Toxicity of the molluscicidal plant, Ambrosia maritima L., to aquatic non-target organisms

The toxicity of the molluscicidal plant, Ambrosia maritima L., has been evaluated in fish, crustacea and algae. The LC50 for fries of the guppy, Lebistes reticulatus, was respectively 650 and 450 mg/litre using a powder or an ether-methanol-hexane extract from the leaves of the plant. This concentration is much higher than the molluscicidal concentration (LC90) of 35 to 70 mg/litre, which is used in the field (irrigation canals in Egypt). Preliminary tests showed that juveniles of L. reticulatus and Tilapia aurea were as sensitive as the fries. Using the same extract of A. maritima the LC50 for Daphnia magna was 766 mg/litre and no toxic effects could be observed in algae Selenastrum capricornutum at 1 g/litre. It can be concluded that A. maritima has a very low toxicity to aquatic non-target organisms. It is not toxic when used at the molluscicidal concentration of 35 to 70 mg/litre.     

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.     

Molluscicidal constituents of Calophyllum from Madagascar: activity of some natural and synthetic neoflavonoids and khellactones.

Crude extracts of seeds, leaves and barks of four Madagascan Calophyllum species: C. inophyllum, C. recedens, C. chapelieri, and C. verticullatum, have been tested for molluscicidal activity against Biomphalaria glabrata. All seed extracts showed significant activity. The major constituents of the most active Calophyllum species were examined. Some related coumarinic derivatives were synthesized in order to improve the biological activity. Among the compounds prepared, 5,7-dihydroxy-6-(2-methylbutyryl)-4-phenyl-coumarin presented an interesting molluscicidal activity.     

Screening of European Fungi for Antibacterial,Antifungal, Larvicidal,Molluscicidal, Antioxidant and Free-Radical Scavenging Activities and Subsequent Isolation of Bioactive Compounds

Crude extracts of 57 species of European fungi have been tested for their bactericidal (Bacillus subtilis, Escherichia coli), fungicidal (Candida albicans, Cladosporium cucumerinum), larvicidal (Aedes aegypti), molluscicidal (Biomphalaria glabrata), antioxidant and free-radical scavenging activities. Connatine and 2(3,4-dihydroxyphenyl)glycine, two compounds with antioxidant and free-radical scavenging properties, were subsequently isolated from the methanolic extracts of Lyophyllum connatum (Tricholomataceae) and Cortinarius hercynicus (Cortinariaceae), respectively. In addition, linoleic acid was shown to be molluscicidal.     

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.     

Toxicity and mutagenicity of the molluscicidal plant Ambrosia maritima L.

The acute and subchronic toxicity of the molluscicidal plant, Ambrosia maritima L., has been tested on rats. No toxic signs could be detected neither after oral administration of 5 g/kg of dried leaves of the plant as a powder or as a methanolic extract, nor after the incorporation of 50,000 ppm powdered leaves in the feed during 4 weeks. Using an aqueous extract of the plant material of A. maritima or using ambrosin, one of the active molluscicidal components of the plant, no mutagenic activity could be detected in the S. typhimurium strains TA97, TA 98, TA1538, TA100 and TA1535.     

Cinnamoylnitrile-, pyran-, and pyranopyrazole-derivatives containing the salicylanilide moiety with anticipated molluscicidal activity.

The reaction of new cinnamonitriles containing the salicylyl moiety with active methylene reagents leads to the formation of the corresponding heterocycles. Their reaction with aniline yields the corresponding salicylanilide derivatives. The obtained pyrans and anilides were tested for molluscicidal activity.     

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.     

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 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).     

Antiviral, haemolytic and molluscicidal activities of triterpenoid saponins from Maesa lanceolata: establishment of structure-activity relationships

Ten saponins isolated from the leaves of Maesa lanceolata were tested for their antiviral, haemolytic and molluscicidal activities. The influence of the substitution pattern of these acylated triterpenoid saponins on their biological activities was investigated and structure-activity relationships were established. Maesasaponin VI(2) (3 beta-O-[[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-galactopyranosyl-(1 --> 3)]-[beta-D-galactopyranosyl-(1 --> 2)]-beta-D-glucopyranuronyl]-21 beta,22 alpha-diangeloyloxy-13 beta,28-epoxyolean-16 alpha,28 alpha-diol), the most potent molluscicidal compound (LC(50) 0.5 ppm), also showed virucidal and haemolytic activity. In general, 21,22-diacylation appeared to be associated with a virucidal (reduction factor of the viral titer > or = 10(3) at 50 microg/ml) and haemolytic activity (HC(50) < or = 1 microg/ml).     

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.     

Molluscicidal activity and clinico-pathological effect ofAgave lophantha

Dry powder and different extracts of Agave lophantha were tested against Biomphalaria alexandrina. The results showed that the butanol extract has high molluscicidal activity. The activity of the dry powder has been found to be stable under the effect of some simulated field conditions. Also the toxicological effect of the plant on mice was tested through determination of certain parameters such as total protein, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and acid phosphatase enzymes as well as histopathological study on liver and kidney.     

Molluscicidal and antifungal activity of diterpenoids from brown algae of the family dictyotaceae

17 diterpenoids isolated from brown algae of the family DICTYOTACEAE have been evaluated for molluscicidal and antifungal activity. Significant molluscicidal activity is exhibited by the two geometrical isomers 9 and 10. The assessment of structure-activity relationships has been considered.     

O,O′-二烷基-O″-(5-取代-3-苯并噻吩乙腈肟)磷酸酯及硫代磷酸酯的合成

合成了18个O,O′-二烷基-O″-(5-取代-3-苯并噻吩乙腈肟)磷酸酯及硫代磷酸酯类化合物(Ⅰ_1～18)。初步杀螺试验结果表明,其中5个化合物,即Ⅰ_2,3,7,11,12有明显的杀螺增效作用。     

Screening of plants used by North American indians for antifungal,bactericidal, larvicidal and molluscicidal activities

Nineteen plant species from fourteen families used in the traditional medicine of North American Indians have been tested for their fungicidal (Cladosporium cucumerinum, Candida albicans), bactericidal (Bacillus subtilis, Escherichia coli), larvicidal (Aedes aegypti) and molluscicidal (Biomphalaria glabrata) activities. Of the species investigated, 9 were active against Cladosporium cucumerinum, 9 against Candida albicans, 12 against Bacillus subtilis, 18 against Escherichia coli, 3 against Aedes aegypti, and 11 against Biomphalaria glabrata.     

Salicylamides Containing Amino Acid or Pyran Moieties with Molluscicidal Activity

Salicylamide amino acid conjugates were prepared utilizing 5-formyl-, 5-dicyanoethenyl-, and 5-nitroethenylsalicylic acid. 5-Substituted salicylanilides were treated with glycine and formaldehyde in a Mannich type reaction affording the corresponding 3-(N-glycino)salicylanilides. The reactions of anilines with pyrans containing the salicylyl moiety yielded the corresponding salicylanilides. The obtained compounds were tested for molluscicidal activity.     

Study of the Molluscicidal Activity of Some Phenolic Compounds: Structure-Activity Relationship

The relationship between the structure of 14 phenolic compounds and their molluscicidal activity against the molluscan intermediate host of urinary schistosomiasis, Bulinus truncatus, is discussed. It was found that among flavonoids tested, unhydroxylated flavone compound and flavanone hesperidin were the most active (LC₅₀ = 5.47 and 8.91 ppm, respectively), whereas gallic acid compound with para-methoxy group was the most effective among phenolic acids tested (LC₅₀ = 3.60 ppm). These results are encouraging and prove other biological application of these compounds.     

Molluskizid wirksame Spiro-α-methylen-γ-butyrolactone

α-Methylene-γ-butyrolactones with Molluscicidal Activity The α-methylene-γ-butyrolactones 1-28 were tested in vitro for molluscicidal activity against Biomphalaria glabrata. The racemic compound 25 shows the best activity. The synthesis was carried out by modified Reformatzky reaction of the corresponding carbonyl compounds and bromomethylacrylic acid ethyl ester. 7-10, 17 and 22-27 have been synthesized for the first time.     

Investigations of Molluscicidal Activity of Certain Sudanese Plants Used in Folk-Medicine. Part IV*

50 plants indigenous to the Sudan and of common use in Sudanese folk-medicine, were screened for their molluscicidal activity, using two local snail vectors, BULINUS TRUNCATUS and BIOMPHALARIA PFEIFFERI. At different concentrations 31 (62%) of these plant samples were found to be lethal to either one or both of the snail species. 28 (56%) proved to be lethal to BIOMPHALARIA PFEIFFERI, 22 (44%) gave 100% mortality to BULINUS TRUNCATUS; while 19 (38%) killed both snail hosts (Table I). The seven most active molluscicidal plants were phytochemically screened for their active constituents; four of them showed the presence of saponins.