Molluscicidal activity of Persea americana Mill. (Lauraceae) stem bark ethanolic extract against the snail Biomphalaria glabrata (Say, 1818): a novel plant-derived molluscicide?

Plant-derived molluscicides have been indicated as biodegradable and low-cost strategies for control of Biomphalaria spp., intermediate host for the Schistosoma. This study evaluated whether the crude ethanolic extract of the Persea americana stem bark has molluscicidal activity against embryos, newly-hatched and adults of Biomphalaria glabrata. The extract was obtained, characterized and its toxicity analyzed by snail embryotoxicity test (144 h) and acute toxicity test with newly-hatching and adult snails (96 h). Results showed the presence of flavonoids, anthraquinone heterosides, coumarins and tannins in the crude ethanolic extract, which showed molluscicidal activity against all life cycle stages of B. glabrata. The LC50 for embryos, newly-hatched and adults were 27.06, 30.60 and 55.55 ppm, respectively. Embryos exposed to the extract at 50 ppm showed hatching inhibition and at 6.2 and 25 ppm had the highest rates of morphological alterations, such as shell malformations and coagulation of the perivitelline substance. Adult snails exposed to the extract at 75 ppm showed a peak of behavioral changes, such as lethargy and shell reclusion, in addition to answers like hemolymph release in most concentrations. Further studies are required, prioritizing toxicity testing on non-target organisms and further elucidation of the active molecules.

In silico search of energy metabolism inhibitors for alternative leishmaniasis treatments.

Leishmaniasis is a complex disease that affects mammals and is caused by approximately 20 distinct protozoa from the genus Leishmania. Leishmaniasis is an endemic disease that exerts a large socioeconomic impact on poor and developing countries. The current treatment for leishmaniasis is complex, expensive, and poorly efficacious. Thus, there is an urgent need to develop more selective, less expensive new drugs. The energy metabolism pathways of Leishmania include several interesting targets for specific inhibitors. In the present study, we sought to establish which energy metabolism enzymes in Leishmania could be targets for inhibitors that have already been approved for the treatment of other diseases. We were able to identify 94 genes and 93 Leishmania energy metabolism targets. Using each gene's designation as a search criterion in the TriTrypDB database, we located the predicted peptide sequences, which in turn were used to interrogate the DrugBank, Therapeutic Target Database (TTD), and PubChem databases. We identified 44 putative targets of which 11 are predicted to be amenable to inhibition by drugs which have already been approved for use in humans for 11 of these targets. We propose that these drugs should be experimentally tested and potentially used in the treatment of leishmaniasis.

Atividade tripanocida in vivo de Stryphnodendron adstringens (barbatimão verdadeiro) e Caryocar brasiliensis (pequi)

O Stryphnodendron adstringens e o Caryocar brasiliensis são espécies nativas do Cerrado e vem sendo testadas como forma alternativa no controle de parasitoses e vetores. Este trabalho avaliou a ação dos extratos bruto etanólicos das cascas destas espécies na concentração de 400 ppm, sobre a parasitemia do Trypanosoma cruzi. Camundongos foram infectados por via intraperitoneal com 1x104 formas tripomastigotas do parasito e após 24 h, inoculados por via intragástrica com dose única diária dos extratos durante dez dias. A avaliação de parasitemia foi efetuada em intervalos de 48 h até a morte dos animais. Os resultados demonstraram que durante as quantificações, os extratos de S. adstringens e de C. brasiliensis apresentaram uma significativa interferência sobre a curva de parasitemia do T. cruzi, reduzindo o número de parasitos no sangue.

Crude extracts from barks of Stryphnodendron adstringens and Caryocar brasiliensis, native species of Cerrado, have been screened at 400 ppm for antiparasitic activity against Trypanosoma cruzi. Mice were inoculated with 1x104 parasites, after 24 h they were treated with one day dose extracts during ten days. The trypanosomicidal activity was evaluated each 48 h until animals death. The extracts of S. adstringens and C. brasiliensis decreased significantly the number of parasites in the blood.

Plantas moluscicidas no controle dos caramuljos transmissores da esquistossomíase, com ênfase na ação de taninos / Molluscicide plants in the control of the snail, intermediate host of Scistosoma, with emphasis in tannins

Um dos alvos no controle da esquistossomíase é o controle dos oluscos, hospedeiros intermediários de Schistosoma spp, interrompendo assim o ciclo de vida do parasito e prevenimdo consequentemente a infecção humana. Várias espécies de vegetais são conhecidas por suas atividades moluscicidas, sendo, portanto, potencialmente úteis no controle das esquistossomíases intestinal e urinária transmitidas por moluscos Biomphalaria, Bulinus e Oncomelania, respectivamente, nas diferentes regiöes do mundo onde ocorrem. Esses moluscos têm sido controlados com a aplicação de substâncias naturais e/ou sintéticas...

Parasitismo natural de Bradybaema similaris (Férussac, 1821) por Postharmostomum Gallinum Witenberg, 1923 / Natural parasitism of Bradybaema similares (Férussac, 1821) by Postharmostomum gallinum Witenberg, 1923

Um total de 4.298 exemplares de Bradybaena similaris foram coletados na zona rural do município do Rio de Janeiro e nos municípios de Paracambi e Itaguai, RJ, entre outubro de 1983 e setembro de 1986. Destes caramujos, 2.005 apresentaram metacercárias livres na cavidade pericádica. As prevalências médias anuais foram de: 42,89% (primeiro ano), 43,42% (segundo ano) e 55,86% (terceiro ano). As metacercárias foram identificadas, através de infecçöes experimentais em pintos, como sendo de Posttharmostomum gallinum. A pouca variaçäo de tamanho entre as metacercárias de um mesmo hospedeiro indica que näo existe um recrutamento contínuo do parasito. Análise estatística mostrou que näo existe correlaçäo entre o tamanho do caramujo e o número de metacercárias presentes na cavidade pericárdica, e que a mortalidade dos caramujos, observada em laboratório, era devido a infecçäo parasitária