Molluscicidal Properties of Acacia nilotica.

The acetone, alcohol and aqueous extracts of fruits of ACACIA NILOTICA (L) W ILLD. ex D EL. (Mimosaceae) showed molluscicidal activity against BULINUS TRUNCATUS and BIOMPHALARIA PFEIFFERI, the two snail species which transmit schistosomiasis in the Sudan (S. haematobium and S. mansonii). TAN, a new vegetable molluscicide prepared from the aqueous extract of the fruits of A. NILOTICA was produced on a pilot scale by using the spray drying procedure. Due to the high content of tannins in the powder (more than 56%), the molluscicidal properties of this plant may well be due to these compounds.     

Molluscicidal properties of various saponins

A series of 24 different saponins isolated from various medicinal plants have been tested against BIOMPHALARIA GLABRATA, one of the snail vectors of schistosomiasis (bilharziasis). In general, monodesmosidic triterpenoid saponins exhibit strong molluscicidal activity whereas bidesmosidic saponins as well as the aglycones are fully inactive. Some dammarane glycosides and alkaloidal saponins have also been tested.     

On the molluscicidal activity of tannin containing plants

The aqueous and methanolic extracts of a series of typical tannin containing plants exhibit strong molluscicidal properties against the freshwater snail biomphalaria glabrata, which is the intermediate host of schistosomiasis. The crude extracts of Krameria triandra (Krameriaceae) and Arctostaphylos uvaursi (Ericaceae) were active at concentrations of 50 ppm. Hydrolyzable and condensed tannins are responsable for the molluscicidal activity. This report indicates a new class of plant derived compounds which may have important practical application for the control of schistosomiasis in endemic areas.     

Molluscicidal and antischistosomal activities of methanol extracts and isolated compounds from Eucalyptus globulus and Melaleuca styphelioides

Context: Schistosomiasis is a parasitic disease that results in severe organ damage. Snail control is the best measure to control schistosomiasis. Plant-derived molluscicides have gained increasing attention for the control of schistosomiasis because they have low toxicity towards non-target organisms. Tannins are particularly suitable for snail control because they are less toxic than saponins to non-target organisms.

Objective: To identify the most toxic components of two plants belonging to the family Myrtaceae, namely Eucalyptus globulus Labill. and Melaleuca styphelioides Sm against the different developmental stages of Schistosoma mansoni and its snail host.

Materials and methods: The 80% MeOH leaf extracts of the tested plants and their isolated compounds were screened for their molluscicidal activity (expressed as LC₅₀ and LC₉₀ after 24?h exposure) against the snail Biomphalaria alexandrina. The anti-schistosomal activity of the tested samples was determined at 20?ppm (after 1 or 2?h exposure) against the different developmental stages of S. mansoni, including the miracidia, cercariae and worms. Biochemical parameters were measured to determine the toxicity mechanisms of the treated snails. The structures of the isolated compounds were elucidated based on NMR, UV and HRESI-MS/MS data.

Results: Potent molluscicidal activity was observed for the ellagitannin dimer eucalbanin B (12), with an LC₅₀ value of 55?ppm. Treatment of the snails with the LC₂₅ of eucalbanin B (30.8?ppm) resulted in a significant decrease in the protein level by 22.7% and 25.8% in the snail tissues and hemolymph, respectively. The decreased protein content was attributed to destruction of the snail tissue and impairment in protein synthesis under stress conditions of intoxication with eucalbanin B. Alterations in the activities of the transaminases and phosphatases in the treated snails indicated destruction and intoxication of the snail tissues. A significant increase in the levels of the transaminases alanine aminotransferase (ALT) (57.8%) and aspartate aminotransferase (AST) (113.2%) in the snail hemolymph and a significant decrease in their tissue levels to 7.4 and 48.6%, respectively, were attributed to their release from the damaged tissue into the hemolymph. Alkaline phosphatase (ALP) was significantly increased by 38.5 and 181.4% in the hemolymph and tissues, respectively. Acid phosphatase (ACP) was also significantly increased by 48.4 and 21.2% in the hemolymph and tissues, respectively. The 80% MeOH extract of E. globulus together with mallophenol B (3), 2,2,8-trimethyl-6-formyl-chrom-3-ene-7-O-β-d-glucopyranoside (5) and benzyl alcohol 7-O-(3′,4′,6′-tri-O-galloyl)-β-d-glucopyranoside (10) exhibited miracidicidal activity with almost 100% toxicity at 20?ppm for the three compounds and 80% toxicity for the extract. Moreover, E. globulus extract showed cercaricidal and schistosomicidal activity with 100 and 40% mortality, respectively.

Conclusion: E. globulus is a potential source for biocidal compounds against S. mansoni and its snail host. This is the first study to test the biocidal activity of the isolated compounds.     

Screening of Panamanian Plants for Molluscicidal Activity

A total of 153 crude extracts of Panamanian plants (28 species from 21 families) have been screened for molluscicidal activity against Biomphalaria glabrata, one of the intermediate hosts of schistosomiasis. When tested at 400 ppm, 15 extracts were active. The most potent of these came from Cyperus luzulae (Cyperaceae) and Hymenaea courbaril (Leguminosae).     

Anacardic acid: molluscicide in cashew nut shell liquid

The components of anacardic acid, (a mixture of 6-n-C (15) alkylsalicylic acids whose side chains vary in degrees of unsaturation) have been isolated by high pressure liquid chromatography from a crude extract of cashew nut shell, ANACARDIUM OCCIDENTALE, and tested for toxicity to fresh water snails, BIOMPHALARIA GLABRATA. The triene component is the most toxic form (LC (50) 0.35 ppm), the diene and monoene components are less toxic (LC (50) 0.9 and 1.4 ppm), and the saturated component is relatively nontoxic (LC (50) > 5 ppm). Since decarboxylated anacardic acid (cardanol) and salicylic acid do not kill snails at concentrations up to 5 ppm, it appears that both, carboxyl group and unsaturated side chain are absolutely required for molluscicidal activity. The mechanism of toxicity of anacardic acid to snails is unknown.     

The toxic activities of Arisaema erubescens and Nerium indicum mixed with Streptomycete against snails

The comparative molluscicidal activities of Arisaema erubescens tuber extracts and Nerium indicum leaf extracts mixed with Streptomycete violacerruber dilution (SD) against the snail Oncomlania hupensis and the responses of the isozymes, esterase (EST) and superoxide dismutase (SOD) to the A. erubescens extracts and the mixtures were investigated. The molluscicidal activity of A. erubescens water extracts mixed with S. violacerruber dilution was 4-5 times higher than a single A. erubescens or S. violacerruber dilution after 24-h exposure, and is also higher than that of N. indicum leaf water extracts mixed with S. violacerruber dilution. At the end of exposure to the N-butanol extracts of A. erubescens tubers (NEAT), the EST activity in snail liver decreased and some enzyme bands (EST 1 and EST 3 in exposure to NEAT) disappeared but the activities of SOD 1 increased. The effect was more obvious in mixture treatment than in single NEAT or SD treatment. The results indicated that molluscicidal activities of plant and microorganism could be more effective than single plant. The decline of the detoxic ability in snail liver cells could be the reason of the snail dying.     

The molluscicidal activity of coumarins from Ethulia conyzoides and of dicumarol.

The molluscicidal principles of Ethulia conyzoides were identified as ethuliacoumarin A (1) and isoethuliacoumarin A (2). Ethuliacoumarin A possessed an LC90 between 19 and 23.5 ppm depending on the age of the snail against Biomphalaria glabrata, and between 12 and 15 ppm against Bulinus truncatus. In addition, ethuliacoumarin A was found to be cercaricidal at 25 ppm and ovicidal. Ethuliacoumarin has the structural requirements considered essential for anticoagulant activity. Consequently the anticoagulant dicumarol (4) was tested and found to be molluscicidal in the range from 2.5 to 10 ppm. In contrast, the coumarin anticoagulant warfarin (3) did not show molluscicidal activity.     

Toxic effect of two common Euphorbiales latices on the freshwater snail Lymnaea acuminata

The aqueous and serially purified latex extracts of plants Euphorbia pulcherima and Euphorbia hirta (family Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40 and 80% of LC₅₀) of aqueous and partially purified latex extracts of both the plants also significantly alter the levels of total protein, total free amino acid, nucleic acid (DNA and RNA) and the activity of enzyme protease and acid and alkaline phosphatase in nervous tissue of the snail Lymnaea acuminata in time and dose dependent manner. E. pulcherima and E. hirta are common medicinal plants of family Euphorbiaceae. E. pulcherima is useful for a variety of conditions, such as rheumatism, snakebite, asthma, obstipation, and skin-diseases. While, E. hirta is also used in cough, asthma, colic, dysentery, and genito urinary diseases.     

Molluscicides from some common medicinal plants of eastern Uttar Pradesh,India

Many aquatic snails act as intermediate hosts for the larvae of trematodes, Fasciola hepatica and Fasciola gigantica, which cause the diseases fascioliasis and schistosomiasis. The WHO has tested several thousands of synthetic compounds for the control of the snail host. Although effective, these molluscicides have so far not proved themselves to be entirely satisfactory. With a growing awareness of environmental pollution, efforts are being made to discover molluscicidal products of plant origin. Being products of biosynthesis, these are potentially biodegradable in nature. Several groups of compounds present in various plants have been found to be toxic to target organisms at acceptable doses ranging from <1 to 100 ppm. Common medicinal plants, i.e. Thevetia peruviana, Alstonia scholaris (Family; Apocynaceae), Euphorbia pulcherima and Euphorbia hirta (Family; Euphorbiaceae), have potent molluscicidal activity against freshwater snails. The toxicological actions of Thevetia peruviana may be due to the presence of apigenin‐5‐methyl ether (flavonoid) and triterpenoid glycosides, while a number of alkaloids (pseudo‐akuammigine in addition to betulin, ursolic acid and β‐sitosterol), steroids and triterpenoids are present in Alstonia scholaris and the diterpenoids, pulcherrol, β‐sitosterol, hentriacontane, ellagic acid and β‐amyrin are present in Euphorbia hirta and in Euphorbia pulcherima. Although, at present very little literature is available on the control of vector snails through plant origin pesticides, an attempt has been made in this review to assemble all the known information on molluscicidal properties of common medicinal plants of eastern Uttar Pradesh, India, which might be useful for the control of harmful snails. Copyright © 2009 John Wiley & Sons, Ltd.     

Molluscicidal properties of Acacia nilotica

The acetone, alcohol and aqueous extracts of fruits of Acacia nilotica (L) Willd. ex Del. (Mimosaceae) showed molluscicidal activity against Bulinus truncatus and Biomphalaria pfeifferi, the two snail species which transmit schistosomiasis in the Sudan (S. haematobium and S. mansonii). TAN, a new vegetable molluscicide prepared from the aqueous extract of the fruits of A. nilotica was produced on a pilot scale by using the spray drying procedure. Due to the high content of tannins in the powder (more than 56%), the molluscicidal properties of this plant may well be due to these compounds.     

Molluscicidal activity of Solanum elaeagnifolium seeds against Galba truncatula intermediate host of Fasciola hepatica: Identification of β-solamarine

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.     

Evaluation of the mutagenic potential of endod (Phytolacca dodecandra), a molluscicide of potential value for the control of schistosomiasis

Extracts of the fruit of Phytolacca dodecandra (endod) demonstrate molluscicidal and other biological activities. Since this plant is indigenous to some countries where schistosomiasis is a common problem, it has been proposed that it may be socioeconomically feasible to employ endod as an aid in the control of this disease through its use to control the snail vector. As an initial step in the safety assessment of this substance, its mutagenic potential was determined utilizing Salmonella typhimurium strain TM677. The seeds and fruit of Phytolacca americana, also molluscicidal, were additionally evaluated for mutagenic potential. Using a variety of conditions, no mutagenic activity could be demonstrated for any of the extracts tested. Thus, subject to the results of future safety assessment, endod remains a viable candidate as a useful molluscicide.     

O,O′-二烷基-O″-(取代苯乙腈肟)磷酸酯、硫代磷酸酯的合成及对氯硝柳胺的灭螺增效作用

合成了20个O,O′-二烷基-O″-(取代苯乙腈肟)磷酸酯、硫代磷酸酯,并分别与杀螺剂氯硝柳胺组成复方,进行室内杀螺试验。初步结果表明,化合物V_4,7,12,18有明显杀螺增效作用,其中V12可使氯硝柳胺的杀螺效果提高3.81倍。同时发现化合物V_2,7,10,13单独使用时,也有良好的杀螺作用。     

Molluscicidal and larvicidal activities and essential oil composition of Cymbopogon winterianus

Abstract

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.     

Synthesis of furo-salicylanilides and their heterocyclic derivatives with anticipated molluscicidal activity

The synthesis of new furo-salicylanilides and their heterocyclic derivatives is described. Twenty-three compounds were screened for their molluscicidal activity against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Five of the tested compounds showed no activity, while eighteen compounds showed strong to moderate activity using bayluscide as a reference.     

Screening for Protozoocidal Activity of Spanish Plants

Crude extracts of Spanish plants (60 representing 12 species from 7 families) have been screened for antiparasitic activity against Leishmania infantum and Trichomonas vaginalis. 30% of the extracts showed activity against one of the parasites and 15% of the extracts were active against both tests organisms. The most promising extracts originate from plants used in traditional medicine, such as Inula montana L. (Asteraceae), Bupleurum rigidum L. (Apiaceae) and Scrophularia scorodonia L. (Scrophulariaceae).     

Molluscicidal and antischistosomal activities of Zingiber officinale

Experiments were conducted to study the major constituents of Zingiber officinale responsible for its molluscicidal activity and the effect of the active component on different stages of Schistosoma mansoni. Gingerol and shogaol exhibited potent molluscicidal activity on Biomphalaria glabrata. Gingerol (5.0 ppm) completely abolished the infectivity of Schistosoma mansoni miracidia and cercariae in B. glabrata and mice, respectively, indicating that the molluscicide is capable of interrupting schistosome transmission at a concentration lower than its molluscicidal concentrations.     

Evaluation of oleoresin capsicum of Capsicum frutescenes var. Nagahari containing various percentages of capsaicinoids following inhalation as an active ingredient for tear gas munitions

Comparative efficacy as peripheral sensory irritant, oral and inhalation exposure studies were carried out on oleoresin capsicum (OC) of Capsicum frutescence var. Nagahari containing various percentages of capsaicinoids and two synthetic isomers of capsaicin in Swiss albino male mouse model to come up with a suitable active ingredient from natural source for tear gas munitions. The compounds screened were OC having varying percentages of capsaicinoids (20, 40 and 80%, respectively) and synthetic isomers (E and Z) of capsaicin (8-methyl-N-vanillyl-6-nonenamide). Mice were exposed to pyrotechnically generated smoke of the compounds in an all glass static exposure chamber for 15?min to determine acute inhalation toxicity (LC₅₀) and quantitative sensory irritation potential (RD₅₀). Acute oral median lethal dose (LD₅₀) was also evaluated. Safety index of tear gas (SITG), a ratio of lethal concentration 50% (LC₅₀) and the concentration which depresses respiration by 50% (RD₅₀) due to peripheral sensory irritation is also proposed. The compound having highest SITG is considered as the most suitable to be used for tear gas munitions. The study revealed that oleoresin capsicum containing 40% capsaicinoids had the highest SITG among the compounds studied. The oral dosage versus mortality pattern of some compoundsdid not follow a true dose–response curve (DRC); however, following inhalation, all the compounds followed DRC. It was concluded that oleoresin capsicum (40% capsaicinoids) may be considered as the most suitable and environmental friendly compound from natural source to be used as an active ingredient for tear gas munitions.     

Inhibition in vivo of the activity of botulinum neurotoxin A by small molecules selected by virtual screening

To search for small molecular size inhibitors of botulinum neurotoxin A (BoNT/A) endopeptidase activity, we have screened the NCI library containing about 1 million structures against the substrate binding pocket of BoNT/A. Virtual screening (VS) was performed with the software Glide (Grid-based ligand docking energetics) and the findings were confirmed by AutoDock. Ten compounds were found that had favorable energetic and glide criteria and 5 of these compounds were selected for their ability to protect mice in vivo against a lethal dose of BoNT/A. Each compound was incubated at different molar excesses with a lethal dose of the toxin and then the mixture injected intravenously into mice. At 4690 M excess, compounds NSC94520 and NSC99639 protected all (100%) the mice from lethal toxicity. Compounds NSC48461 and NSC627733 gave 75% protection. Compound NSC348884 showed the least inhibition of toxicity allowing only a fraction (25%) of the mice to survive challenge with a lethal dose; and in the case of the mice that did not survive there was a considerable delay of mortality. At 2400 M excess compounds NSC94520 remained fully protective while and NSC99639 afforded 75% protection and at 1200 M excess each of these two compounds gave 50% protection. The two compounds gave no protection at 600 or less molar excess. When each compound was administered intravenously at 4690 M excess at different times (from 1 h to 6 h) after the intravenous injection of the active toxin, none of the compounds was able to protect the animals from toxicity. The findings show the value of VS in identifying potential inhibitors of the toxin for further development and improvement.