Activities of pumpkin seed oil against Biomphalaria alexandrina snails and the infective stages of Schistosoma mansoni with special emphasis on genotoxic and histopathological alterations.

Schistosomiasis is a serious health issue in tropical regions, and natural compounds have gained popularity in medical science. This study investigated the potential effects of pumpkin seed oil (PSO) on Biomphalaria [B.] alexandrina snails (Ehrenberg, 1831), Schistosoma [S.] mansoni (Sambon, 1907) miracidium, and cercariae. The chemical composition of PSO was determined using gas chromatography/mass spectrometry. A bioassay was performed to evaluate the effects of PSO on snails, miracidia, and cercariae. The results showed no significant mortality of B. alexandrina snails after exposure to PSO, but it caused morphological changes in their hemocytes at 1.0 mg/ml for 24 hours. PSO exhibited larvicidal activity against miracidia after 2 hours of exposure at a LC50 of 618.4 ppm. A significant increase in the mortality rate of miracidia was observed in a dose- and time-dependent manner, reaching a 100% death rate after 10 minutes at LC90 and 15 minutes at LC50 concentration. PSO also showed effective cercaricidal activity after 2 hours of exposure at a LC50 of 290.5 ppm. Histological examination revealed multiple pathological changes in the digestive and hermaphrodite glands. The PSO had genotoxic effects on snails, which exhibited a significant increase [p≤0.05] in comet parameters compared to the control. The findings suggest that PSO has potential as a molluscicide, miracidicide, and cercaricide, making it a possible alternative to traditional molluscicides in controlling schistosomiasis.

Evaluation of molluscicidal activity on Biomphalaria glabrata (Say, 1818) and phytochemical characterization of hydroalcoholic extract of leaves of Ricinus communis L. (EUPHORBIACEAE).

Schistosomiasis is a parasitic infection of great prevalence worldwide, affecting 250 million people in 78 countries. Faced with this problem, studies that seek to analyze molluscicidal activity from plant extracts have stood out. The present work aimed to obtain the phytochemical characterization and investigate the molluscicidal activity in the hydroalcoholic extract of Ricinus communis leaves on Biomphalaria glabrata. The hydroalcoholic extract was prepared by macerated with solvent ethanol P.A 96%, followed by filtration and concentration in rotary evaporator. Next, five groups of snails with 10 animals each, one being the negative control group, were submitted to treatments with four concentrations of 25, 50, 75 and 100 mg/L of hydroalcoholic extract of R. communis. The parameters mortality, physiological and behavioral aspects of mollusks were analyzed during 96h. The chemical characterization of the extract was performed by high-performance liquid chromatography coupled to mass spectrometry (LC-MS). Chemical characterization revealed the presence of tannins, flavonoids and ricinin alkaloid, but under the conditions analyzed, the presence of saponins was not observed. There was no significant molluscicidal activity of the extract. However, a greater influence was observed in the diet, in addition to the motility and physiological state of the snails (alteration of cephalopodal mass and oviposition). The toxicity test was performed with Artemia salina and no toxicity was observed for this microcrustacean. It is expected that the results obtained contribute to the fight against the expansion of schistosomiasis and that they make room for other studies that investigate the molluscicidal action of plant extracts.

Toxicity of plant-based silver nanoparticles to vectors and intermediate hosts: Historical review and trends.

Green nanoparticles (GNPs), mainly green silver nanoparticles (Ag NPs), have been recommended as sustainable and eco-friendly technologies to control vectors and intermediate hosts. The aim of the current study is to carry out a historical and systematic literature review about the use of green plant-based Ag NPs (GP-Ag NPs) to control medically important mosquito, tick and gastropods. Data about the number of studies published per year, geographical distribution of studies (mailing address of the corresponding author), synthesis type (plant species, plant structure and extract types), physicochemical properties of GP-Ag NPs, experimental designs, developmental stages and the toxic effects on mosquitoes, ticks and gastropods were summarized and discussed. Revised data showed that GP-Ag NPs synthesis and toxicity in mosquitoes, ticks and snails depend on plant species, plant part, extract types, exposure condition and on the analyzed species. GP-Ag NPs induced mortality, tissue damage, biochemical and behavioral changes in mosquitoes and reduced their fecundity, oviposition, egg hatching and longevity. Ticks exposed to GP-Ag NPs presented increased mortality and reduced oviposition, while on snails, studies demonstrated mortality, oxidative stress, and DNA damage. Immune responses were also observed in snails after their exposure to GP-Ag NPs. GP-Ag NPs reduced the reproduction and population of several vectors and intermediate hosts. This finding confirms their potential to be used in gastropod control programs. Future studies about current gaps in knowledge are recommended.

Immunotoxical, neurotoxical, histopathological and immunohistopathological alterations of Nerium oleander and Tecoma stans methanolic extract on Biomphalaria alexandrina snails.

Schistosomiasis is a severe illness that caused socioeconomic problems. The present study aimed to investigate the molluscicidal activities of the methanolic extract of Nerium oleander and Tecoma stans on B. alexandrina snails. The present results showed that N. oleander had the higher molluscicidal effect (LC50: 138.6 mg/l) than T. stans methanolic extract (LC50: 256.0 mg/l). These concentrations had no mortality effects on Daphnia magna during the first 12 h of the exposure, while, they had a cercaricidal activity. Exposure of B. alexandrina snails to the sub lethal concentrations (LC10 and LC25) of the methanolic extract of either N. oleander or T. stans caused a concentration- dependent significant decrease in their mean total number of hemocyte and hyalinocytes percent, while, both the round small and the granulocytes were increased than the control group. Exposure of B. alexandrina snails to LC25 of the methanolic extract of N. oleander or T. stans, caused morphological alterations in the hemocytes that were studied by both light and electron microscopy. The sub lethal concentration (LC25) significantly decreased the acetyl cholinesterase activities, acid and alkaline phosphatase levels and the protein content. Histopathological changes occurred in the digestive and the hermaphrodite glands of exposed B. alexandrina snails to LC25 of the methanolic extracts. These alterations were confirmed by Immunohistochemistry for PCNA and Cyclin D1 expressions. Conclusively, these plants could be used to decrease the spread of schistosomiasis as they are cheap and environmentally safe to replace the synthetic molluscicides for snail control.

Toxic, cytotoxic and genotoxic effect of saline extract and fraction of Parkia pendula seeds in the developmental stages of Biomphalaria glabrata (Say 1818 - intermediate host) and cercaricide activity against the infectious agent of schistosomiasis.

This study describes for the first time the effect of saline extract and Parkia pendula seed fraction on Biomphalaria glabrata adult embryos and molluscs well as the reproductive parameters (fecundity and fertility) and survival, in addition to cytotoxicity and genotoxicity through the profile of blood cells after exposure to sublethal concentrations. Furthermore, we analyzed the action of both preparations against the cercariae of Schistosoma mansoni and their environmental safety using the bioindicator Artemia salina. The saline extract and fraction showed toxic effects for embryos (CL90 of 464.25, 479.62, 731.28, 643.28, 408.43 and 250.94, 318.03, 406.12, 635.64, 1.145 mg/mL, for blastula, gastrula, trocophore, veliger and hippo stage respectively), adult snails after 24 h of exposure (CL90 of 9.50 and 10.92 mg/mL, respectively) with increased mortality after 7 days of observation and significant decrease (p <0.05; p < 0.01 and p < 0.001) in egg mass deposition. At sublethal concentrations, an increase in quantitative and morphological changes in hemocytes was observed, and in the genotoxicity/comet assay analysis, varying degrees of nuclear damage were detected. In addition, the saline extract showed changes in the motility of the cercariae, while the fraction howed toxicity from a concentration of 1.0 mg/mL. The saline extract showed toxicity to A. salina at the highest concentrations (3.0, 4.0 and 5.0 mg/mL), while the fraction did not show ecotoxicity. Thus, the saline extract and fraction was promising in combating schistosomiasis by eliminating the intermediate host and causing alterations and/or mortality to the infectious agent.

[Screening of traditional Chinese medicine-derived snail control drug targets based on network pharmacology].

OBJECTIVE: To screen the targets of traditional Chinese medicine-derived potential plant molluscicides based on network pharmacology and explore the mechanisms of molluscicidal actions. METHODS: The traditional Chinese medicines with molluscicidal actions were screened based on retrospective literature reviews, and their molluscicidal efficiency was summarized. The active ingredients and potential targets of traditional Chinese medicines were captured from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, Unified Protein Database and literature mining using network pharmacology. The drug-active ingredient-target network was created using the software Cytoscape 3.7.2, and the key targets were subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis using the Metascape software. RESULTS: A total of 27 types of snail control drugs derived from traditional Chinese medicines were screened from publications and classified into 14 categories. Network pharmacology identified 190 active ingredients, and the active ingredients with a high degree in the drug-active ingredient-target network included quercetin, linoleyl acetate, luteolin, beta-carotene, (24S)-ethylcholesta-5,22,25-trans-3beta-ol, fumarine and arctiin, with 181 corresponding potential targets screened. KEGG pathway enrichment analysis revealed that these targets were mainly located in 16 pathways, including the neuroactive ligand-receptor interactions, regulation of adipocyte lipolysis and adrenergic signal in myocardial cells. CONCLUSIONS: This study preliminarily demonstrates the multi-ingredient, multi-target and multi-pathway mechanisms of action of 27 molluscicides. The screened key ingredient may provide the basis for isolation, purification and pharmacological studies of molluscicides, and the screened key targets and key pathways may facilitate the illustration of mechanisms of actions of traditional Chinese medicine-derived molluscicides and development of novel green molluscicides.

Chemical composition and effect of Dysphania ambrosioides (L.) mosyakin & clemants essential oil on Biomphalaria tenagophila (D'Orbigny, 1835).

Dysphania ambrosioides (L.) Mosyakin & Clemants, known as santa maria herb, is a medicinal plant used on pest control and to treat parasitic diseases. Due to its potential for pest control, the aim of this work was to determine the chemical composition of D. ambrosioides essential oil and evaluate its molluscicidal effect on Biomphalaria tenagophila, which is an intermediate host for the Schistosoma mansoni trematode, that is responsible for causing human schistosomiasis. The essential oil extracted from its leaves showed 87% of (Z)-ascaridole and 100% of mortality against B. tenagophila at 10 ppm after 24 h of experiment. LC50 and LC90 values were, respectively, 2.40 (1.90-2.99) ppm and 8.75 (6.39-14.12) ppm. D. ambrosioides essential oil proved to be a promising natural molluscicide against schistosomiasis when compared with commercial products.

Screening of traditional Chinese medicine-derived snail control drug targets based on network pharmacology / 中国血吸虫病防治杂志

Objective To screen the targets of traditional Chinese medicine-derived potential plant molluscicides based on network pharmacology and explore the mechanisms of molluscicidal actions. Methods The traditional Chinese medicines with molluscicidal actions were screened based on retrospective literature reviews, and their molluscicidal efficiency was summarized. The active ingredients and potential targets of traditional Chinese medicines were captured from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, Unified Protein Database and literature mining using network pharmacology. The drug-active ingredient-target network was created using the software Cytoscape 3.7.2, and the key targets were subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis using the Metascape software. Results A total of 27 types of snail control drugs derived from traditional Chinese medicines were screened from publications and classified into 14 categories. Network pharmacology identified 190 active ingredients, and the active ingredients with a high degree in the drug-active ingredient-target network included quercetin, linoleyl acetate, luteolin, beta-carotene, (24S)-ethylcholesta-5,22,25-trans-3beta-ol, fumarine and arctiin, with 181 corresponding potential targets screened. KEGG pathway enrichment analysis revealed that these targets were mainly located in 16 pathways, including the neuroactive ligand-receptor interactions, regulation of adipocyte lipolysis and adrenergic signal in myocardial cells. Conclusions This study preliminarily demonstrates the multi-ingredient, multi-target and multi-pathway mechanisms of action of 27 molluscicides. The screened key ingredient may provide the basis for isolation, purification and pharmacological studies of molluscicides, and the screened key targets and key pathways may facilitate the illustration of mechanisms of actions of traditional Chinese medicine-derived molluscicides and development of novel green molluscicides.

Molluscicidal and parasiticidal activities of Eryngium triquetrum essential oil on Schistosoma mansoni and its intermediate snail host Biomphalaria glabrata, a double impact.

BACKGROUND: Freshwater snails are the intermediate hosts of a large variety of trematode flukes such as Schistosoma mansoni responsible for one of the most important parasitic diseases caused by helminths, affecting 67 million people worldwide. Recently, the WHO Global Vector Control Response 2017-2030 (GVCR) programme reinforced its message for safer molluscicides as part of required strategies to strengthen vector control worldwide. Here, we present the essential oil from Eryngium triquetrum as a powerful product with molluscicide and parasiticide effect against S. mansoni and the snail intermediate host Biomphalaria glabrata. METHODS: In the present study, we describe using several experimental approaches, the chemical composition of E. triquetrum essential oil extract and its biological effects against the snail B. glabrata and its parasite S. mansoni. Vector and the free-swimming larval stages of the parasite were exposed to different oil concentrations to determine the lethal concentration required to produce a mortality of 50% (LC50) and 90% (LC90). In addition, toxic activity of this essential oil was analyzed against embryos of B. glabrata snails by monitoring egg hatching and snail development. Also, short-time exposure to sublethal molluscicide concentrations on S. mansoni miracidia was performed to test a potential effect on parasite infectivity on snails. Mortality of miracidia and cercariae of S. mansoni is complete for 5, 1 and 0.5 ppm of oil extract after 1 and 4 h exposure. RESULTS: The major chemical component found in E. triquetrum oil determined by GC-FID and GC/MS analyses is an aliphatic polyacetylene molecule, the falcarinol with 86.9-93.1% of the total composition. The LC50 and LC90 values for uninfected snails were 0.61 and 1.02 ppm respectively for 24 h exposure. At 0.5 ppm, the essential oil was two times more toxic to parasitized snails with a mortality rate of 88.8 ± 4.8%. Moderate embryonic lethal effects were observed at the concentration of 1 ppm. Severe surface damage in miracidia was observed with a general loss of cilia that probably cause their immobility. Miracidia exposed 30 min to low concentration of plant extract (0.1 ppm) were less infective with 3.3% of prevalence compare to untreated with a prevalence of 44%. CONCLUSIONS: Essential oil extracted from E. triquetrum and falcarinol must be considered as a promising product for the development of new interventions for schistosomiasis control and could proceed to be tested on Phase II according to the WHO requirements.

Botanical Products in the Treatment and Control of Schistosomiasis: Recent Studies and Distribution of Active Plant Resources According to Affected Regions.

Schistosomiasis, a parasitic disease caused by trematodes of the genus Schistosoma, is the second most prevalent parasitic disease in the world. It affects around 200 million people. Clinical treatment, prophylaxis, and prevention are performed in countries susceptible to schistosomiasis. In the pharmacological treatment for an acute form of schistosomiasis, the use of antiparasitics, mainly praziquantel, is more common. As an alternative way, prevention methods such as reducing the population of intermediate hosts (mollusks) with molluscicides are important in the control of this disease by interrupting the biological cycle of this etiological parasite. Despite the importance of pharmacological agents and molluscicides, they have side effects and environmental toxicity. In addition, they can lead to the development of resistance enhancing of parasites, and lead to the search for new and effective drugs, including resources of vegetal origin, which in turn, are abundant in the affected countries. Thus, the purpose of this review is to summarize recent studies on botanical products with potential for the control of schistosomiasis, including anti-Schistosoma and molluscicide activities. In addition, species and plant derivatives according to their origin or geographical importance indicating a possible utility of local resources for countries most affected by the disease are presented.

Molluscicidal effectiveness of Luo-Wei, a novel plant-derived molluscicide, against Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus.

BACKGROUND: Control of snail intermediate hosts has been proved to be a fast and efficient approach for interrupting the transmission of schistosomiasis. Some plant extracts have shown obvious molluscicidal activity, and a new compound Luo-Wei, also named tea-seed distilled saponin (TDS), was developed based on the saponins extracted from Camellia oleifera seeds. We aimed to test the molluscicidal activity of 4% TDS against the intermediate host snails in China and Egypt, and evaluate its environmental safety to non-target organisms. METHODS: In the laboratory, Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus were exposed to 4% TDS, and the median lethal concentration (LC50) was estimated at 24, 48 and 72 h. In the field, snail mortalities were assessed 1, 2, 3 and 7 d post-immersion with 2.5 g/m3 4% TDS and 1, 3, 7 and 15 d post-spraying with 5 g/m2 4% TDS. In addition, the acute toxicity of 4% TDS to Japanese quail (Coturnix japonica), zebrafish (Brachydanio rerio) and freshwater shrimp (Macrobrachium nipponense) was assessed by estimations of LC50 or median lethal dose (LD50). RESULTS: In the laboratory, the LC50 values of 4% TDS for O. hupensis were 0.701, 0.371 and 0.33 mg/L at 24, 48 and 72 h, respectively, and 4% TDS showed a 1.975 mg/L [corrected] 24 h LC50 against B. alexandrina, and a 1.396 mg/L 24 h LC50 against B. truncatus. Across all study regions, the pooled mortalities of O. hupensis were 72, 86, 94 and 98% at 1, 2, 3 and 7 d, following field immersion of 4% TDS at a dose of 2.5 g/m3, and were 69, 77, 85 and 88% at 1, 3, 7 and 15 d, following field spraying at 5 g/m2, respectively. 4% TDS had moderate toxicity to Japanese quail (7 d LD50 > 60 mg/kg) and to shrimp (96 h LC50 = 6.28 mg/L; 95% CI: 3.53-11.2 mg/L), whereas its toxicity to zebrafish was high (96 h LC50 = 0.15 mg/L; 95% CI: 0.14-0.17 mg/L). CONCLUSIONS: 4% TDS is active against O. hupensis, B. alexandrina and B. truncatus under laboratory and field conditions, and it may be a candidate molluscicide of plant origin.

Extracts of the unripe fruit of Ilex paraguariensis as a potential chemical control against the golden apple snail Pomacea canaliculata (Gastropoda, Ampullariidae).

Plant extracts can provide a viable alternative to controlling many crop pests. This study sought to assess the efficacy of vegetable extracts of the unripe fruits of Ilex paraguariensis (yerba maté) for chemical control of the channeled apple snail (Pomacea canaliculata) and of non-target species as the South American catfish (Rhamdia quelen) under laboratory conditions. In P. canaliculata, the LC50 of the decoction extract was 31.39 mg.L-1 and the LT50 was over 26 h. The LC50 of the butanol extract was 24.75 mg.L-1 and the LT50 was in the range of 28 to 32 h. In juvenile R. quelen, the LC50 of the decoction was 17.98 mg.L-1 and the LT50 was in the range of 10-12 h. These extracts are particularly attractive considering the source of compounds and their effectiveness as molluscicides.

Apropos: critical analysis of molluscicide application in schistosomiasis control programs in Brazil.

Schistosomiasis is a snail-transmitted infectious disease affecting over 200 million people worldwide. Snail control has been recognized as an effective approach to interrupt the transmission of schistosomiasis, since the geographic distribution of this neglected tropical disease is determined by the presence of the intermediate host snails. In a recent Scoping Review published in Infectious Diseases of Poverty, Coelho and Caldeira performed a critical review of using molluscicides in the national schistosomiasis control programs in Brazil. They also described some chemical and plant-derived molluscicides used in China. In addition to the molluscicides described by Coelho and Caldeira, a large number of chemicals, plant extracts and microorganisms have been screened and tested for molluscicidal actions against Oncomelania hupensis, the intermediate host of Schistosoma japonicum in China. Here, we presented the currently commercial molluscicides available in China, including 26% suspension concentrate of metaldehyde and niclosamide (MNSC), 25% suspension concentrate of niclosamide ethanolamine salt (SCNE), 50% niclosamide ethanolamine salt wettable powder (WPN), 4% niclosamide ethanolamine salt dustable powder (NESP), 5% niclosamide ethanolamine salt granule (NESG) and the plant-derived molluscicide "Luowei". These molluscicides have been proved to be active against O. hupensis in both laboratory and endemic fields, playing an important role in the national schistosomiasis control program of China. Currently, China is transferring its successful experiences on schistosomiasis control to African countries. The introduction of Chinese commercial molluscicides to Africa, with adaptation to local conditions, may facilitate the progress towards the elimination of schisosomiasis in Africa.

Plant extracts, metaldehyde and saline solutions on the population control of Bradybaena similaris / Extratos vegetais, metaldeído e soluções salinas para o controle populacional de Bradybaena similaris

ABSTRACT: This study aimed to test the efficiency of plant extracts, metaldehyde and saline solutions, as alternatives to the population control of the snail Bradybaena similaris , and to investigate the effect of the plant extracts in reducing the damage of the snail on Brassica oleracea . The experiments were performed at the Entomology Laboratory of the Universidade Comunitária da Região de Chapecó (Unochapecó), using a random experimental design with nine treatments in triplicate. Five adult individuals of B. similaris were subjected to each trial, totaling 135 snails. The following treatments were tested: cinnamon ( Melia azedarach ), timbó ( Ateleia glazioveana ), rosemary ( Rosmarinus officinalis ), mate herb ( Ilex paraguariensis ), two concentrations of metaldehyde (3% and 5%), two concentrations of salt solution (5% and 10 %), and a control treatment (distilled water). To evaluate the survival of B. similaris it was checked the treatments every 24 hours, over four consecutive days. The results revealed that the two concentrations of metaldehyde were fully efficient, that the saline solution (10%) had and intermediate efficiency, and that all other treatments were not effective. The treatment with the M. azedarach extract induced a higher consumption of B. oleracea , while the saline solution at 10% and the extracts of R. officinalis and I. paraguariensis inhibited leaf consumption.

RESUMO: O objetivo deste trabalho foi avaliar a eficiência de extratos vegetais, metaldeído e soluções salinas como alternativas para o controle populacional de Bradybaena similaris e o efeito dos extratos para a redução dos danos sobre Brassica oleracea , em condições de laboratório (Laboratório de Entomologia da Unochapecó, Chapecó, Santa Catarina). O experimento foi conduzido utilizando cinco indivíduos adultos de B. similares para cada um dos nove tratamentos em triplicatas, totalizando 135 caracóis. Os seguintes tratamentos foram testados: extrato de cinamomo ( Melia azedarach ), timbó ( Ateleia glazioveana ), alecrim ( Rosmarinus officinalis ), erva-mate ( Ilex paraguariensis ), metaldeído (3% e 5%), soluções salinas (5% e 10%) e a testemunha (água destilada). Para avaliação dos dados, foi determinada a taxa de sobrevivência de B. similaris a cada 24 horas em um período de quatro dias. Os resultados obtidos indicam que as duas concentrações de metaldeído foram eficientes, a solução salina (10%) apresentou eficiência intermediária, enquanto os demais tratamentos não foram eficazes. Observou-se que o tratamento com extrato de M. azedarach induziu a um consumo maior de B. oleracea , enquanto a solução salina a 10% e os extratos de R. officinalis e I. paraguariensis inibiram o consumo.

OVICIDAL EFFECT OF PIPERACEAE SPECIES ON Biomphalaria glabrata, Schistosoma mansoni HOST / Efeito ovicida de espécies de Piperaceae em Biomphalaria glabrata, hospedeiro do Schistosoma mansoni

SUMMARY Schistosomiasis is a neglected disease with public health importance in tropical and subtropical regions. An alternative to the disease control is the use of molluscicides to eliminate or reduce the intermediate host snail population causing a reduction of transmission in endemic regions. In this study nine extracts from eight Piperaceae species were evaluated against Biomphalaria glabrata embryos at blastula stage. The extracts were evaluated in concentrations ranging from 100 to 10 mg/L. Piper crassinervium and Piper tuberculatum extracts were the most active (100% of mortality at 20 mg/L and 30 mg/L respectively). .

RESUMO A esquistossomose é uma doença negligenciada de importância para a saúde pública em regiões tropicais e subtropicais. Uma alternativa para o controle da doença é o uso de moluscicidas para eliminar ou reduzir a população de caramujo hospedeiro, acarretando uma redução da transmissão da doença nas regiões endemicas. Neste estudo, nove extratos vegetais provenientes de oito espécies de Piperaceae foram expostos a embriões de Biomphalaria glabrata no estágio de blástula. Os extratos foram avaliados em concentrações que variaram entre 100 e 10 mg/L, sendo Piper crassinervium e Piper tuberculatum os extratos mais ativos (100% de mortalidade a 20 mg/L e 30 mg/L respectivamente). .

Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca.

OBJECTIVE: To assess the molluscicidal and cercariacidal activities of aqueous extracts of Balanites aegyptiaca (B. aegyptiaca) against Ethiopian Biomphalaria pfeifferi (B. pfeifferi), Lymnaea natalensis (L. natalensis) and Schistosoma mansoni (S. mansoni) cercariae. METHODS: Extracts of seeds, endocarp, mesocarp, and fruit of B. aegyptiaca were tested for their activities against adult B. pfeifferi and L. natalensis. The cercariacidal activity of the seeds of the plant was also evaluated against S. mansoni. Bioassays were carried out following the methods recommended by WHO. Snail mortalities were compared between each plant part and snail species, and LC50 and LC90 values for the plant parts tested were computed. The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B. aegyptiaca seeds. RESULTS: For the molluscicidal activities of seeds, endocarp, mesocarp and whole fruit, the LC50 values against B. pfeifferi were 56.32, 77.53, 65.51 and 66.63 mg/L, respectively, while the respective LC90 values were 77.70, 120.04, 89.50 and 97.55 mg/L. Similarly, the LC50 values for the seeds, endocarp, mesocarp and whole fruit against L. natalensis were 80.33, 92.61, 83.52 and 87.84 mg/L, respectively, while the respective LC90 values were 102.30, 138.21, 115.42 and 127.69 mg/L. B. pfeifferi were found to be more susceptible to B. aegyptiaca than L. natalensis. S. mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice. The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract. CONCLUSIONS: The aqueous extracts of different parts of B. aegyptiaca exhibited reasonable molluscicidal activity against B. pfeifferi and L. natalensis, as well as cercariacidal activity against S. mansoni cercariae. However, comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other aquatic biota is not known.

Impact of Taraxerol in combination with extract of Euphorbia tirucalli plant on biological parameters of Lymnaea acuminata / Impacto do Taraxerol em combinação com o extrato da planta de Euphorbia tirucalli nos parâmetros biológicos da Lymnaea acuminata

The present work was carried out to evaluate the molluscicidal activity of active ingredient Taraxerol with the acetone extract of Euphorbia tirucalli against Lymnaea acuminata snail. The (fecundity, hatchability and survivability) of snail L. acuminata exposed to this extract was studied. The effects of the tested extracts on life-history traits of harmful snail L. acuminata have also been evaluated, and this study also expounds the inhibitory effects of these extracts singly as well as in binary combination (1:1 ratio). It concluded that these herbal products act as a potential source of molluscicides, and that they would also have the advantage of easy availability, low cost, biodegradability and greater acceptance amongst users than synthetic pesticide.

O presente trabalho foi levado a efeito para avaliar a atividade moluscicida do ingrediente ativo Taraxerol junto com o extrato de acetona da Euphorbia tirucalli contra o caramujo Lymnaea acuminata. Foram estudados a fecundidade, o desenvolvimento e sobrevivência do caramujo Lymnaea acuminata exposto a estes extratos. Os efeitos danosos destes extratos testados na vida do caramujo L. acuminata foram também avaliados e este estudo demonstra os efeitos inibidores destes extratos isolados ou em combinação binária (relação l:1). Concluiu-se que estes produtos vegetais agem como fontes potenciais de moluscicidas e que eles também têm a vantagem de obtenção fácil, baixo custo, biodegradabilidade e maior aceitação entre os usuários do que os pesticidas sintéticos.

Letalidade do extrato de synadenium grantii hook. F. (Euphorbiaceae) frente a caramujos biomphalaria glabrata say, 1818 (gastropoda, planorbidae) / Letalidad del extracto de synadenium grantii hook. F. (Euphorbiaceae) contra caracoles biomphalaria glabrata say, 1818 (gastropoda, planorbidae) / Lethality of synadenium grantii hook. F. (Euphorbiaceae) extract to snails biomphalaria glabrata say, 1818 (gastropoda, planorbidae)

No Brasil, o caramujo Biomphalaria glabrata Say, 1818 (Gastropoda, Planorbidae) atua como principal vetor hospedeiro intermediário do helminto trematódeo Schistosoma mansoni (Schistosomatidae), agente etiológico da esquistossomose. O combate deste hospedeiro com substâncias moluscicidas é considerado uma das formas de redução do risco de transmissão da esquistossomose. Na busca por novos produtos naturais para controlar este vetor, o presente trabalho testou os extratos de algumas espécies vegetais exóticas consideradas tóxicas: Allamanda cathartica L. (Apocynaceae), Breynia nivosa (W. Bull) Small (Phyllanthaceae), Croton floribundus Spreng. (Euphorbiaceae), Dieffenbachia picta Schott (Araceae), Euphorbia milii des Mol. var. breonii (Euphorbiaceae), Jatropha curcas L. (Euphorbiaceae), Monstera deliciosa Liebm. (Araceae) e Synadenium grantii Hook. f. (Euphorbiaceae). Apenas a espécie S. grantii apresentou atividade moluscicida (CL50 = 40,0 µg mL-1) promissora, sendo este o primeiro relato desta atividade para espécies do gênero Synadenium.

In Brazil, Biomphalaria glabrata Say, 1818 (Gastropoda, Planorbidae) snail serves as the principal intermediate vector host of Schistosoma mansoni (Schistosomatidae) trematode helminth, the etiologic agent of schistosomiasis. A way of reducing transmission risk of schistosomiasis is the combat of this host with molluscicide substances. In the search for new natural products to control this vector, the present study tested the extracts of some exotic plant species considered toxic: Allamanda cathartica L. (Apocynaceae), Breynia nivosa (W. Bull) Small (Phyllanthaceae), Croton floribundus Spreng. (Euphorbiaceae), Dieffenbachia picta Schott (Araceae), Euphorbia milii des Mol. var. breonii (Euphorbiaceae), Jatropha curcas L. (Euphorbiaceae), Monstera deliciosa Liebm. (Araceae) and Synadenium grantii Hook. f. (Euphorbiaceae). Only the S. grantii species showed molluscicide activity promising (LC50 = 40.0 mg mL-1), and this is the first report of this activity to the genus Synadenium (Euphorbiaceae).

En Brasil, el caracol Biomphalaria glabrata Say, 1818 (Gastropoda, Planorbidae) actúa como principal vector hospedero intermediario del helmintos trematodo Schistosoma mansoni (Schistosomatidae), agente etiológico de la esquistosomiasis. El combate de este hospedero con sustancias molusquicidas es considerado una de las formas de reducción del riesgo de transmisión de la esquistosomiasis. En la búsqueda por nuevos productos naturales para el control de este vector, el presente estudio examinó los extractos de algunas especies exóticas de plantas consideradas tóxicas: Allamanda cathartica L. (Apocynaceae), Breynia nivosa (W. Bull) Small (Phyllanthaceae), Croton floribundus Spreng. (Euphorbiaceae), Dieffenbachia picta Schott (Araceae), Euphorbia milii des Mol. var. breonii (Euphorbiaceae), Jatropha curcas L. (Euphorbiaceae), Monstera deliciosa Liebm. (Araceae) y Synadenium grantii Hook. f. (Euphorbiaceae). Sólo la especie S. grantii presentó actividad molusquicida prometedores (CL50 = 40,0 ug mL-1) promisora, siendo éste el primer relato de esta actividad para especies del género Synadenium.

Efficacy of euphorbia hirta latex as plant derived molluscicides against freshwater snails / Eficácia do látex da Euphorbia hirta como moluscicida vegetal contra caramujos de água doce

The toxic effect of binary and tertiary combinations of Euphorbia hirta Linn latex powder with other plant molluscicidal compounds, were evaluated against the freshwater snails Lymnaea (Radix) acuminata and Indoplanorbis exustus in pond. These combinations showed significant time and dose dependent effect against both the snails. These compounds at higher doses were also lethal to freshwater fish Channa punctatus (Bloch) (Channidae {Ophicephalidae}), which shares the habitat with these snails, but the LC90 (24h) doses of snails have no apparent killing properties in fish populations when treated in mixed population of snails and fish.

Os efeitos tóxicos das combinações binárias e terciárias do pó de látex da Euphorbia hirta Linn assim como outros compostos vegetais moluscicidas foram avaliados em sua ação sobre caramujos de água doce Lymnaea (Radix) acuminata e Indoplanorbis exustus em represas. Estas combinações mostraram significante efeito dose e tempo dependente contra ambos os caramujos. Estes compostos em doses altas foram também letais para peixes de água doce Channa punctatus (Bloch) (Channidae {Ophicephalidae}), que compartilham o ambiente com estes caramujos mas a dose LC90 (24h) para caramujos aparentemente não tem propriedade de matar as populações de peixes quando uma população mista de peixes e caramujos são tratadas.

Molluscicidal effect of Piper guineense.

The study was undertaken to assess the dosage-mortality ratio and toxic effects of Piper guineense fruit extracts on the adults of Biomphalaria pfeifferi, the snail intermediate host of Schistosoma mansoni, which causes intestinal schistosomiasis. The result showed significant toxic effects with crude ethanol and hot water fruits extracts. The estimated lethal dose concentration by arithmetic method (LC(50) and LC(90)) using both crude ethanol and hot water fruit media extracts were found to be (0.10 ± 0.04, 0.9 ± 0.2) mgl(-1) respectively for ethanolic extract and (5.0 ± 1.4, 8.5 ± 0.7) mgl(-1) respectively for hot water extract. Ethanolic extract was more potent than hot water extract. An all or none phenomenon appeared characteristic of the biological activity of these extracts. There was significant decrease in oviposition rate (p < 0.02). The extract from the fruits of this tropical plant holds promise in the control of Biomphalaria pfeifferi.