Molluscicidal Activity Research Articles

A Comprehensive Review of the Ethnotraditional Uses and Biological and Pharmacological Potential of the Genus Mimosa.

The Mimosa genus belongs to the Fabaceae family of legumes and consists of about 400 species distributed all over the world. The growth forms of plants belonging to the Mimosa genus range from herbs to trees. Several species of this genus play important roles in folk medicine. In this review, we aimed to present the current knowledge of the ethnogeographical distribution, ethnotraditional uses, nutritional values, pharmaceutical potential, and toxicity of the genus Mimosa to facilitate the exploitation of its therapeutic potential for the treatment of human ailments. The present paper consists of a systematic overview of the scientific literature relating to the genus Mimosa published between 1931 and 2020, which was achieved by consulting various databases (Science Direct, Francis and Taylor, Scopus, Google Scholar, PubMed, SciELO, Web of Science, SciFinder, Wiley, Springer, Google, The Plant Database). More than 160 research articles were included in this review regarding the Mimosa genus. Mimosa species are nutritionally very important and several species are used as feed for different varieties of chickens. Studies regarding their biological potential have shown that species of the Mimosa genus have promising pharmacological properties, including antimicrobial, antioxidant, anticancer, antidiabetic, wound-healing, hypolipidemic, anti-inflammatory, hepatoprotective, antinociceptive, antiepileptic, neuropharmacological, toxicological, antiallergic, antihyperurisemic, larvicidal, antiparasitic, molluscicidal, antimutagenic, genotoxic, teratogenic, antispasmolytic, antiviral, and antivenom activities. The findings regarding the genus Mimosa suggest that this genus could be the future of the medicinal industry for the treatment of various diseases, although in the future more research should be carried out to explore its ethnopharmacological, toxicological, and nutritional attributes.

Molluscicidal activity of the Bacillus velezensisis Y6 strain against Oncomelania hupensis and its preliminary mechanisms of molluscicidal actions

To assess the molluscicidal activity of the of Bacillus Y6 strain against Oncomelania hupensis in laboratory, and to preliminarily investigate its mechanisms of molluscicidal actions. Biological identification of the Y6 strain was performed based on analysis of its morphological and physiochemical features and homology analysis of the 16S rDNA gene sequence. Bacillus Y6 suspensions were formulated at concentrations of 0.005, 0.010 g/mL and 0.015 g/mL, and the molluscicidal activity of Bacillus Y6 suspensions against O. hupensis was tested in laboratory using the immersion method. In addition, the Bacillus Y6 content and glycogen content were detected in O. hupensis following exposure to Bacillus Y6 suspensions to preliminarily explore the molluscicidal mechanism of the Bacillus Y6 strain against O. hupensis. The colony of the Bacillus Y6 strain appeared non-transparent milky white, and mycoderma was produced on the surface of the nutrient agar liquid medium. The Y6 stain was Gram positive and rod-shaped, and the endospore was located at the center of the Bacillus Y6 strain and appeared an achromatic, transparent and refractive body, which was encapsulated by the Y6 strain. The Y6 strain was positive for the lecithinase test, and the 16S rDNA gene sequence showed a 100% homology with those of multiple B. velezensisis strains, B. amyloliquefaciens and B. subtilis. The Y6 strain was therefore identified as B. velezensisis. Following immersion in the Bacillus Y6 suspensions at concentrations of 0.005, 0.010 g/mL and 0.015 g/mL for 24, 48 h and 72 h, the mortality rates of Oncomelania snails were 28.3%, 31.7% and 81.6%, 43.3%, 58.3% and 93.3%, and 63.3%, 78.3% and 98.3%, respectively. The molluscicidal activity of the Bacillus Y6 suspensions increased with the suspension concentration and duration of immersion. Microscopy and colony counting revealed the highest Y6 content in dead snails and the lowest in living snails following immersion in Bacillus Y6 suspensions, and the mean glycogen contents were (0.68 ± 0.06), (1.09 ± 0.16) μg/mg and (2.56 ± 0.32) μg/mg in the soft tissues of dead, dying and living snails following immersion in Bacillus Y6 suspensions (F = 59.519, P < 0.05), and the mean glycogen content was significantly higher in living snails than in dead (t = 14.073, P < 0.05) and dying snails (t = 10.027, P < 0.05), while the mean glycogen content was significantly higher in dying snails than in dead snails (t = 5.983, P < 0.05). The B. velezensisis Y6 strain shows a high molluscicidal activity against O. hupensis snails, and its invasion may cause glycogen metabolism disorders, leading to snail death.

Ecotoxicological evaluation of fruit extracts from yerba mate progenies (Ilex paraguariensis a St-Hil.): a natural biopesticide

This study evaluated the biocidal activity of aqueous fruit extracts from Ilex paraguariensis progenies at different ripening stages in two ecotoxicity assays using Pomacea canaliculata juveniles and Danio rerio larvae. Mutagenicity was verified by the Salmonella/microsome assay (TA 98 and TA 100) in the presence and absence of hepatic metabolism in vitro. The results showed that the snails were more sensitive than the larvae to the P.1 progeny extracts in all three evaluated ripening stages. P.3 progeny extracts were the most toxic to Danio rerio larvae after 96 hours of exposure. The toxicity results indicate that the progenies' selection influenced the metabolic contents present in the fruits in all ripening stages over time, indicating high molluscicidal activity for the P.1 progeny. In the Salmonella/microsome assays, the semi-ripe and ripe extracts from progenies P.1 and P.3 showed mainly base pair substitution mutation in assays with metabolism, but at higher doses than the toxic concentrations detected for Danio rerio or Pomacea canaliculata. Therefore, the toxicological investigation of the progenies' extracts can be interesting, given the selection of plant materials influenced the response of the bioassays.

MOLLUSCICIDAL ACTIVITY OF ZINGIBER OFFICINALE AND CARICA PAPAYA ON THE EGG HATCHABILITY OF THE GOLDEN APPLE SNAIL, POMACEA CANALICULATA (GASTROPODA: AMPULIRIIDAE)

The study was conducted to assess the effect of Zingiber officinale and Carica papaya extract on the egg hatchability of the golden apple snail, Pomacea canaliculata. This is a freshwater snail that is considered a pest in agriculture as well as natural ecosystems. In combating the population of the aforementioned pest, this study evaluates the use of plant extracts such as biomolluscicides to control the production of new hatchlings from the clusters of eggs. The egg clusters were exposed to different concentrations of Z. officinale ethanolic extract and C. papaya methanolic extracts (25 ppm, 50 ppm, 100 ppm) using the direct single spraying method. Observation was made for a maximum of 30 days. The time taken for the eggs to hatch and the number of eggs successfully hatched were measured to reflect the potential of both extracts in affecting egg hatchability. The finding shows that the eggs hatch later when exposed to increasing concentrations (25 to 100 ppm) of Z. officinale extract. The number of eggs successfully hatched was significantly decreased from 86% to 9% after exposure to 25 ppm and above. Meanwhile, the extract of C. papaya did not show any significant effect on both parameters for egg hatchability of P. canaliculata, regardless of the increase in concentration from 25 to 100 ppm. Our findings reveal that the extract of Z. officinale contains higher molluscicidal activity than the extract of C. papaya. Therefore, it has the potential to be commercialized as a biomolluscicide to control the population of golden apple snails specifically at the egg stage.

Discovery and Validation of a Novel Target of Molluscicides against Oncomelania hupensis, the Intermediate Host of Schistosoma japonicum

In this study, 196 strains of actinomycetes isolated from marshland soil samples were tested for molluscicidal activity against Oncomelania hupensis. Five strains demonstrated molluscicidal activity, of which the molluscicidal efficiency of Actinomycetes strain A183 was the maximum. After the fermentation supernatant of actinomycetes A183 was extracted with ethyl acetate (EWEA), the LC50 of the EWEA after leaching for 48 h and 72 h were 0.2688 and 0.2195 mg/L, respectively. The effect of EWEA on the key points of energy metabolism was determined. We noted that 1 mg/L of EWEA (A813) significantly reduced the activity of mitochondrial respiratory chain complex I (P < 0.05), while no significant changes were observed in the activities of complexes II, III, and IV. In addition, EWEA (A813) could decrease the membrane potential of O. hupensis purified mitochondria in vitro. The LC50 of the 3 uncoupler (FCCP, DNP, and Tyrphostin A9) after immersion for 24 h were 0.065, 0.135, and 0.110 mg/L, respectively; LC50 after 48 h treatment was 0.064, 0.124, and 0.082 mg/L, respectively; LC50 after 72 h treatment was 0.063, 0.129, and 0.061 mg/L, respectively, and all uncoupler showed strong molluscicidal activities, demonstrating that the mitochondrial membrane potential uncoupling is a potential target for molluscicides against O. hupensis. Moreover, the molluscicidal active substance of strain A183 needs to be further isolated, purified, and structurally characterized considering its promising potential applications.

Screening and functional verification of the target protein of pedunsaponin A in the killing of Pomacea canaliculata

Previous study found that pedunsaponin A (PA) influenced the cytoskeleton of Pomacea canaliculata hemocytes, leading to depolarization and haemocyte destruction and eventually to snail death. In this study, we analysed the changes in protein expression by iTRAQ-mediated proteomics and identified 51 downregulated proteins. Among these, we focused on proteins related to cytoskeletal function and identified neural Wiskott-Aldrich syndrome isoform X1 (PcnWAS). The full-length PcnWAS gene contains 9791 bp and includes an open reading frame of 1401 bp that encodes 735 amino acids with a predicted molecular mass of 49.83 kD. PcnWAS exhibited a relatively distant genetic relationship with known species; the closest homologue is Biomphalaria glabrata (57%). RNA interference (RNAi) was adopted to verify the function of PcnWAS after screening the siRNA sequence with an efficiency of 97%. Interference with the gene expression of PcnWAS did not lead to snail death, but the depolarization level increased, which demonstrated that PcnWAS is an important depolarization-related protein. The results of PA treatment of snails subjected to RNAi proved that interfering with PcnWAS gene expression decreased the molluscicidal activity of PA toward P. canaliculata; snail mortality after RNAi was significantly lower (40%) than that in PA-treated snails without RNAi (54%), while the survival rate and depolarization level in haemocytes were not significant, indicating that PcnWAS is only one of the important target proteins of PA in P. canaliculata. This study lays the foundation for further exploration of the molecular mechanism by which PA kills this harmful snail.

Laboratory Assessment of Molluscicidal and Cercaricidal Activities of Balanites aegyptiaca against Vectors of Schistosomiasis (Biomphalaria pfeifferi)

Studies were conducted on assessment of molluscicidal and cercaricidal activities of leaves, fruits and endocarp of Balanite aegyptiaca Del against adult vectors of schistosomiasis (Biomphlaria Pfeifeferi) using standard methods. Preliminary phytochemical screening was conducted, where alkaloids, saponins, flavonoids were found present in leaves, fruits, and endocarp. Molluscicidal and cercaricidal activity test were also conducted. Snail mortalities were compared between each plant part and snail specie as well as LC50 of the plant parts were also recorded. The result obtained revealed that leaves extract was more susceptible to the death of the snail species. Comparing LC50, the leaves extract shows 0.0726 considered as the highest cercaricidal while fruits and endocarp showed highest LC50of 0.0531 and 0.0426 respectively. Keywords: Balanites Aegyptiaca, Molluscicidal, Cercaricidal Activities, Schistosomiasis (Biomphalaria pfeifferi).

Essential Oils from Two Apiaceae Species as Potential Agents in Organic Crops Protection.

Chemical composition and herbicidal, antifungal, antibacterial and molluscicidal activities of essential oils from Choukzerk, Eryngium triquetrum, and Alexander, Smyrnium olusatrum, from western Algeria were characterized. Capillary GC-FID and GC/MS were used to investigate chemical composition of both essential oils, and the antifungal, antibacterial, molluscicidal and herbicidal activities were determined by % inhibition. Collective essential oil of E. triquetrum was dominated by falcarinol (74.8%) and octane (5.6%). The collective essential oil of S. olusatrum was dominated by furanoeremophilone (31.5%), furanodiene+curzurene (19.3%) and (E)-β-caryophyllene (11%). The E. triquetrum oil was tested and a pure falcarinol (99%) showed virtuous herbicidal and antibacterial activities against potato blackleg disease, Pectobacterium atrosepticum, and Gram-negative soil bacterium, Pseudomonas cichorii (85 and 100% inhibition, respectively), and high ecotoxic activity against brine shrimp, Artemia salina, and the freshwater snail, Biomphalaria glabrata, with an IC50 of 0.35 µg/mL and 0.61 µg/mL, respectively. Essential oil of S. olusatrum showed interesting antibacterial and ecotoxic activity and good herbicidal activity against watercress seeds, Lepidium sativum (74% inhibition of photosynthesis, 80% mortality on growth test on model watercress), while the furanoeremophilone isolated from the oil (99% pure) showed moderate herbicidal activity. Both oils showed excellent antifungal activity against Fusarium. Both oils and especially falcarinol demonstrated good potential as new biocontrol agents in organic crop protection.

Biological activity survey of Pereskia aculeata Mill. and Pereskia grandifolia Haw. (Cactaceae)

Background: Pereskia aculeata and P. grandifolia are non-traditional Brazilian vegetables with high nutritional value used in traditional medicine. The antioxidant, anticholinesterase, molluscicidal, cytotoxic, and antiproliferative properties of hydroethanolic extracts of P. aculeata and P. grandifolia leaves (PAL, PGL) and fruits (PAF, PGF) are investigated in this study. Methods: All extracts were prepared by maceration with ethanol 70%. Their antioxidant properties were assessed through DPPH, ABTS, FRAP, and β-carotene bleaching inhibition assays. A TLC bioautography method was employed to evaluate the inhibiting capacity of the acetylcholinesterase enzyme. The molluscicidal activity was tested against the snail Biomphalaria glabrata, which serves as an intermediate host for Schistosoma mansoni. The cytotoxic activity was assessed by a Artemia salina lethality test and the antiproliferative properties against seven human carcinoma cell lines. Results: Compounds with anticholinesterase activity were found in all extracts. Polar compounds present in PAF and PGL extracts were the most active (IC50 &lt; 25 μg of dry mass) and had an adequate inhibition capacity of the AChE. PGF and PGL were classified as moderate (LC50 = 19.2 μg/ml) and modest molluscicidal agents (LC50 = 66.6 μg/ml), respectively. All extracts exhibited selective antiproliferative activity against human chronic myeloid leukemia cell lines (K562). PAL, PGL, and PGF presented potent antiproliferative activity (TGI ≤ 5 μg/ml). Conclusion: Both species exhibited anticholinesterase, cytotoxic and antiproliferative properties. This research supports the potential of these species as sustainable sources of nutraceutical compounds.

Lantana camara Essential Oils from Vietnam: Chemical Composition, Molluscicidal, and Mosquito Larvicidal Activity.

Lantana camara is a troublesome invasive plant introduced to many tropical regions, including Southeast Asia. However, the plant does hold promise as a source of essential oils that may be explored for potential use. Fresh water snails such as Pomacea canaliculata, Gyraulus convexiusculus, and Tarebia granifera can be problematic agricultural pests as well as hosts for parasitic worms. Aedes and Culex mosquitoes are notorious vectors of numerous viral pathogens. Control of these vectors is of utmost importance. In this work, the essential oil compositions, molluscicidal, and mosquito larvicidal activities of four collections of L. camara from north-central Vietnam have been investigated. The sesquiterpene-rich L. camara essential oils showed wide variation in their compositions, not only compared to essential oils from other geographical locations (at least six possible chemotypes), but also between the four samples from Vietnam. L. camara essential oils showed molluscicidal activities comparable to the positive control, tea saponin, as well as other botanical agents. The median lethal concentrations (LC50 ) against the snails were 23.6-40.2 μg/mL (P. canaliculata), 7.9-29.6 μg/mL (G. convexiusculus), and 15.0-29.6 μg/mL (T. granifera). The essential oils showed good mosquito larvicidal activities with 24-h LC50 values of 15.1-29.0 μg/mL, 26.4-53.8 μg/mL, and 20.8-59.3 μg/mL against Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus, respectively. The essential oils were more toxic to snails and mosquito larvae than they were to the non-target water bug, Diplonychus rusticus (24-h LC50 =103.7-162.5 μg/mL). Sesquiterpene components of the essential oils may be acting as acetylcholinesterase (AChE) inhibitors. These results suggest that the invasive plant, L. camara, may be a renewable botanical pesticidal agent.

Evaluation of Kz Mineral Oil for Molluscicidal and Biochemical Activities against White Garden Snail Theba pisana (Müller) as a Safe Alternative to Pesticides and Honey Bee Apis mellifera L. Friendly Compound

Evaluation of Kz Mineral Oil for Molluscicidal and Biochemical Activities against White Garden Snail Theba pisana (Müller) as a Safe Alternative to Pesticides and Honey Bee Apis mellifera L. Friendly Compound

Molluscicidal activity of Ipomoea batatas leaf extracts against Pomacea canaliculata (Golden apple snail)

This study was conducted to investigate the molluscicidal activity of four different Ipomoea batatas (I. batatas) leaf extracts (hexane, chloroform, methanol, and aqueous extracts) against Pomacea canaliculata (P. canaliculata) and screen the phytochemical compounds of I. batatas leaf extracts. The golden apple snails (size range: 20–40 mm) were exposed to three concentrations (1000, 5000, and 10,000 ppm) of each extract (hexane, chloroform, methanol, and aqueous extracts). The efficacy of the I. batatas extracts was laboratory-tested by submerging the P. canaliculata into paddy-filled water mixed with the extracts and the mortality was observed every 24 hrs for 3 days. The presence of phytochemical compounds such as terpenoids, flavonoids, saponins, tannins, alkaloids, and glycosides were tested. For all extracts, the results showed a positive relationship between the concentration and the golden apple snail mortality, suggesting that all extracts have molluscicidal properties. The study showed more than 50% mortality rate of P. canaliculata after 72 hrs for each treatment. Chloroform and methanol I. batatas leaf extracts at 10,000 ppm showed 100% mortality after 72 hrs due to the presence of saponin. Saponin causes the death of the snails by disturbing their feeding and growth and blocking their breathing process. For further research, it is suggested to conduct the study under field trials in the search for a natural and environment-friendly molluscicide.

Lethal and antifeedant effects of Bordeaux mixture on the marsh slug (Deroceras laeve)

The marsh slug, Deroceras laeve (Müller), is a generalist pest of agricultural crops. Slugs are mainly managed with synthetic pesticides that can also have high toxicity toward vertebrates and nontarget arthropods. Besides, they are not labeled for use in organic crop systems. Bordeaux mixture (BM) is an alternative product often used in organic crops for controlling plant diseases. The molluscicidal activity of BM has been reported; however, to our knowledge, no study has determined its efficacy to control D. laeve. This study aimed to determine the lethal (concentration- and time–mortality curves, and foliar persistence) and antifeedant (reduction in leaf consumption) effects of BM-treated cabbage leaves on D. laeve. The LC50 of BM was 28.15%, and the LT50 was 8.83 h. The BM LC25 reduced D. laeve leaf consumption by 3.31-fold. Furthermore, high control effectiveness (mortality > 90%) was attained until the 7th day after spraying. These findings reveal that BM reduces damage by killing D. laeve in a fast faction and by reducing foliar consumption. Therefore, BM can be an alternative to D. laeve management in both conventional and organic systems.

Assessment of the molluscicidal activity of the methanolic seed extracts ofZiziphus spina‐christiandCarica papayaon immunological and molecular aspects ofBiomphalaria alexandrinasnails

Assessment of the molluscicidal activity of the methanolic seed extracts of<i>Ziziphus spina‐christi</i>and<i>Carica papaya</i>on immunological and molecular aspects of<i>Biomphalaria alexandrina</i>snails

Phytochemicals and Biological Activity of Desert Date (Balanites aegyptiaca (L.) Delile).

Many underutilized tree species are good sources of food, fodder and possible therapeutic agents. Balanites aegyptiaca (L.) Delile belongs to the Zygophyllaceae family and is popularly known as “desert date”, reflecting its edible fruits. This tree grows naturally in Africa, the Middle East and the Indian subcontinent. Local inhabitants use fruits, leaves, roots, stem and root bark of the species for the treatment of various ailments. Several research studies demonstrate that extracts and phytochemicals isolated from desert date display antioxidant, anticancer, antidiabetic, anti-inflammatory, antimicrobial, hepatoprotective and molluscicidal activities. Mesocarp of fruits, seeds, leaves, stem and root bark are rich sources of saponins. These tissues are also rich in phenolic acids, flavonoids, coumarins, alkaloids and polysterols. Some constituents show antioxidant, anticancer and antidiabetic properties. The objective of this review is to summarize studies on diverse bioactive compounds and the beneficial properties of B. aegyptiaca.

Essential oil from Piperaceae as a potential for biopesticide agents: a review

This review is aimed to present information on the properties of Piperaceae which can be potentially used as a biopesticide. The chemical compounds involved in were different as each species consist of different amount of secondary metabolites which then leads to different properties. In recent years, several reports have been published regarding the composition and the biological activities of the essential oils of Piper species. These studies have highlighted the existence of marked chemical differences among oils extracted from different species or varieties. Analysis of volatile constituents from Piperaceae species has revealed the presence of monoterpenes, sesquiterpenes and arylpropanoids that have shown interesting biological properties including cytotoxic, fungistatic, insecticide, molluscicidal, antioxidant and antimicrobial activities. Essential oils are natural complex secondary metabolites characterized by strong odour, volatility and have generally lower density than water. Due to their volatility, essential oils are environmentally non-persistent. On top of that, essential oils are ‘generally recognized as safe’ by the United States Food and Drug Administration (FDA). Since technology has become more advanced, people started to replace synthetic pesticide with bio-pesticide. The demand for EO has increased as it has biological properties that can be used to replace synthetic pesticide

Effect of Organic Waste Extracts as Potential Biocontrol of Golden Apple Snail

Golden apple snail (GAS; Pomacea canaliculata) is a member of the genus for freshwater snails with gill and operculum. It is an aquatic gastropod mollusc in the family Ampullariidae. This species has been introduced outside its native South American region and considered invasive because of its voracious appetite for paddy and other plants. In this study, the effect of bioresources and commercial waste were experimented to determine their effects on GAS. Garlic (Allium sativum) skins, groundnut (Arachis hypogaea) shells, used coffee (Coffea liberica) grounds and water spinach (Ipomoea aquatica) stems were extracted at 100 °C in aqueous system. The potential of these aqueous extracts as nanobiocontrol were investigated through the characterisation of particle size and molluscicidal activity. The results indicated that the aqueous extracts from water spinach (Ipomoea aquatica) in the form of nanoparticle (780.93 ± 2.45 nm) showed more lethal effect on GAS after 5 ± 1 min of exposure compared to used coffee grounds nanoparticle aqueous extract (553.64 ± 1.32 nm) at 45 ± 15 min, garlic skin aqueous extract (1381.34 ± 7.15 nm) at 8 ± 1 min and ground skin aqueous extract (1114.39 ± 10.35 nm) at 7 ± 2 min, respectively. These organic materials have the potential to be developed as biocontrol of GAS.

Caracterização química, atividade antimicrobiana e toxicidade dos óleos essenciais da Pimenta dioica L. (pimenta da Jamaica) e Citrus sinensis L. Osbeck (laranja doce)

Este estudo avaliou a toxicidade e a atividade antimicrobiana frente a Escherichia coli e Staphylococcus aureus dos óleos essenciais de Pimenta dioica Lindl. e Citrus sinensis L. Os óleos essenciais (OE) foram extraídos por hidrodestilação, com caracterização química através de cromatografia gasosa acoplada a espectrometria de massas (CG-EM). Os parâmetros físico-químicos foram determinados de acordo com a Farmacopeia Brasileira. O ensaio de toxicidade seguiu o bioensaio com Artemia salina Leach, os OE aprovados neste ensaio seguiram para avaliação das suas propriedades biológicas. A atividade antimicrobiana seguiu a metodologia descrita pelo Clinical and Laboratory Standards Institute utilizando o método de difusão de disco, diluição em caldo para concentração inibitória mínima (CIM) e posterior concentração bactericida mínima para avaliar a ação dos OE frente a Escherichia coli e Staphylococcus aureus. Ambos os OE apresentaram toxicidade baixa, e assim foram avaliados quanto as propriedades biológicas antimicrobianas. Ambos os OE apresentaram potenciais bactericidas frente aos microrganismos testados, exibindo resultados satisfatórios para a ação deles. Os resultados indicam que os OE avaliados são compostos por substâncias que propiciam e incentivam sua aplicação em virtude de seus potenciais para atividade biológicas moluscicida e antimicrobiana.

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

BackgroundFreshwater 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.MethodsIn 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.ResultsThe 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%.ConclusionsEssential 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.

Essential oils of the leaves of Syzygium cumini (L.) Skeels and fruit peels of Hymenaea courbaril (L.) var. courbaril as molluscides against Biomphalaria glabrata

This study evaluated the molluscicidal activity of essential oils (EOs) of Syzygium cumini L. and Hymenaea courbaril L. Hydrodistillation was used to extract the EOs. The chemical characterization was performed by Gas Chromatography coupled to mass spectrometry. The bioassay of Artemia salina Leach was used for the toxicity test. The molluscicidal assay tested concentrations of 10-80 mg L-1 of the EOs against Biomphalaria glabrata. The major constituent of The EO of S. cumini was isokaryophyllene and H. courbaril the Germacreno-D. The toxicity assay classified The EOs as nontoxic with LC50 412.10 mg L-1 for S. cumini and LC50 354.80 mg L-1 for H. courbaril. The molluscicidal assay purchased LC50 44.76/ LC90 77.20 for S. cumini and LC50 37.34 mg L-1/ LC90 73.24 mg L-1 for H. courbaril. The results showed that both EOs can be used as natural molluscicides in combating the snail Biomphalaria glabrata.