Barbatic acid from Cladia aggregata (lichen): Cytotoxicity and in vitro schistosomicidal evaluation and ultrastructural analysis against adult worms of Schistosoma mansoni.

Schistosomiasis is one of the most significant neglected tropical diseases, affecting around 260 million people worldwide, and Praziquantel is currently the only available drug for the treatment of infected persons. Thus, the search for new schistosomicidal compounds is urgent. The objective of this study was to investigate of the schistosomicidal effect of barbatic acid, a lichen metabolite, on adult worms of Schistosoma mansoni. The in vitro schistosomicidal effect was evaluated through the assessment of motility and mortality, cellular viability of the worms and ultrastructural analysis through scanning electron microscopy. To evaluate the cytotoxicity of barbatic acid, a cell viability assay was performed with human peripheral blood mononuclear cells. Barbatic acid showed a schistosomicidal effect after 3 h of exposure. At the end of 24 h the concentrations of 50-200 µM presented lethality on the worms. Motility changes were observed at sublethal concentrations. The IC50 obtained by the cell viability assay for S. mansoni was 99.43 µM. Extensive damage to the worm's tegument was observed from 25 µM. No cytotoxicity was observed on human peripheral blood mononuclear cells. This report provides data showing the schistosomicidal effect of barbatic acid on S. mansoni, causing death, motility changes and ultrastructural damage to worms. In addition, barbatic acid was shown to be non-toxic to human peripheral blood mononuclear cells at concentrations that are effective against S. mansoni.

Data set of the toxic effects of divaricatic acid depside on Biomphalaria glabrata and Schistosoma mansoni cercariae.

In this study, the molluscicidal and antiparasitic activities of divaricatic acid was evaluated, targeting the mollusc Biomphalaria glabrata and cercariae of the helminth Schistosoma mansoni. Divaricatic acid showed high toxicity against both adult snails (5.5 µg/mL) and embryos (20 µg/mL after 6 h of exposure). Similar activity was observed in S. mansoni cercariae after only a short exposure time. The divaricatic acid proved to be a promising substance for the control of the snail B. glabrata, an intermediate host of schistosomiasis, as well as the cercariae of the pathogen.

Laboratory assessment of divaricatic acid against Biomphalaria glabrata and Schistosoma mansoni cercariae.

In this study, the molluscicidal and antiparasitic activities of divaricatic acid was evaluated, targeting the mollusc Biomphalaria glabrata and cercariae of the helminth Schistosoma mansoni. In addition, the environmental toxicity of divaricatic acid was assessed by bioassay using the microcrustacean Artemia salina. Divaricatic acid showed high toxicity against both adult snails (5µg/mL) and embryos (20µg/mL after 6h of exposure). Similar activity was observed in Schistosoma mansoni cercariae after only a short exposure time (10µg/mL after 30min of exposure). The divaricatic acid did not show toxicity in the acute test using Artemia salina at concentrations equal to or below 200µg/mL. The divaricatic acid proved to be a promising substance for the elimination of the snail Biomphalaria glabrata, an intermediate host of schistosomiasis, as well as the cercariae of the pathogen, while being non-toxic to the Artemia salina at the same concentrations. This is the first experimental observation of the molluscicidal and cercaricide activity of divaricatic acid.

Teratogenic Effect of Usnic Acid from Cladonia substellata Vainio during Organogenesis.

Studies about toxicological potential of usnic acid are limited. This way, the vast majority of data available in the literature are related only to biological activities. This is the first study that aimed to evaluate the oral toxicity of usnic acid during the period of organogenesis. Females rats were distributed in the control groups, treated I and II, at doses of 15 and 25 mg/kg, administered by gavage during the 6° to 15° days of pregnancy. After 20 days the fetuses were removed and analyzed. A reduction in weight gain during pregnancy, increased resorption, reduction in the number of viable fetuses, and their body weight were observed. Morphological changes in the litter were visualized as exposure of the eye and atrophy of the limbs at the dose of 25 mg/kg. Histological analysis of the liver of the fetus showed reduction in the number of megakaryocytes between experimental groups and increase in the number of hepatocytes in a dose of 25 mg/kg. The experimental model used in this study reveals teratogenic effect of usnic acid in the period of organogenesis. Since this achievement, the importance of evaluating the toxic effects of natural substances is imperative, in order to elucidate the care in their indication as drug.