Ultrastructural study of morphological changes in Schistosoma mansoni after in vitro exposure to the monoterpene rotundifolone

Abstract

Introduction: Schistosomiasis, a parasitic disease caused by trematode flatworms of the genus Schistosoma, affects more than 200 million people worldwide, and its control is dependent on a single drug, praziquantel. Here, we report the in vitro effect of rotundifolone, a monoterpene isolated from Mentha x villosa (Lamiaceae), on Schistosoma mansoni adult worms. Methods: The in vitro effect of rotundifolone on adult Schistosoma mansoni was evaluated by analysis of behavior and mortality and through a scanning electron microscopic analysis of ultrastructural changes in the tegument of the worms. Results: At concentrations of 3.54 and 7.09μg/mL -1 rotundifolone, no worm mortality was observed at any of the sampling intervals. A minor reduction in movement of the tail, suckers, and gynecophoral canal membrane was observed after 96 h of exposure to 7.09μg/mL -1 rotundifolone. At 70.96μg/mL -1 , a lack of movement was observed from 72h onwards and all worms were deemed dead; similar effects were observed at 48h with 177.4μg/mL -1 , and at 24h with 354.8μg/mL -1 and 700.96μg/mL -1 . Rotundifolone also caused death of all parasites and separation of coupled pairs into individual males and females after 24h at 354.8μg/mL -1 . Conclusions: The main changes in the tegument induced by the different ROT treatments were: after 24h incubation, bubble lesions spread over the entire body and loss of tubercles occurred in some regions of the ventral region.

<p class="Body"><strong><em>Cymbopogon citratus</em></strong><strong> essential oil-induced ultrastructural &amp; morphological changes in the midgut, cuticle &amp; Haller’s organ of the tick <em>Haemaphysalis longicornis</em> (Acari: Ixodidae)</strong></p>

“…Other studies that corroborate these alterations observed thinness and disappearance of procuticle subdivisions after exposure to lufenuron (Mommaerts et al 2006;Sáenz-de-Cabezón et al 2006). The cuticular alterations could be caused by the monoterpene content of essential oils which caused bubble lesions over the entire body of treated Schistosoma mansoni (Matos-Rocha et al 2017). In the epithelial cells, the cytoplasmic vacuolization that was observed with an increase in the concentration of lemongrass essential oil could be attributed to the effect of α-terpineol-one of the monoterpene compounds in C. citratus essential oils, which also caused high vacuolization in the cells of T. mentagrophytes (Park et al 2009).…”

“…Additionally, some studies have attributed these induced ultrastructural and morphological alterations to the lipophilic monoterpene constituents of essential oils (Bakkali et al 2008;Matos-Rocha et al 2017). The passage of these lipophilic compounds through the integument, cell wall, and cell membranes may damage the structure of the cellular membrane which may rsult in cellular lysis (Bakkali et al 2008).…”

“…The passage of these lipophilic compounds through the integument, cell wall, and cell membranes may damage the structure of the cellular membrane which may rsult in cellular lysis (Bakkali et al 2008). It is also suggested that the activities of some essential oil could be a function of the ion loss, membrane potential reduction, proton pump collapse, and ATP pool depletion (Matos-Rocha et al 2017).…”