Molluscicidal activity of Solanum elaeagnifolium seeds against Galba truncatula intermediate host of Fasciola hepatica: Identification of ß-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 ß-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, ß-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, ß-solamarine, and total saponins fraction may be used as molluscicides.

Comparative toxicity of Paraquat herbicide and some plant extracts in Lymnaea natalensis snails.

Paraquat has been shown to be a highly toxic compound for humans and animals, and many cases of acute poisoning and death have been reported over the past few decades. The present study was undertaken to evaluate comprehensively herbicides (Paraquat) and some plant extracts to biochemical aspects of Lymnaea natalensis snails. It was found that the exposure of L. natalensis to Paraquat and plant extracts led to a significant reduction in the infectivity of Fasciola gigantica miracidia to the snail. The glucose level in hemolymph of exposed snails was elevated, while the glycogen showed a decrease in soft tissues when compared with the control group. In addition, the activity level of some enzymes representing glycolytic enzymes as hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), and glucose phosphate isomerase (GPI) in snail's tissues were reduced in response to the treatment. It was concluded that the pollution of the aquatic environment by herbicide would adversely affect the metabolism of the L. natalensis snails. Snails treated with Agave attenuate, Ammi visnaga, and Canna iridiflora plant had less toxic effect compared to snails treated with Paraquat.

A bioactive prodelphinidin from Mangifera indica leaf extract.

A new trimeric proanthocyanidin, epigallocatechin-3-O-gallat-(4beta-->8)-epigallocatechin-(4beta-->8)-catechin (1), was isolated together with three known flavan-3-ols, catechin (2), epicatechin (3), and epigallocatechin (4), and three dimeric proanthocyanidins, 5-7, from the air-dried leaves of Mangifera indica. Their chemical structures were determined on the basis of 1D- and 2D-NMR spectra (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-mass spectra, and by acid-catalyzed degradation with phloroglucinol. The isolated compounds 1-7 were in vitro tested for their inhibitory activities against COX-1 and COX-2. Compound 1 was found to have a potent inhibitory effect on COX-2, while compounds 1 and 5-7 exhibited moderate inhibition against COX-1.

Alterations in carbohydrates and the protein metabolism of the harmful freshwater vector snail Lymnaea acuminata induced by the Euphorbia tirucalli latex extract.

To know the short- as well as long-term effect of aqueous latex extracts of Euphorbia tirucalli on carbohydrate and protein metabolism, the snail Lymnaea acuminata was exposed to sublethal doses of 0.37 and 0.55 mg/L for a 24-h and 0.20 and 0.31 mg/L for a 96-h exposure period. Significant (P<0.05) alterations in the glycogen, pyruvate, lactate, total protein, and free amino acid level, as well as in the activity of enzyme lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase, and alanine aminotransaminase were observed in the nervous, hepatopancreatic, and ovotestis tissues of the freshwater vector snail L. acuminata exposed to sublethal doses of E. tirucalli latex extract. The alterations in all biochemical parameters were significantly (P<0.05) time and dose dependent. After the 7th day of the withdrawal of treatment, there was significant (P<0.05) recovery in glycogen, pyruvate, lactate, total protein, and the free amino acid level and in the activity of the lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase and alanine aminotransaminase enzymes in all three of the studied tissues of the snail, which supports the view that the plant product is safe for use as a molluscicide for the control of harmful freshwater vector snails in the aquatic environment.

Toxicological effect and biochemical alterations induced by different fractions of Euphorbia royleana latex in freshwater harmful vector snail Lymnaea acuminata.

Laboratory evaluation was made to assess the molluscicidal activity of different fractions of Euphorbia royleana (Family- Euphorbiaceae) latex obtained through sephadex gel column against freshwater snail Lymnaea (Radix) acuminata Lamarack. This snail is the vector of liver fluke, Fasciola hepatica Linnaeus and Fasciola gigantica Cobbold, which causes endemic fascioliasis in cattle and livestock. The toxic effect of the different fractions was time dependent and fifth fraction obtained through benzene: ethyl acetate (5:5) had maximum molluscicidal activity against Lymnaea acuminata. There was a significant negative correlation between LC values and exposure periods thus increase in exposure time, the LC50 value of V fraction of Euphorbia royleana latex was decreased from 14.28 mg/l (24 hr) to 9.28 mg/l (96 hr) against Lymnaea acuminata. After exposure to sub-lethal concentrations of this fraction there were significant time and dose dependent alterations observed in pyruvate, lactate levels, ALAT, AAT, AChE and cytochrome oxidase enzyme activities in different body tissues of Lymnaea acuminata. It is proposed that the fifth fraction of E. royleana latex can be used as a molluscicide for controlling the harmful snail population from aquatic ecosystem without any harm due to their reversible toxic action.

Effect of molluscicidal components of Abrus precatorius, Argemone mexicana and Nerium indicum on certain biochemical parameters of Lymnaea acuminata.

Exposure to 40% and 80% of the 24 h LC50 of the molluscicidal component of Abrus precatorius (abrin and glycyrrhizin), Argemone mexicana (protopine and sanguinarine) and Nerium indicum (oleandrin) caused a significant decrease in the levels of protein, free amino acid, DNA and RNA in the nervous tissue of Lymnaea acuminata. Except for glycyrrhizin, all the above molluscicides caused a significant reduction in phospholipid levels and a simultaneous increase in the rate of lipid peroxidation in the nervous tissue of treated snails.

Studies on the molluscicidal actvity of Calendula micrantha officinalis (Compositae) on fascioliasis transmitting snails.

The molluscicidal activity of ethanolic extracts of Calendula m. officinalis (flowers and leaves) was used as plant molluscicides against Lymnaea cailliaudi. The results indicated that flowers extract possess a molluscicidal activity more than leaves extract and the LC50 was 35 and 52.17 ppm respectively. The mortality rate of exposed snails was increased by prolongation of the exposure time. The molluscicidal effect resulted in enhancing energy utilization and nutrient consumption since glucose, lipids, proteins and triglycerids were greatly reduced. The stomach and digestive gland of the treated L. cailliaudi snails were greatly altered.

The use of NO-sensitive microelectrodes for direct detection of nitric oxide (NO) production in molluscs.

The endogenous production of nitric oxide (NO) from the CNS and a peripheral sensory structure (osphradium) of the pulmonate molluscs, Lymnaea stagnalis and Limax sp. as well as from the rat aorta was studied using two different types of NO-sensitive microelectrodes. Both NO-sensitive electrodes gave complementary, but comparable results. From our data it was possible to compile a hierarchy of tissues with respect to estimated NO production: the rat aorta (300-600 nM) > Lymnaea osphradium (100-300 nM) > Lymnaea buccal ganglia (30-100 nM) > Limax protocerebrum (10-50 nM). In the preparations tested the administration of L-arginine (10 nM) caused an increased level of the recorded signals. This effect was suppressed by NG-Nitro-L-arginine (10 nM), an inhibitor of NOS. It may be concluded that NO can be detected directly from the CNS and peripheral tissues of Lymnaea, and rat aorta, despite the limitations of the techniques used. The putative level of NO production in the osphradium is higher than that in areas of the mammalian CNS and can be compared with release from the aorta. The NO release from the buccal ganglia and the protocerebrum was comparable with that of the rat cerebellum. Such high levels of NO production lend themselves to further analysis of the biological role of this molecule in molluscs.

cDNA cloning and deduced amino acid sequence of two ferritins: soma ferritin and yolk ferritin, from the snail Lymnaea stagnalis L.

Pulmonate freshwater snails contain two different ferritin types, soma ferritin and yolk ferritin. A cDNA library was constructed from midgut gland poly(A)-rich RNA of the snail Lymnaea stagnalis L. and recombinant clones encoding both ferritin types were obtained by immunoscreening. The longest cDNA inserts had a length of 859 bp (soma ferritin) and 1548 bp (yolk ferritin) and the specificity of these inserts was confirmed by immunoprecipitation of both ferritin types translated in vitro from hybrid-selected mRNAs. The 5' untranslated region (UTR) of the soma ferritin mRNA contains a 28-bp element which shows 64% sequence identity with the iron-responsive element (IRE) of vertebrate ferritin mRNAs. The soma ferritin mRNA is strongly translated in the wheat germ system but poorly translated in rabbit reticulocyte lysate. The yolk ferritin mRNA, which contains no IRE, is equally well translated in both in vitro translation systems. The deduced amino acid sequence of the soma ferritin subunit (174 amino acid residues, M(r) 20140) shows 50-70% sequence identity with subunits of vertebrate ferritins. After removal of an 18-amino-acid-residue signal sequence the deduced protein sequence of yolk ferritin contains 221 amino acids (M(r) 25438). Sequence identity of this chain with other eukaryotic ferritin chains is only 31-42%. Both snail ferritin sequences are more similar to the H-subunit type of vertebrate ferritins than to the L-type and both have the H-specific amino acid residues of the ferroxidase centre. The yolk ferritin sequence has a 42-amino-acid-residue insertion predicted to reside in the L loop of the subunit.

The uptake and distribution of radioselenium in the larvae of Fasciola hepatica and its snail host Lymnaea columella.

Radiolabeled metacercariae of Fasciola hepatica were obtained in vivo by incubating infected Lymnaea columella snails with 20 muCi radioselenomethione (75Se-M) per snail in 5 ml of water for 5 h, or in vitro by incubating a batch of unlabeled F. hepatica metacercariae with 75Se-M for 24 h. Radioassay showed that only 5% of the 75Se-M was incorporated into maritas (juvenile flukes) from the in vivo labeled metacercariae. The inner cyst wall of in vivo labeled metacercariae contained 46% of the total activity, of which 21% was dissolved in the excysting medium. The outer, tan-colored cyst wall contained 49% of the radioactivity. Through diffusion/attachment, maritas from in vitro labeled metacercariae could occasionally be labeled with 0.4% of the total radioactivity. However, the activity was lost after inoculation into the body of mice. The outer and inner cyst walls of in vitro labeled metacercariae contained 92% and 7.6%, respectively, of the total activity. Microautoradiography demonstrated that 75Se-M was evenly distributed in the body of marita and the cyst wall of inner and outer layers from an in vivo labeled metacercaria. A 9 X 4 micron rectangularly-shaped aggregate of Ag degree grains was present on the outer periphery of the inner cyst wall. Microautoradiography of in vitro labeled metacercariae demonstrated a significant concentration of Ag degree grains on the cyst walls. The ventral plug contained fewer Ag degree grains per unit area compared to the other portion of the inner cyst wall. Uptake and distribution of 75Se-M in the snail host were also studied. It appeared that rediae and cercariae tended to concentrate the label in the foot, the mantle and the digestive gland. Little or no radioactivity was present in the areas where F. hepatica larvae were not found.

[Characteristics of plastic metabolism and inorganic phosphorus absorption in Lymnaea stagnalis L. in prolonged exposure to a toxic agent]. / Osobennosti plasticheskogo obmena i pogloshcheniia neorganicheskogo fosfora u Lymnaea stagnalis L. pri dlitel'nom vozdeistvii toksikanta.

The influence of fungicide trimethyltinchloride upon the metabolism and K2H32PO4 uptake in Limnaea stagnalis L. in the process of its growth has been examined. The mollusks sensitivity of the different age groups to the toxic effect of this compound are determined.