, in order to elucidate the mechanism of action of these compounds on the parasite. In this way, the use of different techniques helped to elucidate the means by which the eugenolic derivatives acted on the worm. After performing screening with different eugenolic derivatives at different doses, three compounds were selected and their ED50 was thus determined, thus being FB1 (62.19µg / ml), FB4 (41.04 µg / ml) and FB9 (100, 67 µg / ml). Thus, a biomolecular analysis was performed on the excretory system and skin damage of the parasite using fluorescence microscopy and scanning electron. In addition, biochemical tests were performed with verapamil and ouabain, antagonists of the calcium channels and the Na + K + ATPase pump, respectively. In addition, in silico analyzes were carried out to evaluate the interaction of the derivatives in question and these channels. The eugenolic derivatives caused damage to the tegument and the excretory system of the adult worms of S. mansoni, a fact confirmed by the fluorescent marking probes and scanning electron microscopy, mainly the FB4 derivative at 80 µg / mL concentration. In addition, it was possible to observe the delay in the death of adult worms by comparing the presence / absence of ouabain, 192 / 72h; 192 / 168h associated with FB1 and FB9, respectively. On the other hand, no changes were seen when in contact with the calcium channel antagonist, which only inhibited the action of PZQ. Thus, one of the likely mechanisms of action of eugenolic derivatives is related to sodium channel inhibition, which may be related to what has already been described for eugenolic compounds. It was observed that the compound that best interacted with these channels were FB1 and FB9, but they were the ones that had the highest ED50 and those with the least effect on the coat of adult worms. Conversely, the FB4 derivative was the one that least interacted in the in silico context and the one with the lowest ED50 and the greatest effect on the integument. In this way, it can be concluded that the eugenolic derivatives act on the parasite more actively when they act on the integument of the adult worms of S. mansoni.