RESUMEN
Nematode infections affect a fifth of the human population, livestock, and crops worldwide, imposing a burden to global public health and economies, particularly in developing nations. Resistance to commercial anthelmintics has increased over the years in livestock infections and driven the pursuit for new drugs. We herein present a rapid, cost-effective, and automated assay for nematicide discovery using the free-living nematode Caenorhabditis elegans to screen a highly diverse natural product library enriched in bioactive molecules. Screening of 10,240 fractions obtained from extracts of various biological sources allowed the identification of 7 promising hit fractions, all from marine sponges. These fractions were further assayed for nematicidal activity against the sheep nematode parasite Haemonchus contortus and for innocuity in zebrafish. The most active extracts against parasites and innocuous toward vertebrates belong to two chemotypes. High-performance liquid chromatography (HPLC) coupled with nuclear magnetic resonance (NMR) revealed that the most abundant compound in one chemotype is halaminol A, an aminoalcohol previously identified in a small screen against H. contortus. Terpene-nucleotide hybrids known as agelasines predominate in the other chemotype. This study reinforces the power of C. elegans for nematicide discovery from large collections and the potential of the chemical diversity derived from marine invertebrate biota.
Asunto(s)
Antinematodos , Caenorhabditis elegans , Poríferos , Animales , Poríferos/química , Antinematodos/farmacología , Antinematodos/química , Caenorhabditis elegans/efectos de los fármacos , Estructura Molecular , Pez Cebra , Haemonchus/efectos de los fármacos , Cromatografía Líquida de Alta Presión/métodosRESUMEN
Biological control using edible mushrooms as natural enemies is a sustainable alternative for pest management. Despite the well-established literature on toxins and secondary metabolites produced by these fungi in the biochemical control of nematodes, the nematicidal activity of proteases from different Pleurotus species is yet to be investigated. Therefore, this study aimed to correlate protease to the nematicidal activity of different mushrooms, Pleurotus sp., P. ostreatus (SB), P. ostreatus (Pearl), and P. djamor. For such a purpose, we performed motility assays of Panagrellus sp. at different time intervals, 6, 12, and 24 h for each of the mushrooms. In addition, the protease activity was measured using different pH (5, 7, and 9) and fermentation time intervals (45 and 75 days). Furthermore, we also evaluated the effect of this cell-free extract on Panagrellus sp. In response to these experiments, all edible mushrooms showed a reduction over 82% for the nematode-feeding activity (p < 0.01). The cell-free crude extract of each of the fungi studied showed nematocidal activity (p < 0.01). For the 45-day fermentation, P. djamor exhibited statistical significance (p < 0.01) compared with the others, reaching a reduction percentage of 73%. For the 75-day fermentation, Pleurotus sp. and P. ostreatus (Pearl) showed significant differences compared with the other fungi (p < 0.01), with reduction percentages of 64 and 62%, respectively. Herein, protease activity was associated with the nematicidal action of different Pleurotus species in controlling Panagrellus sp.
Asunto(s)
Agaricales , Pleurotus , Proteolisis , Antinematodos/farmacología , Péptido Hidrolasas , EndopeptidasasRESUMEN
The demand for new soil fumigants has increased as a result of more restrictive legislation regarding the use of pesticides. In the present study, the potent nematicidal activity of volatile organic compounds released by the Annona muricata leaf macerate was demonstrated. In addition, we searched in the A. muricata volatilome for a molecule with potential to be developed as a new fumigant nematicide. In the greenhouse, even the lowest concentration of soursop leaf macerate tested (1.0%) as a biofumigant caused a significant (P < 0.05) reduction in Meloidogyne incognita infectivity and reproduction when compared with the nontreated control (0%). Forty-one compounds were identified through gas chromatography-mass spectrometry analysis, of which three (sabinene, caryophyllene oxide, and 4-ethylbenzaldehyde) were selected for studies against the nematode. Among these compounds, in in vitro trails, only 4-ethylbenzaldehyde showed nematicidal activity at 250 µg ml-1. The effective doses of 4-ethylbenzaldehyde predicted to kill 50 and 95% of the M. incognita second-stage juvenile population after 48 h of exposure were 35 and 88 µg ml-1, respectively. In in vitro tests, 4-ethylbenzaldehyde at 150 µg ml-1 reduced M. incognita egg hatching to values similar (P > 0.05) to those of the commercial nematicide fluensulfone at a concentration of 200 µg ml-1. In plant experiments, as a soil fumigant, 4-ethylbenzaldehyde at a dose of 1 ml/liter of substrate had an effect similar (P > 0.05) to that of the commercial fumigant Dazomet (250 µg ml-1). Therefore, 4-ethylbenzaldehyde shows potential for development as a new nematicide.
Asunto(s)
Annona , Plaguicidas , Tylenchoidea , Animales , Antinematodos/farmacología , Antinematodos/química , Plaguicidas/farmacología , Suelo/químicaRESUMEN
PURPOSE: In the present study, the nematicidal activity of the chemical fractionation of the spent substrate of the edible mushroom Pleurotus ostreatus against eggs and L3 larvae of Haemonchus contortus was evaluated. METHODS: The hydroalcoholic extract of the spent substrate was subjected to a bipartition with ethyl acetate giving two fractions: one aqueous (F. Ac) and one organic (F. AcOET). Both fractions were evaluated against eggs and L3 larvae at different concentrations (5, 2.5, 1.25, 0.625 and 0.3125 mg/mL) and 2% methanol, PBS and thiabendazole (5 mg/mL) as controls. Chemical fractionation of F. AcOET was performed in open column chromatography where 76 fractions were obtained and when analyzed by thin layer chromatography (TLC) were grouped into 11 mixtures (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11). These mixtures were evaluated at 10 mg/mL against eggs and L3 larvae. The data obtained were analyzed by ANOVA and a Tukey test in the SAS V9 program. RESULTS: The results showed that, in the evaluation of F. AcOET and F. Ac, for the inhibition of egg hatching, the highest percentages were 78.80 and 76.89% at 5 mg/mL, respectively. As for the percentage of larval mortality, F. AcOET obtained 60.91 and F. Ac 29.77% at 5 mg/mL. The results of the evaluations of the mixtures showed that mixtures R4, R5 obtained 100 and 95.41% larval mortality and mixtures R6 and R7 presented 100% inhibitory activity of egg hatching, so these were analyzed by gas chromatography mass spectrometry finding compounds such as vanillin, ß-sitosterol, ρ-methyl ρ-hydroxycinnamate and ρ-hydroxybenzaldehyde. CONCLUSION: The results of the present study demonstrate that the spent substrate of P. ostreatus has potential anthelmintic activity against H. contortus. Moreover, by reusing and taking advantage of this substrate, its environmental pollution effects can be reduced.
Asunto(s)
Antihelmínticos , Haemonchus , Pleurotus , Animales , Extractos Vegetales/farmacología , Antinematodos/farmacología , Antihelmínticos/farmacología , Antihelmínticos/química , LarvaRESUMEN
To contribute to the development of new fumigant nematicides for the control of the plant-parasitic nematode Meloidogyne incognita, this study started with 31 volatile organic compounds reported as toxic to nematodes. At 500 µg/mL, α-ionone, (S)-carvone, (R)-carvone, 2-methylpropyl acetate, undecan-2-one, decan-2-one, and dodecan-2-one caused mortalities to M. incognita second-stage juveniles (J2) that were similar to those obtained with the commercial nematicides carbofuran (170 µg/mL) and fluensulfone (42.2 µg/mL). (R)-carvone, with a lethal concentration to 50% J2 (LC50) equal to 524 µg/mL, was selected for subsequent studies. When J2 were exposed to the (R)-carvone solution, the infectivity and reproduction on tomato were reduced. In the M. incognita egg hatching assay, (R)-carvone behaved like a true ovicide. When employed as a fumigant, (R)-carvone (3.9 g/L) was as efficient as the soil fumigant dazomet (0.245 g/L) in eliminating eggs of the nematode in a substrate to be used for tomato planting. According to in silico studies employing pharmacophoric searches and molecular docking, acetylcholinesterases are the target of (R)-carvone in the nematode.
Asunto(s)
Solanum lycopersicum , Tylenchoidea , Acetilcolinesterasa , Animales , Antinematodos/química , Antinematodos/farmacología , Monoterpenos Ciclohexánicos , Solanum lycopersicum/parasitología , Simulación del Acoplamiento Molecular , SueloRESUMEN
Nacobbus celatus sp. n. is one of the main root-knot nematodes in the field destined for horticultural production of the central region of Argentine due to its ability to infect several host plants. The lack of new and safe active ingredients against this nematode has restricted control alternatives for growers. Egg-parasitic fungi and biofumigation with brassicaceae have been considered as potential candidates for the development of bionematicides. Nematicidal effects of Brassica oleracea var. italica (broccoli) and Brassica oleracea var. capitata (cabbage) aqueous extracts (AEs) against second-stage juveniles (J2) of N. celatus were evaluated in vitro. Fisher LSD tests evidenced significant nematicidal (α = 0.05) effects of the two AEs tested, with LD100 of 250 and 500 µL mL-1 for broccoli and cabbage, respectively. Compatibility assays between AEs and five nematophagous fungi were performed on soil extract medium conditioned at 0.99 water activity and incubated at 30, 25 and 20 °C. Purpureocillium lilacinum SR14 was the fungal strain that showed compatibility at levels of spore viability, growth rate and conidia productions at LD50 (125 µL mL-1) and LD25 (60 µL mL-1) of broccoli aqueous extract (BAE) and enhanced the nematophagous effect. Moreover, phytotoxic studies revealed that 125 µL mL-1 of BAE applied at the transplantation time could be safely used without affecting tomato culture. In conclusion, the integrated application of BAE with P. lilacinum SR14, which combines two action mechanisms, represents a promising integrated strategy to management phytoparasitic nematodes.
Asunto(s)
Brassica , Solanum lycopersicum , Tylenchoidea , Animales , Antinematodos/farmacología , HongosRESUMEN
(E)-Cinnamaldehyde is very active against Meloidogyne incognita but has low persistence in soil. To circumvent this problem, esters of cinnamic acid were evaluated as a substitute for (E)-cinnamaldehyde. The best results under assays with M. incognita second-stage juveniles (J2) were obtained for the methyl esters of (E)-p-fluoro- (13), (E)-p-chloro- (14), and (E)-p-bromocinnamic acid (15), which showed lethal concentrations to 50% (LC50) J2 of 168, 95, and 216 µg/mL, respectively. Under the same conditions, the LC50 values for the nematicides carbofuran and fluensulfone were 160 and 34 µg/mL, respectively. Substances 13-15 were also active against nematode eggs, which account for most of the M. incognita population in the field. According to an in silico study, substances 13-15 can act against the nematode through inhibition of histone deacetylase. Therefore, esters 13-15 and histone deacetylase are potentially useful for the rational design of new nematicides for the control of M. incognita.
Asunto(s)
Tylenchoidea , Animales , Antinematodos/farmacología , Cinamatos , Ésteres/farmacología , Histona DesacetilasasRESUMEN
A recent screen of 67,012 compounds identified a new family of compounds with excellent nematicidal activity: the ortho-substituted benzamide families Wact-11 and Wact-12. These compounds are active against Caenorhabditis elegans and parasitic nematodes by selectively inhibiting nematode complex II, and they display low toxicity in mammalian cells and vertebrate organisms. Although a big number of benzamides were tested against C. elegans in high-throughput screens, bioisosteres of the amide moiety were not represented in the chemical space examined. We thus identified an opportunity for the design, synthesis and evaluation of novel compounds, using bioisosteric replacements of the amide group present in benzamides. The compound Wact-11 was used as the reference scaffold to prepare a set of bioisosteres to be evaluated against C. elegans. Eight types of amide replacement were selected, including ester, thioamide, selenoamide, sulfonamide, alkyl thio- and oxo-amides, urea and triazole. The results allowed us to perform a structure-activity relationship, highlighting the relevance of the amide group for nematicide activity. Experimental evidence was complemented with in silico structural studies over a C. elegans complex II model as a molecular target of benzamides. Importantly, compound Wact-11 was active against the flatworm Echinococcus granulosus, suggesting a previously unreported pan-anthelmintic potential for benzamides.
Asunto(s)
Antihelmínticos , Caenorhabditis elegans , Amidas , Animales , Antihelmínticos/química , Antihelmínticos/farmacología , Antinematodos/farmacología , Benzamidas/farmacología , MamíferosRESUMEN
BACKGROUND: Helminthiasis and resistance to commercial anthelmintic compounds are major causes of economic losses for livestock producers, resulting in an urgent need for new drugs and reliable in vitro screening tests capable of detecting potentially active products. Considering this, a series of novel benzimidazole derivatives (5-methylbenzimidazole 1,2-disubstituted, 5-carboxybenzimidazole, 5-methylbenzimidazole 2-one) was screened on exsheathed L3 (xL3) and on the adult stage of Haemonchus contortus (Kirby anthelmintic-susceptible McMaster isolate). METHODS: This work presents the set-up of an automated motility assay on the xL3 stage of H. contortus using an infrared tracking device (WMicrotracker One) together with a larval development test (xL3 to L4) and a motility assay on the adult stage of H. contortus. A comparative study of the sensitivity of these in vitro assays using commercial anthelmintics with different mechanisms of action was carried out, also evaluating anthelmintic activity of a series of novel benzimidazole derivatives. RESULTS: The automated xL3 assay had the great advantage of being able to analyze many compounds simultaneously, but it showed the limitation of having lower sensitivity, requiring higher concentrations of the commercial anthelmintics tested compared to those needed for the adult motility or development assays. Although none of the novel 1,2,5-tri-substituted benzimidazole derivatives could significantly decrease the motility of xL3s, one of them (1e) significantly affected the development of xL3s to L4, and five new compounds (1b, 1d, 1e, 2a and 2c) reduced the motility of H. contortus adult stage. CONCLUSIONS: The analysis of the results strongly suggests that the in vitro xL3 to L4 development test, particularly for the L4 stage, could be closer to the pharmacological sensitivity of the adult stage of H. contortus (target of interest) for commercial anthelmintic selected, with different mechanisms of action, and for the series of benzimidazole derivatives assayed. Therefore, an automated motility assay on L4 using the infrared tracking device is being set up. Further studies will be conducted to evaluate the in vivo anthelmintic activity of the most active novel benzimidazole derivatives.
Asunto(s)
Antihelmínticos , Haemonchus , Animales , Antihelmínticos/farmacología , Antinematodos/farmacología , Bioensayo , Técnicas In Vitro , LarvaRESUMEN
In the present study, the nematicidal activity of a Moringa oleifera ethyl acetate leaf extract against the eggs and larvae of Haemonchus contortus and Nacobbus aberrans, nematodes of agricultural importance, was evaluated. The experimental design for the evaluation of the effects against both nematodes consisted of eight treatments (n = 4). Distilled water, Tween (4%) and a commercial anthelmintic agent (ivermectin, 5 mg/mL) were used as controls, and for treatments 4-8, the concentrations of the extract were 20, 10, 5, 2.5 and 1.25 mg/mL, respectively. Readings were taken at 12 h and 24 h for N. aberrans and 48 h and 72 h for H. contortus post-treatment under an optical microscope (10× and 40×). The data obtained were analysed by analysis of variance through a completely randomized factorial design using the SAS V9 program. The results show that, for H. contortus egg hatching, 85.88% inhibition was obtained at a concentration of 20 mg/mL at 48 h, while for third-stage larva (L3) mortality, the highest percentage was 68.19% at 1.25 mg/mL at 72 h. In the case of N. aberrans, the greatest inhibition of egg hatching was 90.69% at 5 mg/mL at 12 h post-treatment, and for larval mortality, it was 100% at 10 mg/mL at 24 h post-treatment. The main major compounds identified by qualitative analysis and by gas chromatography coupled to mass spectrometry were 9,12,15-octadecatrienoic acid, (Z,Z,Z)-, n-hexadecanoic acid and 2,4-di-tert-butylphenol, and the minor compounds included phytol, γ-sitosterol and α-tocopheryl acetate. It was demonstrated that the ethyl acetate leaf extract of M. oleifera Lam. shows great potential for combating agricultural nematodes.
Asunto(s)
Antihelmínticos , Haemonchus , Moringa oleifera , Animales , Antihelmínticos/farmacología , Antinematodos/farmacología , Cromatografía de Gases y Espectrometría de Masas , Larva , Extractos Vegetales/química , Extractos Vegetales/farmacologíaRESUMEN
AIM: This study was designed to investigate if culturing nematophagous fungi (NF) in the presence of a Haemonchus contortus larva crude extract (HcCE) enhances the nematocidal activity of nematophagous fungi liquid culture filtrates (NFCF). MATERIALS AND METHODS: Four NF Arthrobotrys oligospora, A. musiformis, Duddingtonia flagrans and Clonostachys rosea were cultured in flasks (n = 5) containing Czapek-Dox broth medium (CDB) in the presence or absence of HcCE. NFCF recovered by filtration of each fungus (200 mg/mL) were assessed on H. contortus infective larvae (L3) using 96-well micro-titer plates (n = 4). Additionally, CDB and water were considered negative controls, while Ivermectin acted as a positive control. After 48 h confrontation, ten 10-µL aliquots of each well were deposited on slides and observed under the microscope (40 ×). Dead and alive larvae in the aliquots were quantified, and a mortality rate (MR) was estimated. RESULTS: The MR of the different NFCF was greatly enhanced by the presence of HcCE. The four NF incubated in the absence of HcCE showed low mortality percentages from 8.2 to 25.8%; in contrast, when the assessed NF growth in the presence of HcCE showed a lethal activity ranging from 66.8 to 80.5%. Only C. rosea showed a moderate increase in the presence of the elicitor (42.7%). CONCLUSION: This study shows evidence about the HcCE enhances the production of nematocidal activity in NFCF. Future studies should be performed to elucidate the compounds responsible of the nematocidal activity that could have important implications in the control of sheep haemonchosis.
Asunto(s)
Haemonchus , Nematodos , Trichostrongyloidea , Animales , Antinematodos/farmacología , Mezclas Complejas , Heces , Haemonchus/microbiología , Larva/microbiología , Control Biológico de Vectores , OvinosRESUMEN
Root-knot nematodes (RKN) are sedentary parasites of the roots of plants and are considered some of the most damaging pests in agriculture. Since RKN target the root vascular system, they provoke host nutrient deprivation and defective water transport, causing above-ground symptoms of growth stunting, wilting, chlorosis, and reduced crop yields. In Mexico RKN infestations are primarily dealt with by treating with synthetic chemically based nematicides that are preferred by farmers over available bioproducts. However, due to environmental and human health concerns chemical control is increasingly restricted. Biological control of RKNs can help reduce the use of chemical nematicides as it is achieved with antagonistic organisms, mainly bacteria, fungi, other nematodes, or consortia of diverse microorganisms, which control nematodes directly by predation and parasitism at different stages: eggs, juveniles, or adults; or indirectly by the action of toxic diffusible inhibitory metabolites. The need to increase agricultural production and reduce negative environmental impact creates an opportunity for optimizing biological control agents to suppress nematode populations, but this endeavour remains challenging as researchers around the world try to understand diverse control mechanisms, nematode and microbe life cycles, ecology, metabolite production, predatory behaviours, molecular and biochemical interactions, in order to generate attractive products with the approval of local regulatory bodies. Here, we provide a brief review of the biology of the genus Meloidogyne, biological control strategies, and a comparison between chemical and bioproducts in the Mexican market, and guidelines emitted by national agencies to ensure safety and effectiveness of new developments.
Asunto(s)
Agricultura , Antinematodos/farmacología , Agentes de Control Biológico , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/terapia , Tylenchoidea/fisiología , Animales , Bacterias , Hongos , Estadios del Ciclo de Vida , México , Raíces de Plantas/microbiología , Raíces de Plantas/parasitologíaRESUMEN
The objective of this study was to assay the ovicidal and larvicidal effects of two hydroalcoholic extracts (HA-E) and their aqueous fractions (Aq-F) and organic fractions (EtOAc-F) from Lippia graveolens (leaves) and Delonix regia (flowers) against the parasitic nematode Haemonchus contortus. The egg hatching inhibition test (% EHI) and mortality of infective larvae (% mortality) were used as biological models. The treatments of each plant (mg/mL, % EHI, and % mortality) were assigned as follows: HA-E (12.5-50, EHI; 25-200, mortality), Aq-F (6.25-25.00, EHI; 12.5-50, mortality), EtOAc-F (0.37-25, EHI; 3.12-50, mortality), negative controls (distilled water and methanol at 2% and 4%), and positive control (ivermectin at 5 mg/mL). Data were analyzed using a completely randomized design through an analysis of variance, considering the EHI and mortality percentages as the response variables. To identify the secondary metabolites, both plants were subjected to qualitative chemical analysis and HPLC. The results showed that both plants exhibited highly ovicidal and larvicidal effects. The bipartition in each HA extract allowed the increase of the anthelmintic effect in EtOAc-F, achieving a total ovicidal activity at 1.56 mg/mL and a larvicidal effect higher than 90% at 25 mg/mL. The qualitative chemical profile of both vegetal species identified alkaloids, flavonoids, condensed tannins, terpenes, and saponins. These results suggest that either L. graveolens leaves or D. regia flowers could be potential candidates for the control of parasitic gastrointestinal nematodes in small ruminants. However, in vivo studies with experimental animals to evaluate their possible toxicity and anthelmintic effect are necessary.
Asunto(s)
Fabaceae , Haemonchus , Lippia , Animales , Antinematodos/farmacología , Flores , Larva , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la PlantaRESUMEN
The objective of this study was to evaluate and compare the in vitro lethal effect of the hydroalcoholic extract of the spent substrate of Pleurotus djamor ECS-123, obtained at 15 days of colonization (SPS) and at the first (SPS1) and second (SPS2) harvests, against infective larvae L3 of Haemonchus contortus. The in vitro lethal effect was evaluated by the L3 larval mortality test (LM) using six concentrations: 1.25, 2.5, 5, 10, 20, and 40 mg/mL, with ivermectin and thiabendazole (5 mg/mL) as controls. The first harvest extract (SPS1) of strain ECS-123 was subjected to liquid-liquid bipartition, which resulted in two fractions: aqueous (PdAcO) and ethyl acetate (PdAct). The chemical fractionation of PdAct with the highest mortality rate (80.11 %) was carried out with open-column chromatography, giving a total of 13 fractions, which were analyzed by thin-layer chromatography (TLC) and grouped into 5 mixtures (R1;1-3, R2;4-7, R3;8-9, R4;10-11 and R5;12-13). Subsequently, the mixtures were evaluated against H. contortus L3 larvae. Finally, the components of the mixtures with the highest nematocidal effects were evaluated by gas chromatography coupled to mass spectrometry (GC-MS). The data were analyzed with a completely randomized design through ANOVA using the generalized linear model (GLM) with the "R" program. The purification and characterization of R4 and R5 by GC-MS revealed the presence of the following compounds: veratryl alcohol, 4-hydroxy-3,5,5 trimethyl-4-[3-oxo-1-butenyl]-2- cyclohexen-1-one, caffeine and 5,6-dimethoxy-1(3 H) isobenzofuranone. This information allowed for the identification of nematocidal compounds in the degraded substrate of P. djamor, an activity that had not been reported previously.
Asunto(s)
Antihelmínticos , Haemonchus , Animales , Antihelmínticos/farmacología , Antinematodos/farmacología , Antinematodos/uso terapéutico , Larva , Extractos Vegetales/farmacología , PleurotusRESUMEN
Root-knot nematodes cause damage to several crops and the importance of each species can vary according with the crop and the agricultural region. In Brazil, Meloidogyne javanica is one of the most important nematode species parasitizing mulberry. To define management strategies, it is important to know if the crop species is damaged by the parasitism of the nematode and the best choices for control, as the use of nematicides. Biological nematicides have been extensively used in Brazil, but no information regarding its efficiency to control M. javanica in mulberry is available. Besides, it is not known if biological nematicides could improve the quality of leaves or if they alter the nutrient composition of leaves, which could interfere in the development of the silkworms that are feed with these leaves or in the quality of the silk produced. With the aim to address these questions, we propose a study that will start in the phenotyping of the main Brazilian mulberry cultivars to Meloidogyne species, passing through the test of efficiency of biological nematicides in the control of M. javanica in mulberry cultivar Miura, evaluation of the amount and quality of leaves produced and, using these leaves to feed silkworms, in the analyzes of the impact of these diet in the health of silkworms, and in the production and quality of the silk.
Asunto(s)
Antinematodos/farmacología , Bombyx/crecimiento & desarrollo , Interacciones Huésped-Parásitos , Morus/crecimiento & desarrollo , Hojas de la Planta/crecimiento & desarrollo , Seda/fisiología , Tylenchoidea/fisiología , Animales , Morus/efectos de los fármacos , Morus/parasitología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/parasitología , Seda/efectos de los fármacos , Tylenchoidea/efectos de los fármacosRESUMEN
Nacobbus aberrans ranks among the "top ten" plant-parasitic nematodes of phytosanitary importance. It causes significant losses in commercial interest crops in America and is a potential risk in the European Union. The nematicidal and phytotoxic activities of seven plant extracts against N. aberrans and Solanum lycopersicum were evaluated in vitro, respectively. The chemical nature of three nematicidal extracts (EC50,48h ≤ 113 µg mL-1) was studied through NMR analysis. Plant extracts showed nematicidal activity on second-stage juveniles (J2): (≥87%) at 1000 µg mL-1 after 72 h, and their EC50 values were 71.4-468.1 and 31.5-299.8 µg mL-1 after 24 and 48 h, respectively. Extracts with the best nematicidal potential (EC50,48h < 113 µg mL-1) were those from Adenophyllum aurantium, Alloispermum integrifolium, and Tournefortia densiflora, which inhibited L. esculentum seed growth by 100% at 20 µg mL-1. Stigmasterol (1), ß-sitosterol (2), and α-terthienyl (3) were identified from A. aurantium, while 1, 2, lutein (4), centaurin (5), patuletin-7-ß-O-glucoside (6), pendulin (7), and penduletin (8) were identified from A. integrifolium. From T. densiflora extract, allantoin (9), 9-O-angeloyl-retronecine (10), and its N-oxide (11) were identified. The present research is the first to report the effect of T. densiflora, A. integrifolium, and A. aurantium against N. aberrans and chemically characterized nematicidal extracts that may provide alternative sources of botanical nematicides.
Asunto(s)
Antinematodos/farmacología , Extractos Vegetales/química , Extractos Vegetales/toxicidad , Solanum lycopersicum/efectos de los fármacos , Animales , Antinematodos/química , Espectroscopía de Resonancia Magnética con Carbono-13 , Espectroscopía de Protones por Resonancia Magnética , Tylenchoidea/efectos de los fármacosRESUMEN
PURPOSE: (1) To assess the in vitro activity of Artemisia cina against Haemonchus contortus L3 (HcL3) and in transitional (L3-L4) larvae (HcTrL3-L4); (2) to quantify the relative expression of the Hc29 gene in HcTrL3-L4 exposed to the A. cina n-hexane extract; and (3) to assess the anthelmintic activity (AA) of the A. cina organic extracts in gerbils artificially infected with H. contortus (HcArt/inf/gerbs). METHODS: The in vitro assay was carried out in 96-well microtitration plates. The following A. cina extracts: ethyl acetate (Ac-EtOAcEx), n-hexane (Ac-n-HexEx), and methanol (Ac-MethEx) were assessed at 1 and 2 mg/mL against HcL3 and HcTrL3-L4 at 24 h exposure. Relative expression of the Hc29 gene in HcTrL3-L4 was obtained by RT-PCR. For assessing the AA, six groups of five HcArt/inf/gerbs were used. Groups were treated orally with 4 mg/kg BW of A. cina extracts. Five days after treatment, the gerbils were necropsied and nematodes counted. RESULTS: The highest in vitro activities (75 and 82.6%) were shown by Ac-n-HexEx at 1 and 2 mg/mL, respectively. For HcTrL3-L4 the highest in vitro activities (69 and 23%) were shown by Ac-n-HexEx and isoguaiacine at 0.625 mg/mL, respectively. Also, upregulation of H. contortus Hc29 gene by 13- and 80-fold (p < 0.01) was observed on the HcTrL3-L4 stage after exposure to Ac-n-HexEx extract and isoguaiacine at 0.078 mg/mL, respectively. Reduction percentage was 100% in HcArt/inf/gerbs treated with Ac-n-HexEx. CONCLUSIONS: We conclude that the Ac-n-HexEx and isoguaiacine compound had anthelmintic efficacy against H. contortus and L3 and HcTrL3-L4.
Asunto(s)
Antihelmínticos , Artemisia , Hemoncosis , Haemonchus , Animales , Antihelmínticos/farmacología , Antihelmínticos/uso terapéutico , Antinematodos/farmacología , Antinematodos/uso terapéutico , Gerbillinae , Hemoncosis/tratamiento farmacológico , Hemoncosis/veterinaria , Haemonchus/genética , Larva , Extractos Vegetales/farmacologíaRESUMEN
BACKGROUND: Infection by nematodes is a problem for human health, livestock, and agriculture, as it causes deficits in host health, increases production costs, and incurs a reduced food supply. The control of these parasites is usually done using anthelmintics, which, in most cases, have not been fully effective. Therefore, the search for new molecules with anthelmintic potential is necessary. METHODS: In the present study, we isolated and characterized molecules from the nematophagous fungus Pochonia chlamydosporia and tested these compounds on three nematodes: Caenorhabditis elegans; Ancylostoma ceylanicum; and Ascaris suum. RESULTS: The ethyl acetate extract showed nematicidal activity on the nematode model C. elegans. We identified the major substance present in two sub-fractions of this extract as ketamine. Then, we tested this compound on C. elegans and the parasites A. ceylanicum and A. suum using hamsters and mice as hosts, respectively. We did not find a difference between the animal groups when considering the number of worms recovered from the intestines of animals treated with ketamine (6 mg) and albendazole (P > 0.05). The parasite burden of larvae recovered from the lungs of mice treated with ketamine was similar to those treated with ivermectin. CONCLUSIONS: The results presented here demonstrate the nematicidal activity of ketamine in vitro and in vivo, thus confirming the nematicidal potential of the molecule present in the fungus P. chlamydosporia may consist of a new method of controlling parasites.
Asunto(s)
Hypocreales/metabolismo , Ketamina , Nematodos , Albendazol/farmacología , Ancylostoma/efectos de los fármacos , Animales , Antinematodos/metabolismo , Antinematodos/farmacología , Ascaris suum/efectos de los fármacos , Caenorhabditis elegans/efectos de los fármacos , Cricetinae , Ivermectina/farmacología , Ketamina/metabolismo , Ketamina/farmacología , Ratones , Nematodos/efectos de los fármacos , Nematodos/microbiología , Control Biológico de Vectores/métodosRESUMEN
Semi-intensive equine breeding system favors gastrointestinal nematode infections. The treatment of these infections is based on the use of anthelmintics. However, the inappropriate use of these drugs has led to parasitic resistance to the available active principles. The objective of this study was to evaluate the efficacy of the main classes of antiparasitic (ATP) used in control in adult and young animals, including: benzimidazoles (fenbendazole), pyrimidines (pyrantel pamoate), macrocyclic lactones (ivermectin and moxidectin), as well as the combination of active ingredients (ivermectin + pyrantel pamoate). The study was carried out in two military establishments, located in Rio Grande do Sul (RS), from January to December, 2018. The intervals between the treatments of the animals were performed from 30 to 90 days. Coproparasitological evaluations were determined by the egg count reduction in the faeces. Cyatostomine larvae were identified in pre and post-treatment cultures. The results demonstrated the multiple parasitic resistance of cyathostomins to fenbendazole, moxidectin in young animals, and to fenbendazole, pyrantel pamoate in adult animals. Thus, it is necessary to define or diagnose parasitic resistance to assist in the creation of prophylactic parasitic control, using suppressive treatment with ATP associated with integrated alternatives. The progress of parasitic resistance can be slowed.
Asunto(s)
Antinematodos , Resistencia a Múltiples Medicamentos , Personal Militar , Infecciones Equinas por Strongyloidea , Estrongílidos , Animales , Antinematodos/farmacología , Antinematodos/uso terapéutico , Brasil , Heces/parasitología , Caballos , Larva/efectos de los fármacos , Recuento de Huevos de Parásitos/veterinaria , Infecciones Equinas por Strongyloidea/tratamiento farmacológico , Infecciones Equinas por Strongyloidea/parasitología , Estrongílidos/efectos de los fármacosRESUMEN
The main goal of this work was to evaluate the in vitro biological activity of two ferrocenyl chalcones (FcC-1 and FcC-2) against Haemonchus contortus (third-stage larvae (L3)) and Nacobbus aberrans (second-stage juveniles (J2)). Both compounds were synthesized and characterized by usual spectroscopic methods and their molecular structures were confirmed by single-crystal X-ray diffractometry. Nematode strains were examined in terms of percentage mortality of H. contortus (L3) by the action of FcC-1, which showed an effectivity of 100% at a concentration of 342 µM in 24 h, with EC50 = 20.33 µM and EC90 = 162.76 µM, whereas FcC-2 had an effectivity of 72% at a concentration of 342 µM in 24 h, with EC50 = 167.39 µM and EC90 = 316.21 µM. The effect of FcC-1 against nematode phytoparasite N. aberrans showed a better percentage of 95% at a concentration of 342 µM, with EC50 = 7.18 µM and EC90 = 79.25 µM, whereas the effect of FcC-2 was 87% at 342 µM, with EC50 = 168 µM and EC90 = 319.56 µM at 36 h. After treatment, the scanning electron micrographs revealed deformities in the dorsal flank and posterior part close to the tail of H. contortus L3. They showed moderate in vitro nematicidal activity against H. contortus L3 and N. aberrans J2.