Ultrastructure and histopathological effects of some plant extracts on digestive gland of Biomphalaria alexandrina and Bulinus truncatus

The present investigation is concerning with studying the histopathological effects of three Egyptian wild plant-extracts, as botanic toxic agents; namely Euphorbia splendens (Euphorbiaceae), Ziziphus spina-Christi (Rhamnaceae) and Ambrosia maritima (Asteraceae) on the digestive gland of freshwater snails Biomphalaria alexandrina and Bulinus truncatus (uninfected and infected with Schistosoma mansoni and Schistosoma haematobium). In addition, ultrastructural studies carried out using the resulted effective plant against non-infected B. alexandrina and B. truncatus snails. According to the present results, E. splendens-plant was the most effective plant on the target two snails was E. splendens followed by Z. spina-chriti and the least molluscicidal activity was for A. maritima. Moreover, the susceptibility of B. alexandrina to the present target plants is higher than those of B. truncatus. The histopathological alterations due to the present three plants on the digestive gland of target snails included, cytoplasmic vacuolization and fragmentation and accumulation of the toxic agents of the target plants inside cytoplasm of digestive and excretory cells.Concerning histopathological effects of the present plants on digestive gland of infected-target snails, they showed numerous vacuoles in digestive and excretory cells. On the other hand, ultrastructural examinations due to the most effective plant “E. splendens” revealed cytoplasmic fragmentation in excretory cells and accumulation of the toxic agents of the plants inside digestive cells. Finally, it was recommended that the application of LC90 of E. splendens-extract in a trial to open new areas of application of extract of this plant as eco-friend molluscicide.