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Schistosomiasis has been controlled for more than 40 years with a single drug, praziquantel, and only one molluscicide, niclosamide, raising concern of the possibility of the emergence of resistant strains. However, the molecular targets for both agents are thus far unknown. Consequently, the search for lead compounds from natural sources has been encouraged due to their diverse structure and function. Our search for natural compounds with potential use in schistosomiasis control led to the identification of an algal species, Laurencia dendroidea , whose extracts demonstrated significant activity toward both Schistosoma mansoni parasites and their intermediate host snails Biomphalaria glabrata . In the present study, three seaweed-derived halogenated sesquiterpenes, (-)-elatol, rogiolol, and obtusol are proposed as potential lead compounds for the development of anthelminthic drugs for the treatment of and pesticides for the environmental control of schistosomiasis. The three compounds were screened for their antischistosomal and molluscicidal activities. The screening revealed that rogiolol exhibits significant activity toward the survival of adult worms, and that all three compounds showed activity against S. mansoni cercariae and B. glabrata embryos. Biomonitored fractioning of L. dendroidea extracts indicated elatol as the most active compound toward cercariae larvae and snail embryos.

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 (LC 50 ) 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 LC 50 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 LC 50 =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., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

Schistosomiasis is a parasitic disease that affects more than 250 million people. The treatment is limited to praziquantel and the control of the intermediate host with the highly toxic molluscicidal niclosamide. Marine algae are a poorly explored and promising alternative that can provide lead compounds, and the use of multivariate analysis could contribute to quicker discovery. As part of our search for new natural compounds with which to control schistosomiasis, we screened 45 crude extracts obtained from 37 Brazilian seaweed species for their molluscicidal activity against Biomphalaria glabrata embryos and schistosomicidal activities against Schistosoma mansoni . Two sets of extracts were taxonomically grouped for metabolomic analysis. The extracts were analyzed by GC-MS, and the data were subjected to Pattern Hunter and Pearson correlation tests. Overall, 22 species (60%) showed activity in at least one of the two models. Multivariate analysis pointed towards 3 hits against B. glabrata veliger embryos in the Laurencia/Laurenciella set, 5 hits against B. glabrata blastula embryos, and 31 against S. mansoni in the Ochrophyta set. Preliminary annotations suggested some compounds such as triquinane alcohols, prenylated guaianes, dichotomanes, and xenianes. Despite the putative identification, this work presents potential candidates and can guide future isolation and identification.

Introduction: In Brazil, Biomphalaria glabrata, B. tenagophila, and B. straminea are intermediate hosts of Schistosoma mansoni, the etiological agent of schistosomiasis mansoni. Molluscicide use is recommended by the WHO for controlling the transmission of this parasite. Euphorbia milii latex has shown promising results as an alternative molluscicide. Thus, a natural molluscicide prototype kit based on freeze-dried E. milii latex was developed and evaluated against Biomphalaria spp., Methods: E. milii latex was collected, processed, and lyophilized. Two diluents were defined for freeze-dried latex rehydration, and a prototype kit, called MoluSchall, was produced. A stability test was conducted using prototype kits stored at different temperatures, and a toxicity assay was performed using Danio rerio. Additionally, MoluSchall was tested against B. glabrata under semi-natural conditions according to defined conditions in the laboratory., Results: MoluSchall was lethal to three Brazilian snail species while exhibiting low toxicity to D. rerio. Regardless of storage temperature, MoluSchall was stable for 24 months and was effective against B. glabrata under semi-natural conditions, with the same LD100 as observed under laboratory conditions., Conclusions: MoluSchall is a natural, effective, and inexpensive molluscicide with lower environmental toxicity than existing molluscicides. Its production offers a possible alternative strategy for controlling S. mansoni transmission.

Schistosomiasis is a disease of global extent reaching populations in social vulnerability. One of the control measures of this parasitosis is the use of molluscicidal substances that can fight snails of the genus Biomphalaria, intermediate hosts of Schistosoma mansoni. The aim of this work was to study the toxic activity of three mangrove species (Avicennia schaueriana Stapf. & Leech, ex Moldenke, 1939, Laguncularia racemosa (L.) CF Gaertn, 1807 and Rhizophora mangle L. 1753) on the biological activities of snails Biomphalaria glabrata. Hydroalcoholic extracts were prepared from the stem and leaves of each of the three plant species to which mollusks were exposed. The phytochemical analysis of plants showed the presence of important metabolites in the leaves and stems of L. racemosa and R. mangle, such as tannins and saponins, but the absence of these metabolites in A. schaueriana. Leaf and stem extracts of the three plant species showed low molluscicidal activity, not reaching the standards determined by the World Health Organization (WHO, 1983). L. racemosa and R. mangle has interfered with motility, feeding and oviposition of snails, unlike the extracts of A. schaueriana, which had no effect on these activities.

Schistosomiasis is one of the neglected tropical diseases. It is a snail-borne trematode infection, and Biomphalaria alexandrina snails are the intermediate host of Schistosoma mansoni in Egypt. The objective of this study is to evaluate the molluscicidal activity of the aqueous seed extract of Moringa oleifera against B. alexandrina snails. The results showed that this aqueous extract was lethal for B. alexandrina snails (LC 50 0.27 g/l; LC 90 0.41 g/l). Exposure of snails to the sublethal concentrations of this aqueous extract caused a considerable reduction in survival rates and hatchability rates of eggs of these snails. Moreover, it negatively affected some biochemical aspects, where it increased the levels of transaminases (ALT and AST), while it decreased the concentrations of total protein, albumin, and globulin concentration. Histological examinations of the digestive gland of snails exposed to the sublethal concentrations of aqueous seed extract of M. oleifera revealed severe damage in the digestive cells, where they lost their tips and some were degenerated, while the secretory cells increased in number. Regarding the hermaphrodite gland, there were losses of connective tissues and irregular sperms, and the eggs were degenerated. These findings prove the potent activity of aqueous seed extract of M. oleifera against the intermediate hosts of Schistosoma mansoni and provide a considerable scope in exploiting local indigenous resources for snails' molluscicidal agents.

Context: The persistence of fascioliasis in many developing countries urges the search for simple, cheap, and effective substances. In this view, plants provide interesting molluscicidal activities thanks to the secondary metabolites they produce. The genus Solanum is known for its potent effect on vector snails., Objective: The molluscicidal activity of Solanum elaeagnifolium Cav. (Solanaceae) seeds against Galba truncatula Müll. (Lymnaeidae), intermediate host of Fasciola hepatica L. (Fasciolidae), was evaluated., Materials and Methods: Solanum elaeagnifolium seeds were powdered and successively extracted using n-hexane, methylene chloride, acetone, and methanol, for 20 h each. After filtration, solvents were evaporated. An acid-base treatment was conducted on seed methanolic extract to isolate total alkaloids and β-solamarine. Total saponins fraction was obtained after successive macerations and evaporations. The molluscicidal activity was evaluated by subjecting snails, in groups of 10, for 48 h to 500 mL of extracts, fractions, and pure product aqueous solutions, each containing amounts, ranging from 1 to 50 mg of plant material in 5 mg increments., Results: The methanolic extract of seeds, β-solamarine isolated for the first time from this plant and total saponins fraction showed very potent activities on snails, giving respective median lethal concentrations (LC50) of 1.18, 0.49, and 0.94 mg/L. Total alkaloids fraction obtained from the methanolic extract was less active giving an LC50 value of 14.67 mg/L., Discussion and Conclusion: This study emphasizes that glycoalkaloids and saponins of Solanum elaeagnifolium are potent molluscicidal agents. Seed methanolic extract, β-solamarine, and total saponins fraction may be used as molluscicides.

Cyanobacteria are a promising yet underexplored source for novel natural products with potent biological activities. While predominantly cytotoxic compounds have been isolated from cyanobacteria in the past, there are also a significant number of compounds known that possess anti-infective activities. As the need for novel anti-infective lead compounds is high, this manuscript aims at giving a concise overview on the current knowledge about anti-infective secondary metabolites isolated from cyanobacteria. Antibacterial, antifungal, antiviral, antiprotozoal, and molluscicidal activities are discussed. Covering up to February 2015., (Georg Thieme Verlag KG Stuttgart · New York.)

In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

Buddleja lindleyana is a medicinally important member of the family Loganiaceae distributed in Eastern China. The plant has been used in different traditional medications for the treatment of various diseases. Acacetin-7-rutinoside was isolated from the n-butanol fraction of fresh B. lindleyana leaves and found to be a new molluscicidal agent against the snail Oncomelania hupensis. The structure of acacetin-7-rutinoside was elucidated based on spectral data, including 1H NMR and 13C NMR.

Jatropha elliptica is a shrub distributed throughout the north and west of Brazil and reputedly possesses a wide range of therapeutical properties. The roots of this plant possess molluscicidal activity and contain terpenoids, coumarin, lignoid, steroids and alkaloid. In the present study, we assessed the schistosomicidal, miracicidal and cercaricidal activities (against Schistosoma mansoni) and molluscicidal activities (against adults and egg masses of Biomphalaria glabrata) of the alkaloid diethyl 4-phenyl-2,6-dimethyl-3,5-pyridinedicarboxylate, isolated from the ethanol extract of the rhizome of J. elliptica, have been determined. The alkaloid was 100% lethal to adult schistosomes within 4 days at a concentration of 50 μg/mL. Alterations were observed in the schistosome tegument occasioned by treatment with the alkaloid, such as formation of vesicles and vacuolisation. The extent of tegumental damage of the worm was proportional to the time of incubation and to the concentration of compound. The alkaloid also exhibited a potent cercaricidal activity (LC100 = 2 μg/mL); it was totally ineffective against miracicidal forms of the parasite. Moreover, the alkaloid presented strong activity against adult snails (LC90 = 36.43 μg/mL) but was inactive against their egg masses. It is observed then the potential of this compound for the development of new therapies for the treatment of schistosomiasis.

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).

Unlabelled: CONTEXT. Cymbopogon winterianus Jowitt ex Bor (Poaceae), known as citronella grass, is an aromatic herbaceous plant and the essential oil extracted from this grass is used in cosmetics, perfumes, hygiene and cleanliness products worldwide., Objective: This study investigated the composition and molluscicidal and larvicidal activities of the essential oil of C. winterianus cultivated in North Brazil., Materials and Methods: The oil was obtained by hydrodistillation, analyzed by gas chromatography (GC) and GC-mass spectrometry and then its molluscicidal and larvicidal activities against snails (Biomphalaria glabrata) and hatched larvae of Artemia salina, respectively, were evaluated at concentrations from 10 to 1000 mg/L., Results: The main constituents of oil were citronellal (26.5%), geraniol (16.2%), elemol (14.5%) and citronellol (7.3%). The molluscicidal test revealed significant lethal concentration (LC) values (LC90=97.0 mg/L, LC50=54.0 mg/L and LC20=22.0 mg/L), indicating the presence of molluscicidal compounds in the oil. In addition, the oil showed moderate larvicidal activity (LC50=181.0 mg/L) against the larvae of A. salina, which could justify its use in the aquatic environment without affecting other living organisms., Discussion and Conclusion: The results suggest that the oil of C. winterianus could be an effective alternative to control schistosomiasis, with an average margin of safety to other living organisms that coexist with snails.

The chemical composition and biological potential of the essential oil extracted from Syzygium cumini leaves collected in Brazil were examined. GC/MS Analyses revealed a high abundance of monoterpenes (87.12%) in the oil. Eleven compounds were identified, with the major components being α-pinene (31.85%), (Z)-β-ocimene (28.98%), and (E)-β-ocimene (11.71%). To evaluate the molluscicidal effect of the oil, it was tested against Biomphalaria glabrata and the LC₅₀ obtained was 90 mg/l. The essential oil also showed significant activity against Leishmania amazonensis, with an IC50 value equal to 60 mg/l. In addition, to evaluate its toxicity towards a non-target organism, the essential oil was tested against Artemia salina and showed a LC₅₀ of 175 mg/l. Thus, the essential oil of S. cumini showed promising activity as a molluscicidal and leishmanicidal agent and might be valuable in combating neglected tropical diseases such as schistosomiasis and leishmaniasis. Further research is being conducted with regard to the purification and isolation of the most active essential-oil compounds., (Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.)

Objective: To valuate the mollusicidal effects of some plants cultivated in the hilly and mountainous areas on Oncomelania hupensis and screen the plants against O. hupensis snails., Methods: The mollusicidal effects of water extracts of plant materials were tested in laboratory., Result: The LC50 of all the species in 24 h, 48 h, and 120 h reached the middle noxious level against O. hupensis snails. According to the taxis of LC50(s) in 120 h, Eucalyptus camaldulensis was best with a LC50 of 0.013%, and Ailanthus altissima, Zanthoxylum bungeanum, Juglans regia, Melia azedarach, Nerium indicum, Pterocarva stenobtera, Cinnamomum camphora, Vetiveria zizanioides, and Citrus reticulata were the second with LC50 (s) between 0.020% and 0.370%, and Zingiber officinale had a lower effect on snail control with a LC50 of above 0.500%. There was a correlation between the death rate of snails and soak time., Conclusion: The resources of snail-restrained plants are very abundant, and four plants, such as Eucalyptus camaldulensis, Ailanthus altissima, Cinnamomum camphora, and Vetiveria zizanioides have some mollusicidal effect.

Objective: To study biological safety of the molluscicidal ingredient (MI, a kind of diketopiperazines) in the exocellular broth of Aspergillus fumigatus SL-30' which was isolated from the rhizosphere of Phytolacca acinosa., Methods: The MI was prepared in concentrations ranging from 0.01 to 0.60 mg/L, at the same time molluscicidal activity against Oncomelannia hupensis was tested by using immersion method, and the LC50 in the case of immersion time for 24, 48 and 72 h was calculated. Acute toxicity of the MI with concentration ranging from 0.5 to 4.0 mg/L on Brachydanio rerio, Macrobrachium nippoensis and Rana limnochris was performed by standard laboratory procedure, and mortality rate of the tested animals with treated time of 24, 48 and 72 h was recorded. Effect of the MI on Eisenia fetida was tested using natural soil procedure with the dose of 1 and 10 mg/kg, and the poisoning performance and mortality in the 7th day and 14th day were recorded. Inhibition of the MI at 10 mg/kg on respiration of soil microorganisms was determined by sealed alkaline direct absorption method, and the released amount of CO2 (mg/100 g) in the 2nd, 5th, 7th, 10th, 12th and 15th day was determined., Results: Molluscicidal activity of the MI against Oncomelania hupensis was shown with LC50 0.101, 0.062, and 0.022 mg/L in 24, 48 and 72 h, respectively. Mortality rate of Brachydanio rerio, Macrobrachium nippoensis and Rana limnochris all increased with the increase of MI concentration, and the LC50 of each kind of tested animals was recorded as follows: 1.941, 1.755 and 1.219 mg/L for Brachydanio rerio, 3.170, 2.720 and 2.419 mg/L for Macrobrachium nippoensis, 2.109, 1.751 and 1288 mg/L for Rana limnochris in 24, 48 and 72 h, respectively. The LC50 of MI on Eisenia fetida was >10.0 mg/kg. The inhibition rate of MI was less than 50% with a concentration of 10 mg/kg in 15 days., Conclusion: The MI shows molluscicidal activity on Oncomelania hupensis with much lower toxicity on Brachydanio rerio, Macrobrachium nippoensis and Rana limnochrisn. The MI is safe to non-target aquatic organisms, and to both Eisenia fetida and soil microorganisms under the effective mollussicidal concentration.

Context: Balanites aegyptiaca (L.) Delile (Zygophyllaceae) is a tropical tree that has many folk uses in various countries. The bark extract is used for the control of the fresh water snails that act as intermediary host of Schistosoma., Objective: Study the molluscicidal activity and chemical constituents of seed oil and seed glycosides of B. aegyptiaca against Monacha cartusiana and determine the structure-activity relationship., Materials and Methods: Two bioassay methods (residual film application and the leaf dipping technique) were used to evaluate the toxicity effect of the seed oil and glycosides, in concentrations of 1.000, 0.500, 0.250 and 0.125%. The seed oil was analysed by GC/MS. Acid hydrolysis and chromatographic separation were used to study the seed saponins., Results: The bioassay of B. aegyptiaca against the land snail, M. cartusiana, indicated the activity of the seed oil and the high activity of the seed saponins. The seed glycosides gave 30.0, 53.3, 73.0 and 73.3% mortality for concentrations of 0.125, 0.250, 0.500 and 1.00%, respectively. The LC(50) values were 0.335 and 0.256%, respectively. The seed oil was analysed by GC/MS. Acid hydrolysis of the seed saponins gave a mixture of diosgenin, yamogenin and 3,5-spirostadiene., Discussion and Conclusion: To study the structure-activity relationship, a triterpenoidal saponin and a triterpenoidal saponins rich extract (of Zygophyllum coccenum) were proven to be inactive. Thus, the activity is associated with the steroidal, not triterpenoidal saponins. Moreover, a spirostane aglycone without sugar moiety, was found to be inactive and attained the activity by glycosidation.

The methanol (MeOH) extract of the twigs and leaves of Aglaia duperreana was investigated for its molluscicidal activity against Pomacea canaliculata. The extract was found to exhibit significant molluscicidal activity. The ethyl acetate soluble fraction of the extract showed the most potent molluscicidal activity among different solvent fractions. The bioactivity-guided chemical investigation of the ethyl acetate soluble fraction led to a new triterpenoid along with 15 known compounds. Their structures were elucidated by spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance techniques as well as mass spectroscopic analysis. The molluscicidal activities of compounds 2-16 against P. canaliculata were also investigated. Naringenin trimethyl ether showed significant molluscicidal activity with a median lethal concentration (LC(50)) of 3.9 μg/mL, which was indicated higher potency than the positive control, tea saponin (LC(50)=4.5 μg/mL)., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In this work, we have evaluated the molluscicidal activity of two cardenolide extracts from Adenium arabicum Balf f. [the benzene (B) and methanol (M) extracts], one cardenolide extract from Calotropis procera (Aiton) W.T. Aiton (extract C), and methomyl against the harmful land snail Monacha cantiana (Montagu). The contact LD₅₀ values for the above mentioned plant extracts were 12.62, 34.63, and 34.35 mg·kg⁻¹ of body weight, respectively, while the LD₅₀ for methomyl was 116.62 mg·kg⁻¹, that is, the plant extracts were 9.24, 3.37, and 3.4 times more toxic than methomyl. In addition, a simple colorimetric method, based on Kedde reagent, was modified to determine cardenolide concentrations in plant extracts. Thin layer chromatography analysis (TLC) showed several cardiac glycosidal compounds in each plant extract. The results proved that cardiac glycosides are promising candidate compounds that could be used to control land snails, or exploited to develop new, effective, and environmentally friendly molluscicides.

Bioactivity-guided separation of the aqueous methanolic extract of Yucca desmettiana leaves, which in a preliminary screening exhibited significant molluscicidal activity, led to the isolation and structure elucidation of two new steroidal saponins (1 and 2). The structures of desmettianosides A and B, identified as bisdesmosidic furostanol glycosides with six and five sugar units, respectively, were established by detailed spectroscopic analyses of their NMR and MS data. Compounds 1 and 2 exhibited high molluscicidal activity against Biomphalaria alexandrina snails with LC100 values of 6 and 11 mg/L, respectively., (Copyright © 2012. Published by Elsevier Inc.)

Freshwater snails of the genus Biomphalaria play a major role as intermediate hosts of Schistosoma mansoni, the etiologic agent of schistosomiasis. While Biomphalaria spp. control by molluscicides is one of the main strategies to reduce the snail population in infected areas, there are few effective molluscicides commercially available. Natural products may be considered as potentially useful and safe molluscicides. We have evaluated the molluscicidal activity of 12 extracts from ten marine organisms on adult and embryonic stages of Biomphalaria glabrata. Only extracts of the red algae Liagora farinosa and of the sponge Amphimedon viridis presented molluscicidal activity. Lethal concentration (LC)(50) values obtained were 120 μg/mL for L. farinosa CH(2)Cl(2) extract (apolar fraction) and 20 μg/mL for A. viridis extract and halitoxin. The polar alga fraction and halitoxin had no effect on B. glabrata embryos. The algae apolar fraction was active on B. glabrata in all embryonic development stages, with LC(50) values for blastulae at 42 μg/mL, gastrulae at 124 μg/mL, trochophore at 180 μg/mL, and veliger at 222 μg/mL. This is the first report of extracts from marine organisms which presented molluscicidal activity.

Jatropha curcas seed oil, which can be utilized for biodiesel production upon transesterification, is also rich in phorbol esters (PEs). In this study, PEs from J. curcas oil (Jatropha factors C₁ and C₂ (purified to homogeneity), Jatropha factors C₃ and (C₄+C₅) (obtained as mixtures) and PE-rich extract (containing all the above stated Jatropha factors) were investigated. The concentrations of Jatropha PEs were expressed equivalent to Jatropha factor C₁. In the snail (Physa fontinalis) bioassay, the order of potency (EC₅₀, μg/L) was: PE-rich extract

Two new triterpenoids, 2α-hydroxyurs-12-en-28-oic acid-3β-trans- isoferulate (1) and 2α, 3α, 24-trihydroxyolean-18-en-28-oic acid (2), together with three known triterpenoids (3-5) were isolated from the methanol extract of the bark of Eucalyptus exserta. Their structures were determined by spectroscopic means. Compounds 1, 2, and 5 exhibited molluscicidal activity against Pomacea canaliculata. All isolated compounds showed significant cytotoxic activity against Spodoptera litura (SL) cells., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Molluscicides can play an important role in the control of schistosomiasis because snails of the genus Biomphalaria act as intermediate hosts for the parasite. Schistosomiasis is one of 13 neglected tropical diseases with high morbidity and mortality that collectively affect one billion of the world's poorest population, mainly in developing countries. Thiopalmyrone (1) and palmyrrolinone (2), metabolites isolated from extracts of a Palmyra Atoll environmental assemblage of two cyanobacteria, cf. Oscillatoria and Hormoscilla spp., represent new and potent molluscicidal chemotypes against Biomphalaria glabrata (LC50=8.3 and 6.0 μM, respectively). A slight enhancement in molluscicidal effect (LC50=5.0 μM) was observed when these two natural products were utilized as an equimolar binary mixture.

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.

An unprecedented dimeric triterpenoid, designated dibelamcandal A, with a six-membered ring linking two iridal type triterpenoid nuclei, was isolated from the rhizome of Belamcanda chinensis. Its structure was determined by extensive spectroscopic measurements, including IR, ESI-MS, HR-ESI-MS, and 1D and 2D NMR. It demonstrated significant molluscicide activity against Pomacea canaliculata.

Molluscicidal activity of Solanum nigrum var. villosum (morelle velue) extracts and their fractions were tested against the mollusca gastropoda Galba truncatula intermediate host of Fasciola hepatica. The results indicated that the hydro-methanol (MeOH-H2O) immature fruit extract possess the highest molluscicidal activity (LC50 = 3.96 mg/L) against Galba truncatula compared with other tested compounds. After acido-basic treatment, the methanolic extract fraction isolated from the immature fruits and the richest in alkaloids was the most toxic (LC50 = 1.65 mg/L). The fractions richest in saponosides obtained from the hydromethanolic and methanolic extracts of immature fruits showed interesting molluscicidal activities (LC50 = 6.15 mg/L and LC50 = 7.91 mg/L, respectively). The observed molluscicide activity could be attributed to the presence of alkaloids or saponosides. So, the immature fruits of Solanum nigrum var. villosum could be substrates of choice for molluscicide activity. In addition, total alkaloids and saponosides present in this plant deserve further investigations in order to identify the active principles and demonstrate their activities on mollusks in their natural habitat. According to the World Health Organization's guidelines on screening for plant molluscicides, use of these fractions may add to the arsenal of methods to control snail transmitting fasciolosis in tropical and Third World countries where fasciolosis is a common disease.

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.

Five new prenylated phloroglucinols were isolated from the diethyl ether extracts of the ferns Elaphoglossum gayanum and E. piloselloides. Their structures were established by analysis of their spectroscopic data (1D and 2D NMR, HRMS, and IR) and chemical derivatization. The two major compounds exhibited moderate molluscicidal activity against the snail Biomphalaria peregrina, a vector of the tropical disease schistosomiasis, with LD(50) 7.2 microg/mL (14.4 microM) and 11.7 microg/mL (22.2 microM).

Over the last 50 years, molluscicides have played a critical role in the control of schistosomiasis transmission. Cyanolide A (2), isolated from extracts of a Papua New Guinea collection of Lyngbya bouillonii, is a new and highly potent molluscicidal agent against the snail vector Biomphalaria glabrata (LC(50) = 1.2 microM). The structure of cyanolide A (2) was elucidated through extensive NMR spectroscopic analyses, yielding a symmetrical dimer that represents the newest addition to the family of glycosidic macrolides from cyanobacteria.

Two new bicyclic phloroglucinols were isolated from the diethyl ether extract of an Argentine collection of the fern Elaphoglossum piloselloides. Structures were established by analysis of their spectroscopic data ((1)H NMR, HRMS, IR) and chemical derivatization. Both compounds show an acute molluscicidal activity against the schistosomiasis vector snail Biomphalaria peregrina.

Slugs are serious pests of oilseed rape (canola) and wheat with most damage occurring just after sowing and seedling emergence. As an alternative to the use of bait pellets, molluscicidal seed treatments have been shown to protect seeds and seedlings from slug damage in laboratory and semi-field experiments. However, protection offered to plants in field trials was diminished and shortlived in comparison with laboratory experiments. To determine why field efficacy was reduced, we grew seedlings under a range of environmental conditions, with appropriate controls, that simulated differences between laboratory and field experiments. We then measured the metaldehyde content of plant seedlings using a previously unpublished methodology described herein, which, unlike previous methods, did not first depolymerize the metaldehyde to acetaldehyde. We confirmed that naturally abundant plant-derived acetaldehyde could not interfere with our measurements of metaldehyde, even if depolymerization took place within the column. Our data suggest that reduced field efficacy results from microbial breakdown and/or loss of active ingredient caused by percolating soil water. Once the seedlings had emerged, neither volatalization nor simulated rainwater reduced the metaldehyde content of seedlings. Our findings will help develop superior seed treatment formulations to overcome these constraints.

Leishmaniasis, Chagas' disease and schistosomiasis (bilharzia) are parasitic diseases with wide distribution on the American continent, affecting millions of people. In the present study, biological assays for antiprotozoal and molluscicidal activities were carried out with ethanolic extracts of plant species from the Brazilian part of the Upper Paraná River. Crude extracts were obtained by percolation with absolute ethanol from the leaves of Cayaponia podantha Cogn., Nectandra falcifolia (Nees) Castiglioni and Paullinia elegans Cambess., as well as from the aerial parts of Helicteres gardneriana St. Hil. & Naud. and Melochia arenosa Benth., all belonging to genera used in folk medicine. Trypanocidal activity of plants was assayed on epimastigote cultures in liver infusion tryptose. Anti-leishmanial activity was determined over cultures of promastigote forms of the parasite in Schneider's Drosophila medium. Microscopic countings of parasites, after their incubation in the presence of different concentrations of the crude extracts, were made in order to determine the percentage of growth inhibition. C. podantha and M. arenosa, at a concentration of 10 microg/mL, showed 90.4 +/- 11.52 and 88.9 +/- 2.20% growth inhibition, respectively, of epimastigote forms of Trypanosoma cruzi, whereas N. falcifolia demonstrated an LD50 of 138.5 microg/mL against promastigote forms of Leishmania (Viannia) braziliensis. Regarding molluscicidal activity, the acute toxicity of the extracts on Biomphalaria glabrata was evaluated by a rapid screening procedure. M. arenosa was 100% lethal to snails at 200 microg/mL and showed an LD50 of 143 microg/mL. Screening of plant extracts represents a continuous effort to find new antiparasitic drugs.

Objective: To extract and purify the active component from Solanum for Oncomelania snail control, evaluate its effect against the snails and determine its chemical structure., Methods: Pedicel and seed were moved and the remaining part of the Solanum xanthocarpum fruit was torrefied and ground into powder. The powder was soaked into 95% ethanol and extracted. The residue was treated by ethyl acetate. 7 components were separated by methods of thin layer chromatography (TLC) and column chromatography (CCL). 4 main components were observed for the effect of snail-killing by immersion method. An alkaloid with Rf = 0. 58, named as component A, was confirmed as one of the effective components for Oncomelania snail control. The component A was further purified and received Al and A2 by proper elusion, and their effect was re-tested. The molecular weight and chemical structure of A2 were determined by MS, NMR and IR respectively., Results: The death rate of Oncomelania snails was 94.2% when the concentration of component A was 2.50 mg/L1(28 C ). The flow liquid system (ethyl acetate: chloroform: methanol 11:11:35) applied was the best reagent for separating component A. The death rate of Oncomelania snails in solution of A2 (0.2 mg/L) was 100% (28 degrees C). The molecular weight of A2 was 867 with an mp 298-305 C., Conclusion: The effective agent (A2),one of the active components from the fruit of Solanum xanthocar pum, is alpha-solamargine which shows an excellent effect in killing Oncomelania snails.

In a search for natural products that could be used to control the vectors of tropical diseases, 23 extracts of medicinal plants from the northeast of Brazil have been tested for molluscicidal activity against egg masses and adults of the snail Biomphalaria glabrata, for larvicidal activity against the larvae of the mosquito Aedes aegypti, and for general toxicity against the larvae of the brine shrimp Artemia salina. Of these extracts, two were active against the adult snail, one against snail egg masses, eight against the larvae of the mosquito, and 16 showed toxicity towards the brine shrimp. Chemical tests indicated that a wide variety of natural product classes were present in those extracts that showed significant activities in the bioassays.

The presence of saponins and the molluscicidal activity of the roots, leaves, seeds and fruits of Swartzia langsdorffii Raddi (Leguminosae) against Biomphalaria glabrata adults and eggs were investigated. The roots, seeds and fruits were macerated in 95% ethanol. These extracts exerted a significant molluscicidal activity against B. glabrata, up to a dilution of 100 mg/l. Four mixtures (A2, B2, C and D) of triterpenoid oleanane type saponins were chromatographically isolated from the seed and fruit extracts. Two known saponins (1 and 2) were identified as beta-D-glucopyranosyl-[alpha-L-rhamnopyranosyl-(1->3)- beta-D-glucuronopyranosyl-(1->3)]-3beta-hydroxyolean-12-ene-28 -oate, and beta-D-glucopyranosyl-(1->3)-beta-D-glucuronopyranosyl-(1 ->3)]-3beta-hydroxyolean-12-ene-28-oate, respectively. These two saponins were present in all the mixtures, together with other triterpenoid oleane type saponins, which were shown to be less polar, by reversed-phase HPLC. The saponin identifications were based on spectral evidence, including H- H two-dimensional correlation spectroscopy, nuclear Overhauser and exchange spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear multiple-bond connectivity experiments. The toxicity of S. langsdorffii saponins to non-target organisms was prescreened by the brine shrimp lethality test.

Alcoholic extracts of six Brazilian Cerrado medicinal plants were evaluated for their molluscicidal activity against Biomphalaria glabrata, intermediate host of schistosomiasis. Stryphnodendron polyphyllum bark extract, rich in condensed tannins, was the most promising as molluscicide.

Solanum aculeastrum Dunal was investigated for the presence of molluscicidal compounds. This led to the isolation of solaculine A, from the root bark in addition to known steroidal alkaloids; solamargine and beta-solamarine from the berries. The structures were elucidated by spectroscopic techniques. Molluscicidal activity of the aqueous extracts of the berries and root bark, and the isolated compounds were investigated.

Eleven known compounds and a new prenylated naphthoquinone, lippsidoquinone (13), were isolated from ethanol extracts of Lippia sidoides. Their structures were established by a combination of 1D and 2D NMR, IR, and EIMS spectral data analysis. The cytotoxic properties of compounds 3--13 were evaluated against HL60, SW1573, and CEM cell lines. Only tectol (6) and lippsidoquinone (13) exhibited significant activity against human leukemia cell lines HL60 and CEM.

Cryptomeria japonica against Acusta despesta. This hexane soluble-fraction was used to isolate and identify two sesquiterpenols, (-)-cubebol and (+)-2,7(14),10-bisabolatrien-1-ol-4-one, as the active compounds. Both compounds strongly inhibited the feeding behavior of A. despesta at 120 microg/cm2 and 80 microg/cm2 concentrations, respectively.

Two new hydrolyzable tannins, isoterchebulin (1) and 4,6-O-isoterchebuloyl-D-glucose (2), together with six known tannins, 3-8, were isolated from the bark of Terminalia macroptera. Their structures were elucidated by extensive 1D and 2D NMR studies, MS, and chemical transformations. Biological activities of all compounds were evaluated against the snail Biomphalaria glabrata, the bacteria Bacillus subtilis and Pseudomonas fluorescens, the nematode Caenorhabditis elegans, and four cancer cell lines (Hep G2, MCF-7/S, MDA-MB-231, and 5637 cells). All compounds except 3 showed antimicrobial activities against B. subtilis (MIC 8-64 microg/mL), whereas only 1 was active against C. elegans (100 microg/mL) and B. glabrata(LC(100) = 60 microg/mL). 3 and 8 were toxic against 5637 cells with LC(50) = 84.66 and 41.40 microM, respectively.

Molluscicidal activity of leaf, bark and seed of Lawsonia inermis against Lymnaea acuminata and Indoplanorbis exustus was studied. Highest toxicity was observed in the seed of Lawsonia inermis. Toxicity of binary (1:1) and tertiary (1:1:1) combinations of the essential oil of cedar (Cedrus deodara Roxh) and neem (Azadirachta indica A. Juss), powder from bulb of garlic (Allium sativum Linn), and oleoresin extracted from rhizome of ginger (Zingiber officinale Rosc) with Lawsonia inermis and Embelia ribes fruit powder were studied against L. acuminata and I. exustus. L. inermis seed powder in combination with Cedrus deodara oil and Azadirachta indica oil was more toxic than their individual components and other combinations.

A highly potent attachment-inhibitor, polygodial, was isolated from a hexane extract of the leaves of Tasmannia lanceolata. The attachment-inhibiting activity of polygodial against the blue mussel was increased 4-fold when used in combination with sorbic acid, anethole, and indole.

Five monodesmosidic serjanic acid saponins and a monodesmosidic spergulagenic acid saponin were isolated from an aqueous extract of the berries of Phytolacca icosandra. A methanol extract of the berries furnished three bidesmosidic serjanic acid glycosides. Their structures were established by spectroscopic (ES-MS, 1H NMR, COSY, HSQC, HMBC, 13C NMR) and chemical methods. The molluscicidal, spermicidal and haemolytic properties of the saponins were investigated.

In this study, we screened sixty medicinal plant species from the Brazilian savanna ("cerrado") that could contain useful compounds for the control of tropical diseases. The plant selection was based on existing ethnobotanic information and interviews with local healers. Plant extracts were screened for: (a) molluscicidal activity against Biomphalaria glabrata, (b) toxicity to brine shrimp (Artemia salina L.), (c) antifungal activity in the bioautographic assay with Cladosporium sphaerospermum and (d) antibacterial activity in the agar diffusion assay against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Pseudomonas aeruginosa. Forty-two species afforded extracts that showed some degree of activity in one or more of these bioassays.

Objective: To investigate the effect-increasing action of Areca catech for molluscacide., Method: Experiments were conducted on the effect-increasing components isolated from the dry nut of A. catech., Result: Arecoline has been proved the most effect-increasing component., Conclusion: When used with SPA arecoline could reduce markedly the doses of the two agents.

Marsypianthes chamaedrys is a common herb that occurs in the North and Northeast regions of Brazil. Phytochemical studies showed this plant to be rich in triterpenoids. The hexane extract of M. chamaedrys yielded, after chromatographic separations, two mixtures: the first containing monohydroxylated-compounds (alpha-amyrin, beta-amyrin, lupeol and germanicol) and the second, dihydroxylated compounds (chamaedrydiol, castanopsol, 2alpha-hydroxylupeol and epigermanidiol). Molluscicidal tests were performed for the crude hexane extract and for mixtures I and II. Mixture II showed high activity., (Copyright 1999 John Wiley & Sons, Ltd.)