In vitro effects of Cucurbita moschata seed extracts on Haemonchus contortus

Evaluation of anthelmintic efficacy of ethanolic leaf extract of Juglans regia L. on Ascaridia galli: a comprehensive in vitro and in vivo study

Anthelmintic resistance in livestock animals has been spreading across the world in prevalence and severity. As a result, researchers are exploring alternative strategies to combat this issue, and one promising avenue is the utilization of medicinal plants. This study aims to investigate the anthelmintic efficacy of the crude ethanolic extract (CEE) derived from the leaves of Juglans regia against one of the most detrimental nematode parasites affecting poultry, namely Ascaridia galli (A. galli). For the in vitro studies, adult A. galli worms were collected from the naturally infected chickens and the efficacy of CEE was measured at the concentration of 25, 50, and 100 mg/ml using adult worm motility inhibition (WMI) assay. In addition, levamisole (0.55 mg/ml) was used as the positive control. Likewise, Phosphate buffered saline (PBS) was used as the negative control. For the in vivo studies, CEE of J.regia at the doses of 500, 1000, and 2000 mg/kg were evaluated in chickens experimentally infected with A. galli. The anthelmintic efficacy was monitored using faecal egg count reduction (FECR) and worm count reduction (WCR) assays. In vitro studies revealed significant (P < 0.001) anthelmintic effects of CEE of J.regia on the motility of A. galli worms at different hours post-exposure. At the concentration of 100 mg/ml, CEE resulted in 96.5% inhibition of worm motility at 24 h post-exposure. While the synthetic anthelmintic drug, levamisole caused the highest inhibition of worm motility (100%) at the same time period. The in vivo anthelmintic activity of CEE of J. regia demonstrated a maximum effect on day 14 post-treatment by inducing 67.28% FECR and 65.03% WCR. We observed no significant difference (P > 0.05) in worm counts between the negative control group and the chickens treated with CEE at the dosage of 500 mg/kg. Together, the results of the present study suggest that CEE of J. regia leaves possess anthelmintic properties and could be a potential source of novel anthelmintic compounds for controlling helminth parasites.

Anthelmintic potential of sulphonamides and Cucurbita pepo seeds extract on Heterophyes heterophyes experimentally infected mice

Since 1980s, no new drugs were described for treatment of heterophyiasis with many side effects of the currently used drug; praziquantel. This work aimed to study the therapeutic effect of clorsulon (sulphoamide) and aqueous extract of Cucurbita pepo in the treatment of experimental heterophyiasis. Mice were infected with encysted metacercaiae of Heterophyes heterophyes obtained from infected fish flesh. Mice were divided into five groups according to the drug used. The treatment started two weeks post-infection. Our results showed reduction of the recovered worm count with high efficacy of clorsulon and a moderate effect of C. pepo which was increased in the second week with much improvement of the intestinal histopathological changes. Scanning electron microscopy of adult H. heterophyes obtained from the intestine of mice treated with praziquantel appeared contracted with multiple small vesicles over the dorsal surface. Clorsulon produced loss of the spines on the lateral sides of the parasite with few vesicles whereas C. pepo seeds showed complete loss of the spines. In conclusion, clorsulon has high efficacy against H. heterophyes infection. Although the extract of C. pepo showed moderate curative effect against this parasite, it can be used in combination with other agents for a better synergistic effect.

Isotonic, aqueous-based media as simple and suitable test media for short-term Haemonchus placei adult worm motility assay

The solvating power of test media used in anthelmintic assays is critical to the validity of assay results, especially when evaluating plant extracts. High solutes in media lowers its solvating power, altering the range of concentrations available for investigation and assay performance. To identify simplified, well-tolerated media for adult Haemonchus placei with improved solvating power, we investigated the impact of varying solutions of pH (2.5-8.5), salinity (19-154 mM), and normal saline (NS) incorporating dissolution enhancers (acetone, propylene glycol, DMSO and Tween-80; 10-40% v/v) on the nematode over 3 h at room temperature. The performance of identified media, NS and 20% Tween-80 in NS, were evaluated by preparing sample extracts (acetone extract Sarcocephalus latifolius, AESL_20&10; and chloroform extract Vernonia amygdalina, CEVA_20&10) stock solutions (20 and 10 mg/mL) in them, assessed their apparent dissolution, and each highest stock solution that dissolves the extracts evaluated for anthelmintic activity against H. placei. We found isotonicity to be the critical-to-worm survival factor as H. placei survived 100% in pH solutions 3.5-8.5, and saline solutions 39-154 mM. The dissolution enhancers, at 40%, gave no survival. At 30% and 20%, only Tween-80 gave 92.5% and 100% survival, respectively. At 10%, Tween-80, acetone, DMSO and propylene glycol gave 100%, 100%, 87.5% and 0% survival, respectively. In 20% Tween-80 in NS, AESL_20&10 and CEVA_20&10 dissolved, furnishing wider concentration range (20-0 mg/mL); whereas only AESL₁₀ dissolved in NS (narrower concentration range, 10-0 mg/mL). The LC₅₀s (mg/mL) of 7.67 (AESL₁₀, NS) and 7.48 (AESL₂₀, Tween-80 in NS) were not significantly different (p > 0.05), while CEVA₂₀ (Tween-80 in NS) gave 2.67. Our findings show that NS and 20% Tween-80 in NS, as isotonic, aqueous-based media, are suitable, and well-tolerated as test media for adult H. placei in a short-term motility assay. Up to 30% Tween-80 could be used to enhance dissolution where necessary.

Phytochemical profile and anthelmintic effects of Laurus nobilis essential oil against the ovine nematode Haemonchus contortus and the murine helminth model Heligmosomoides polygyrus

Small ruminant production in tropical and temperate countries faced substantial anthelmintic resistance due to the intensive use of commercial anthelmintic drugs. Therefore, alternative treatments including natural bioactive compounds with anthelmintic potential have been investigated looking for its successfully use in the parasite control. In the present study, we describe the chemical profile of Laurus nobilis essential oil (EO), the in vitro anthelmintic activity of L. nobilis EO against Haemonchus contortus and its in vivo anthelmintic effect against the murine helminth parasite model Heligmosomoides polygyrus. Chromatographic profile of L. nobilis (EO) extracted from the leaves of L. nobilis have shown the presence of monterpens 1,8-cineol (Eucalyptol) (29.47%), D-Limonène (18.51%) and Linalool (10.84%) in high fractions. The in vitro anthelmintic potential was expressed by an ovicidal effect against H. contortus egg hatching with inhibition value of 1.72 mg/mL and 87.5% of immobility of adult worms after 8 h of exposure to 4 mg/mL of L. nobilis EO. Regarding, the in vivo anthelmintic potential, L. nobilis (EO) at 2400 mg/kg bw completely eliminated the egg output of H. polygyrus after 7 days of oral treatment, together with a 79.2% of reduction in total worm counts. Based on the obtained results, L. nobilis EO showed promising in vitro and in vivo anthelmintic capacities against gastrointestinal parasites.

Assessment of anthelmintic potentials of Myrtus communis against Haemonchus contortus and Heligmosomoides polygyrus

Anthelmintic resistance in grazing livestock systems has been spreading worldwide in prevalence and severity. Therefore, alternative measures including the use of herbal anthelmintic is considered as one of the successful approaches for the control of anthelmintic resistance. In the present report, we describe the chemical constituents of Myrtus communis essential oil, its in vitro anthelmintic effect against the most pathogenic gastrointestinal parasite of sheep; Haemonchus contortus and its in vivo anthelmintic potential using an in vivo gastrointestinal parasite model of rodents; i.e. Heligmosomoides polygyrus. Chromatographic analyzes of the essential oil (EO) extracted from the leaves of M. communis have shown that this oil was composed mainly of a α-pinene (33.59%), eucalyptol (23.85%) and limonene (14.70%). Regarding the in vitro anthelmintic potential, the ovicidal effect was confirmed in an egg hatch inhibition assay at IC₅₀ = 0.7 mg/mL and with 95.83% of immobility of adult worm's after 8 h of exposure to 2 mg/mL of M. communis EO. The anthelmintic capacity of M. communis EO was also confirmed by in vivo assays conducted against the murine parasite H. polygyrus. In fact, at 1200 mg/kg bw of M. communis EO, a reduction of 99.70% in faecal egg counts was observed after 7 days of oral treatment, together with a 71.12% reduction in total worm counts. Based on the obtained results, M. communis EO showed relevant in vitro and in vivo anthelmintic effects against gastro-intestinal parasites.

In Vitro Anthelmintic Activity and Phytochemical Screening of Crude Extracts of Three Medicinal Plants against Haemonchus Contortus in Sheep at Haramaya Municipal Abattoir, Eastern Hararghe

The current study was carried out to evaluate the anthelmintic efficacy of crude methanolic extracts of leaves of Croton macrostachyus and Nicotiana tabacum and rhizome parts of Zingiber officinale on nematode parasite, Haemonchus contortus. For these objectives, adult worm mortality assay (AWMA) was conducted on adult H. contortus to investigate the in vitro adulticidal effect of crude extracts from March to October 2021 G.C. The percentage yield of crude 99.9% methanolic extracts was 53%, 78%, and 44% for C. macrostachyus, N. tabacum, and Z. officinale, respectively. Phytochemical analysis using standard techniques was also used to detect secondary metabolites contained in the plants. The study revealed the presence of secondary metabolites such as tannins, flavonoids, steroids, and terpenoids in all extracts, which are considered to be the chemical components that are responsible for the wide therapeutic activities of several medicinal plants. In in vitro study, four graded concentrations of the crude extracts (500 mg/ml, 250 mg/ml, 125 mg/ml, and 62.5 mg/ml) were tested at regular time intervals, and parasite viability for 8 hours was recorded in triplicate. Albendazole (1.25 mg/ml) and distilled water were used as the positive and negative controls, respectively. At 4 hr posttreatment, the 62.5 mg/ml, 125 mg/ml, and 250 mg/ml concentrations of C. macrostachyus, N. tabacum, and Z. officinale extracts have caused significantly higher mortality (P < 0.05) compared to the albendazole. Methanolic extracts of C. macrostachyus, N. tabacum, and Z. officinale produced mortality of adult H. contortus significantly (P < 0.05) to the level of 93%, 83%, and 50% at concentration of 125 mg/ml at 4 hr posttreatment and meanwhile at 6 hr produced 100%, 100%, and 90%, respectively, at the same concentration. On the other hand, albendazole (1.25 mg/ml) killed 60% and 80% of the parasites at 4 hr and 6 hr posttreatment, respectively. Concentrations of all the extracts had showed a comparable and strong nematocidal effect on H. contortus having no significant difference with that of the positive control (P > 0.05) at 8 hr posttreatment period. Hence, the current study revealed that the extracts from three plants have potential anthelmintic effect, and we recommend further study on fractionating each component separately and validating the materials using other parasite developmental stages are warranted.

Herbal Medicines against Hydatid Disease: A Systematic Review (2000-2021)

Echinococcosis is a serious public health issue that affects people and livestock all over the world. Many synthetic and natural products have been examined in vitro and in vivo on Echinococcus species but only a few are used clinically, however, they may cause some complications and side effects. To overcome these limitations, new horizons of herbal drugs to cure echinococcosis are opening with every passing day. To summarize the developments during the last 21 years, we conducted this review of the literature to identify medicinal herbs utilized throughout the world that have anti-Echinococcus activity. From 2000 to 2021, data were carefully obtained from four English databases: Science Direct, PubMed, Scopus, and OpenGrey. Botanical name, extraction technique, extract quantities, efficacy, duration of treatment, year of publication, and half-maximal inhibitory concentration (IC50) values were all well noted. Ninety-one published papers, with 78 in vitro and 15 in vivo, fulfilled our selection criteria. Fifty-eight different plant species were thoroughly tested against Echinococcus granulosus. Zataria multiflora, Nigella sativa, Berberis vulgaris, Zingiber officinale (ginger), and Allium sativum were the most often utilized anti-Echinococcus herbs and the leaves of the herbs were extensively used. The pooled value of IC50 was 61 (95% CI 60−61.9) according to the random effect model and a large degree of diversity among studies was observed. The current systematic study described the medicinal plants with anti-Echinococcus activity, which could be investigated in future experimental and clinical studies to identify their in vivo efficacy, lethal effects, and mechanisms of action.

Cucurbitaceae COld Peeling Extracts (CCOPEs) Protect Plants From Root-Knot Nematode Infections Through Induced Resistance and Nematicidal Effects

With nematicides progressively being banned due to their environmental impact, an urgent need for novel and sustainable control strategies has arisen. Stimulation of plant immunity, a phenomenon referred to as "induced resistance" (IR), is a promising option. In this study, Cucurbitaceae COld Peeling Extracts (CCOPEs) were shown to protect rice (Oryza sativa) and tomato (Solanum lycopersicum) against the root-knot nematodes Meloidogyne graminicola and Meloidogyne incognita, respectively. Focusing on CCOPE derived from peels of melon (Cucumis melo var. cantalupensis; mCOPE), we unveiled that this extract combines an IR-triggering capacity with direct nematicidal effects. Under lab conditions, the observed resistance was comparable to the protection obtained by commercially available IR stimuli or nematicides. Via mRNA sequencing and confirmatory biochemical assays, it was proven that mCOPE-IR in rice is associated with systemic effects on ethylene accumulation, reactive oxygen species (ROS) metabolism and cell wall-related modifications. While no negative trade-offs were detected with respect to plant growth or plant susceptibility to necrotrophic pests or pathogens, additional infection experiments indicated that mCOPE may have a predominant activity toward biotrophs. In summary, the presented data illustrate a propitious potential for these extracts, which can be derived from agro-industrial waste streams.

Seeds of Cucurbita maxima and Carica papaya are effective for controlling monogeneans in the gills of Leporinus macrocephalus

This study was carried out to evaluate the anthelminthic efficacy of seeds of Cucurbita maxima and Carica papaya for controlling monogeneans in the gills of Leporinus macrocephalus, besides hepatosomatic and splenosomatic index and condition factor of host. The fish were fed with seeds of C. maxima or C. papaya for seven days, and these treatments did not cause any mortality among them. Jainus leporini, Urocleidoides paradoxus, Urocleidoides eremitus and Tereancistrum parvus were the monogeneans found, and their prevalence in fish fed with seeds of C. papaya was 100%, while in fish fed with C. maxima the prevalence was 42.8%. Fish fed with seeds of C. papaya showed decreased in intensity and abundance of monogeneans, while fish fed with seeds of C. maxima presented decreased in abundance. Feeding of L. macrocephalus with seeds of C. maxima or C. papaya had efficacy of 69.6 and 67.8%, respectively. The hepatosomatic index of fish fed with seeds of C. maxima or C. papaya was not affected by the treatments. However, the splenosomatic index and condition factor of fish fed with C. maxima seeds decreased. Seeds of C. maxima and C. papaya may be used for controlling monogeneans of L. macrocephalus in fish farming.

A Systematic Review on Comparative Analysis, Toxicology, and Pharmacology of Medicinal Plants Against Haemonchus contortus

Background:Haemonchus contortus is an important pathogenic nematode parasite and major economic constraint of small ruminants in tropics and subtropics regions. This review is an attempt to systematically address the; (a) efficacy of different plants against H. contortus by in vitro and in vivo proof; (b) toxicology, mechanism of action, and active phyto-compounds involve in anti-haemonchiasis activity; (c) and comparative analysis of plant species evaluated both in vitro and in vivo.

Methods: Online databases (Google Scholar, PubMed, Scopus, and ScienceDirect) were searched and published research articles (1980–2020) were gathered and reviewed.

Results: A total of 187 plant species were reported belonging to 59 families and 145 genera with Asteraceae and Fabaceae being frequently used. Out of the total plant species, 171 species were found to be evaluated in vitro and only 40 species in vivo. Twenty-four species were commonly evaluated for in vitro and in vivo anti-haemonchiasis activity. Among the reported assays, egg hatching test (EHT) and fecal egg count reduction (FECR) were the most widely used assays in vitro and in vivo, respectively. Moreover, sheep were the frequently used experimental model in vivo. After comparative analysis, Lachesiodendron viridiflorum, Corymbia citriodora, Calotropis procera, and Artemisia herba-alba were found highly effective both in vitro and in vivo. L. viridiflorum inhibited enzymatic activities and metabolic processes of the parasite and was found to be safe without toxic effects. C. citriodora was moderately toxic in vivo, however, the plant extract produced promising nematicidal effects by causing muscular disorganization and changes in the mitochondrial profile. Additionally, C. procera and A. herba-alba despite of their high anti-haemonchiasis activity were found to be highly toxic at the tested concentrations. C. procera caused perforation and tegumental disorganization along with adult worm paralysis. Nineteen compounds were reported, among which anethole and carvone completely inhibited egg hatching in vitro and significantly reduced fecal egg count, decreased male length, and reproductive capacity of female in vivo.

Conclusion: This review summarized different medicinal plants owing to nematicidal activities against H. contortus eggs, larvae, and adult worms. Plants like L. viridiflorum, C. citriodora, C. procera, and A. herba-alba, while compounds anethole and carvone having promising nematicidal activities and could be an alternative source for developing novel drugs after further investigation.

Essential oil of Mentha pulegium induces anthelmintic effects and reduces parasite-associated oxidative stress in rodent model

Following the previous findings reported by the present authors on the anthelmintic effect of hydro-ethanolic extract of Mentha pulegium, the volatile constituents of M. pulegium are now assessed in the present study by exploring its anthelmintic and its antioxidant proprieties using in vitro and in vivo assays. Egg hatch assay (EHA) and adult worm's motility assays (AWMA) were used to assess the in vitro activity against Haemonchus. contortus. The in vivo anthelmintic potential was evaluated in mice infected with Heligmosomoides polygyrus using faecal egg count reduction (FECR) and total worm count reduction (TWCR). M. pulegium EO demonstrated 100% inhibition in the EHA at 200 μg/mL (IC50 = 56.36 μg/mL). In the AWM assay, EO achieved total worms paralysis 6 h after treatment exposure. This nematicidal effect was associated to morphological damages observed in the cuticular's worm using environmental scanning electron microscopy (ESEM). At 400 mg/kg, M. pulegium oil showed 75.66% of FECR and 80.23% of TWCR. The antioxidant potential of this plant was also monitored by several in vitro assays: total antioxidant capacity was 205.22 mg GAE/g DW, DPPH quenching effect was IC50 = 140 μg/mL, ABTS activity IC50 = 155 μg/mL and FRAP effect of 660 μg/mL. Regarding the in vivo assay, M. pulegium EO demonstrated a protective effect against oxidative stress by increasing the activity of the endogenous antioxidants (SOD, CAT and GPx) during H. polygyrus infection.

Preliminary Report on the Effect of Savanna Plants Leucaena leucocephala, Parkia platycephala and Senna alata against Eggs and Immature Stages of Trichostrongylid Nematodes In Vitro

The current study evaluated the anthelmintic effect of different extracts of Leucaena leucocephala, Parkia platycephala, and Senna alata on trichostrongylid eggs and infective larvae and determined the potential active components of each plant. Dried and macerated plant material was concentrated using rotaevaporation to obtain the crude extract (CE), followed by solvent partitioning to obtain hexanic (HexE), acetatic (AcE), and butanolic (BuE) extracts used for phytochemical analysis and anthelmintic efficacy testing in vitro. All the crude and partitioned extracts tested showed inhibition activity in the hatching of trichostrongylid eggs. Larvicidal efficacy was observed at CE concentrations of 2.5, 5.0, and 7.5 mg/mL for P. platycephala and S. alata. However, L. leucocephala CE did not significantly reduce the number of living larvae in the tested concentrations. Chromatographic analysis revealed several active metabolites; gallic acid, ellagic acid, naringin, morin, and kaempferol on AcE of P. platycephala; gallic acid, rutin, and ellagic acid on BuE of P. platycephala; and gallic acid and naringin on BuE of L. leucocephala. The extracts of P. platycephala, L. leucocephala, and S. alata leaves showed egg hatching inhibition and larvicidal activity, probably produced by tannins and flavonoids, which may act alone or by synergism.

Phytochemical evaluation of Cucumis prophetarum: protective effects against carrageenan-induced prostatitis in rats

Phytochemical study of the MeOH extract of Cucumis prophetarum fruits (family Cucurbitaceae) by using different chromatographic techniques led to the isolation of three metabolites; spinasterol (1), cucurbitacin B (2), and 2-O-β-D-glucopyranosylcucurbitacin E (3). Their chemical structures were created on the basis of physical, chemical, spectroscopic data 1D (¹H and ¹³C NMR), and 2D NMR (HSQC and HMBC), as well as similarity with literature data. Cucurbitacin B (Cu-B) (2) was found to be the major constituent. Potential protective activities of MeOH extract, CHCl₃, and EtOAc fractions and Cu-B were evaluated against carrageenan-induced prostatic inflammation in rats. Acute toxicity was assessed by evaluating LD₅₀. Pretreatment with CHCl₃ fraction and Cu-B ameliorated the rise in the prostate index and obviously protected against histopathological changes. Further, MeOH, extract, CHCl₃, and EtOAc fractions as well as Cu-B significantly protected against oxidative stress in prostatic tissues. The anti-inflammatory activities of the extract, fractions and Cu-B were confirmed by ameliorating the rise in prostatic content of the inflammatory mediators TNF-α, IL-1β, COX-2, and iNOS induced by carrageenan. In addition, the rise in the chemotactic factors were myeloperoxidase (MPO), F4-80, and monocyte chemoattractant protein-1 (MCP-1) was significantly hampered. In conclusion, three known compounds (1-3) were isolated from Cucumis prophetarum fruits. Cu-B (2) was the major identified compound. Particularly, CHCl₃ fraction and isolated Cu-B exhibited potent anti-inflammatory activity against carrageenan-induced prostatitis. The anti-inflammatory activity can be attributed, at least partly, to inhibition of neutrophil and macrophage infiltration into prostatic tissues.

A systematic review of medicinal plants used against Echinococcus granulosus

Cystic echinococcosis (CE) is a zoonotic helminthiasis caused by different species of the genus Echinococcus, and is a major economic and public health concern worldwide. Synthetic anthelmintics are most commonly used to control CE, however, prolonged use of these drugs may result in many adverse effects. This study aims to discuss the in vitro/in vivo scolicidal efficacy of different medicinal plants and their components used against Echinococcus granulosus. Google Scholar, ScienceDirect, PubMed and Scopus were used to retrieve the published literature from 2000-2020. A total of 62 published articles met the eligibility criteria and were reviewed. A total of 52 plant species belonging to 22 families have been reported to be evaluated as scolicidal agents against E. granulosus worldwide. Most extensively used medicinal plants against E. granulosus belong to the family Lamiaceae (25.0%) followed by Apiaceae (11.3%). Among various plant parts, leaves (36.0%) were most commonly used. Essential oils of Zataria multiflora and Ferula asafetida at a concentration of 0.02, and 0.06 mg/ml showed 100% in vitro scolicidal activity after 10 min post application, respectively. Z. multiflora also depicted high in vivo efficacy by decreasing weight and size while also causing extensive damage to the germinal layer of the cysts. Plant-based compounds like berberine, thymol, and thymoquinone have shown high efficacy against E. granulosus. These plant species and compounds could be potentially used for the development of an effective drug against E. granulosus, if further investigated for in vivo efficacy, toxicity, and mechanism of drug action in future research.

Effect of Ginsenoside-Rh2 and Curcurbitacin-B on Cryptosporidium parvum in vitro

Ginsenoside-Rh2 and cucurbitacin-B (CuB) are secondary metabolites of Ginseng (Panax ginseng) and Cucurbitaceae plants respectively. We assessed the anticryptosporidial activity of these two functional compounds in a cell culture model of cryptosporidiosis. The highest concentration of each compound that was not toxic to the host cells was used to assess the activity against C. parvum during infection/invasion and growth in HCT-8 cell monolayers. Monolayers were infected with pre-excysted C. parvum oocysts. Infected monolayers were incubated at 37 °C for 24 h and 48 h in the presence of different concentrations of each test compound. A growth resumption assay was performed by incubating infected monolayers in the presence of compounds for 24 h followed by a second 24-h incubation in the absence of compound. To screen for invasion inhibiting activity, freshly excysted C. parvum sporozoites were pre-treated with different concentrations of compounds prior to adding them to the cell monolayers. Paromomycin, a known inhibitor of C. parvum, and DMSO were used as positive and negative control, respectively. The level of infection was initially assessed using an immunofluorescent assay and quantified by real-time PCR. Both compounds were found to strongly inhibit C. parvum intracellular development in a dose-dependent manner. IC₅₀ values of 25 μM for a 24 h development period and 5.52 μM after 48 h development were measured for Rh2, whereas for CuB an IC₅₀ value of 0.169 μg/ml and 0.118 μg/ml were obtained for the same incubation periods. CuB also effectively inhibited resumption of growth, an activity that was not observed with Rh2. CuB was more effective at inhibiting excystation and/or host cell invasion, indicating that this compound also targets extracellular stages of the parasite.

In Vitro Acaricidal Activity of Selected Medicinal Plants Traditionally Used against Ticks in Eastern Ethiopia

A study was carried out to evaluate the acaricidal activities of crude methanolic extract of leaves of six medicinal plants, namely, Vernonia amygdalina, Calpurnia aurea, Schinus molle, Ricinus communis, Croton macrostachyus, and Nicotiana tabacum, against Rhipicephalus (Boophilus) decoloratus and Rhipicephalus pulchellus using an in vitro adult immersion test. Five graded concentrations of the crude extracts, 6.25, 12.5, 25, 50, and 100 mg/ml, were tested at different time intervals, and temporal changes in tick viability were recorded for 24 hours. Diazinon (0.1%) and distilled water were used as positive and negative controls, respectively. Standard procedures were applied to screen the phytochemical constituents of the tested plant parts. Phytochemical screening showed the presence of a condensed amount of tannins in all extracts. Starting from 30 min post exposure, the 100 mg/ml concentration of C. aurea and R. communis extracts has caused significantly higher mortality (P < 0.05) compared to the diazinon. A significant increase in tick mortality started 2 hr post exposure with diazinon and 50 and 100 mg/ml concentrations of S. molle. Vernonia amygdalina extract and diazinon showed a significant increase in tick mortality 3 hr post exposure with 100 mg/ml concentration. Similarly, a significant increase in tick mortality started 2 hr post exposure with diazinon and 100 mg/ml concentrations of C. macrostachyus and N. tabacum. At 24 hr post exposure, diazinon and 50 and 100 mg/ml concentrations of all the extracts have caused significantly higher tick mortality than the rest of the concentrations (P < 0.05). Higher concentrations of all the extracts had showed a comparable and strong acaricidal effect on Rhipicephalus (Boophilus) decoloratus and Rhipicephalus pulchellus having no significant difference with that of the positive control (P > 0.05) at 24 hr post exposure period. Tick killing activity of all evaluated plant extracts increases with increasing exposure time and concentration as well. Thus, all the tested plants could be used against Rhipicephalus (Boophilus) decoloratus and Rhipicephalus pulchellus as a potential alternative to substitute commercially available drugs. We recommend further study on fractionating each component separately and validating the materials.

Cucurbits Plants: A Key Emphasis to Its Pharmacological Potential

Cucurbita genus has received a renowned interest in the last years. This plant species, native to the Americas, has served worldwide folk medicine for treating gastrointestinal diseases and intestinal parasites, among other clinical conditions. These pharmacological effects have been increasingly correlated with their nutritional and phytochemical composition. Among those chemical constituents, carotenoids, tocopherols, phenols, terpenoids, saponins, sterols, fatty acids, and functional carbohydrates and polysaccharides are those occurring in higher abundance. However, more recently, a huge interest in a class of triterpenoids, cucurbitacins, has been stated, given its renowned biological attributes. In this sense, the present review aims to provide a detailed overview to the folk medicinal uses of Cucurbita plants, and even an in-depth insight on the latest advances with regards to its antimicrobial, antioxidant and anticancer effects. A special emphasis was also given to its clinical effectiveness in humans, specifically in blood glucose levels control in diabetic patients and pharmacotherapeutic effects in low urinary tract diseases.

In vitro screening of 51 birdsfoot trefoil (Lotus corniculatus L.; Fabaceae) strains for anti-parasitic effects against Haemonchus contortus

Secondary plant compounds have shown bioactivity against multi-drug resistant Haemonchus contortus in small ruminants. This study screened 51 strains of birdsfoot trefoil (BFT, Lotus corniculatus) crude aqueous extracts (BFT-AqE) for anti-parasitic activity in vitro against egg hatching, and of those 51 strains, 13 were selected for further testing of motility of first (L1) and third stage (L3) larvae, and exsheathment of L3. Proanthocyanidin content ranged between 1.4 and 63.8 mg PAC g-1 powder across the 51 BFT strains. When tested against egg hatching, 21 of the 51 aqueous extracts had an EC50 of 1-2 mg powder mL-1, 70% of the strains were &gt;90% efficacious at 6 mg powder mL-1 and 11 of the strains were 100% efficacious at 3 mg powder mL-1 BFT-AqE. Across the 13 strains tested against L3, efficacy ranged from 0 to 75% exsheathment inhibition, and 17 to 92% L3 motility inhibition at a concentration of 25 mg powder mL-1 BFT-AqE. There was no correlation between the PAC content of BFT powders and the anti-parasitic activity of aqueous extracts, therefore other secondary compounds may have contributed to the observed anti-parasitic effects. Further testing of BFT using bioactivity-driven fractionation and screening of BFT populations for the identified anti-parasitic compounds is needed.

Efficacy, toxicity, and lethality of plants with potential anthelmintic activity in small ruminants in Brazil

SUMMARY The use of medicinal plants as a therapeutic method in the control of diseases has been increasing in animal production. In the case of small ruminants, the endoparasitic disease is a major concern, since they are considered the greater sanitary problem, especially when considering the phenomenon of parasite resistance to the medicines used. Therefore, the development of alternative methods of endoparasitary control in goats and sheep has become a pressing need. The use of plants to control endoparasites can reduce the use of chemical inputs, making more environmentally sustainable livestock, minimizing the occurrence of parasitic resistance to conventional medicines and contributing to the reduction of production costs. In this sense, several studies have been carried out in order to evaluate the in vitro and in vivo activity of plants with anthelmintic potential. However, despite the potentiality found in many studies, the results are sometimes contradictory or do not replicate in vivo the same efficacy obtained in the in vitro assays. Another relevant aspect is the low utilization of the lethality and toxicity tests, which are indispensable so that the knowledge can be spread and applied by the producers in their herds. Thus, this review aims to provide the results from studies carried out in Brazil with extract of plants with potential for control of parasitic disease in goats and sheep, describing the main evaluated plants species, mechanisms of action, preparation forms and tests of efficacy, toxicity, and lethality.

In vitro effects of aqueous extract from Maytenus senegalensis (Lam.) Exell stem bark on egg hatching, larval migration and adult worms of Haemonchus contortus

Background

Maytenus senegalensis is a common shrub which is scattered in tropical Africa. Different parts of this plant have been reported to be useful in traditional medicine against gastrointestinal disorders and intestinal worms. This study evaluated the anthelmintic activity of the aqueous stem bark extract of M. senegalensis using egg hatch assay (EHA), larval migration inhibition assay (LMIA) and adult worms’ motility inhibition assay (AMIA).

Results

On EHA, the extract concentrations tested resulted in a significant (p < 0.01) inhibition of egg hatching in concentration-dependent manner and ranged between 31.86% at 75 μg.mL^− 1 to 54.92% at 2400 μg.mL^− 1 after a 48 h post-exposure with eggs. For the LMI assays, the aqueous extract of M. senegalensis showed a significant (p < 0.05) inhibition of larval migration in a concentration-dependent manner. The highest concentration used (2400 μg.mL^− 1) showed a 37.77% inhibition. The use of polyvinyl polypyrrolidone (PVPP) indicated that tannins and flavonoids were partly involved in the effect since the larval migration was inhibited by 15.5%, but other biochemical compounds were also implicated. On AMIA, M. senegalensis was associated with a reduced worm motility after a 24 h post exposure compared to phosphate buffered saline as control (p < 0.05). By this time 66.66% of the worms’ were found immotile or dead in the wells containing plant extract at 2400 μg.mL^− 1. The Phytochemical analysis of aqueous extract of M. senegalensis by HPLC-ESI-MSⁿ detected the presence of proanthocyanidins (20%) and flavonoids (> 50%).

Conclusions

These in vitro results suggest the presence of some anthelmintic properties in M. senegalensis extract, which is traditionally used by small farmers in west and central Africa. These effects may be due to the flavonoids and proanthocyanidins present in the extract and need to be studied under in vivo conditions.

Anthelmintic efficacy of cranberry vine extracts on ovine Haemonchus contortus

The discovery that plant secondary compounds, including proanthocyanidins (PAC), suppress gastrointestinal nematode (GIN) infection has provided promise for alternative methods of GIN control in small ruminants. This investigation is the first to examine the anthelmintic potential of cranberry vine (CV) against the GIN Haemonchus contortus. The purpose of this study was to explore the anti-parasitic activity of CV in the form of a specific organic proanthocyanidin extract (CV-PAC) and an aqueous extract (CV-AqE) containing PAC and other compounds. In vitro egg hatching, first (L1) and third (L3) stage larval and adult worm motility and L3 exsheathment were evaluated after a 24-h incubation with CV products. In addition, CV treated worms were observed via scanning electron microscopy, and a preliminary investigation of the efficacy of CV powder against an experimental infection of H. contortus was conducted. The in vivo effect on an experimental infection was determined by administering 21.1 g CV powder to lambs (n = 9 per group) for three consecutive days, and collecting fecal egg count data for four weeks post-treatment. The effect of CV-PAC on egg hatching, L3 motility and exsheathment was limited. However, a substantial effect was observed on motility of post-hatch L1 (EC₅₀ 0.3 mg PAC/mL) and adults (EC₅₀ 0.2 mg PAC/mL). The CV-AqE showed more effect on egg hatching (EC₅₀ 5.3 mg/mL containing 0.6 mg PAC/mL) as well as impacting motility of L1 (EC₅₀ 1.5 mg/mL with 0.2 mg PAC/mL) and adults (EC₅₀ 3.4 mg/mL with 0.4 mg PAC/mL), but like CV-PAC, did not substantially effect L3 motility or exsheathment. Scanning electron microscopy revealed an accumulation of aggregate on the cuticle around the buccal area of adult worms incubated in CV-AqE and CV-PAC. In the preliminary in vivo study, there was a significant effect of treatment over time (p = .04), although differences in individual weeks were not significant. In summary, both extracts inhibited motility of L1 and adult worms. The higher efficacy of CV-AqE than CV-PAC at levels that contained the same concentrations of PAC tested alone, suggest that other secondary compounds in the CV-AqE contributed to the observed effects on the parasites. This first study of the in vitro and in vivo effects of CV suggest that this readily available plant product may have utility in integrated control of H. contortus and support the need for additional testing to provide further information.

Comparison of the in vitro anthelmintic effects of Acacia nilotica and Acacia raddiana

Gastrointestinal nematodes are a major threat to small ruminant rearing in the Sahel area, where farmers traditionally use bioactive plants to control these worms, including Acacia nilotica and Acacia raddiana. The main aim of this study was to screen the potential anthelmintic properties of aqueous and acetone extracts of leaves of these two plants based on three in vitro assays: (1) the egg hatch inhibition assay (EHA); (2) the larvae exsheathment inhibition assay (LEIA) using Haemonchus contortus as a model; and (3) an adult mortality test (AMT) applied on Caenorhabditis elegans. For the EHA, only A. raddiana was effective with IC₅₀ = 1.58 mg/mL for aqueous extract, and IC₅₀ = 0.58 mg/mL for acetonic extract. For the LEIA, all extracts inhibited the exsheathment of larvae compared to the controls, and the aqueous extract of A. nilotica was more larvicidal with IC₅₀ = 0.195 mg/mL. In general, all responses to the substances were dose-dependent and were significantly different from the control group (p < 0.05). For the AMT, the extracts of the two Acacia species were effective but A. raddiana showed greater efficacy with 100% mortality at 2.5 mg/mL and LC₅₀ = 0.84 mg/mL (acetonic extract). The addition of polyvinyl polypyrrolidone (PVPP) to the extracts suggested that tannins were responsible for blocking egg eclosion and inducing adult mortality but were not responsible for exsheathment inhibition. These results suggest that the leaves of these Acacia species possess ovicidal and larvicidal activities in vitro against H. contortus, and adulticidal effects against C. elegans.

Anthelmintic activity of Moringa oleifera seed aqueous and ethanolic extracts against Haemonchus contortus eggs and third stage larvae

Haemonchus contortus is one of the prevalent and pathogenic ruminant parasites that has grown resistance to common anthelmintic treatment. This study evaluated the anthelmintic potential of Moringa oleifera seed ethanolic and aqueous extracts against H. contortus eggs and infective stage larvae (L3s). The efficacy of five extract concentrations (0.95, 1.95, 3.9, 7.8, and 15.6 mg/mL) were tested through egg hatch assay and larval motility test. Phytochemical tests were conducted to detect the different plant secondary metabolites in the extracts. In the ovicidal assay, the ethanolic and aqueous extracts showed 95.89% and 81.72% egg hatch inhibition at 15.6 mg/mL, respectively. The ovicidal activity of 15.6 mg/mL ethanolic extract was comparable with that of albendazole (p > 0.05). The LC₅₀ against the eggs was recorded at 2.91 and 3.83 mg/mL for ethanolic and aqueous extracts, respectively. In the larvicidal assay, the ethanolic and aqueous extracts exhibited 56.94% and 92.50% efficacy at 7.8 mg/mL, respectively. The larvicidal activity of 7.8 mg/mL aqueous extract was similar statistically with that of ivermectin (p > 0.05). The LC₅₀ against L3s was recorded at 6.96 and 4.12 mg/mL for ethanolic and aqueous extracts, respectively. The secondary metabolites detected were tannins in ethanolic extract and saponins in aqueous extract. Both extracts inhibited larvae formation inside the eggs and rendered the L3s immobile. Therefore, M. oleifera seed extracts contained plant bioactive compounds with anthelmintic property against the eggs and L3s of H. contortus.

Evaluation of Anthelmintic Activity and Composition of Pumpkin (Cucurbita pepo L.) Seed Extracts-In Vitro and in Vivo Studies

A significant number of studies report growing resistance in nematodes thriving in both humans and livestock. This study was conducted to evaluate the in vitro and in vivo anthelmintic efficiency of Curcubita pepo (C. pepo) L. hot water extract (HWE), cold water extract (CWE) or ethanol extract (ETE) on two model nematodes: Caenorhabditis elegans (C. elegans) and Heligmosoides bakeri (H. bakeri).

METHODS

Raman, IR and LC-MS spectroscopy analyses were performed on the studied plant material to deliver qualitative and quantitative data on the composition of the obtained extracts: ETE, HWE and CWE. The in vitro activity evaluation showed an impact of C. pepo extracts on C. elegans and different developmental stages of H. bakeri. The following in vivo experiments on mice infected with H. bakeri confirmed inhibitory properties of the most active pumpkin extract selected by the in vitro study. All of the extracts were found to contain cucurbitine, aminoacids, fatty acids, and-for the first time-berberine and palmatine were identified. All C. pepo seed extracts exhibited a nematidicidal potential in vitro, affecting the survival of L1 and L2 H. bakeri larvae. The ETE was the strongest and demonstrated a positive effect on H. bakeri eggs hatching and marked inhibitory properties against worm motility, compared to a PBS control. No significant effects of pumpkin seed extracts on C. elegans integrity or motility were found. The EtOH extract in the in vivo studies showed anthelmintic properties against both H. bakeri fecal egg counts and adult worm burdens. The highest egg counts reduction was observed for the 8 g/kg dose (IC50 against H. bakeri = 2.43; 95% Cl = 2.01-2.94). A decrease in faecal egg counts (FEC) was accompanied by a significant reduction in worm burden of the treated mice compared to the control group.

CONCLUSIONS

Pumpkin seed extracts may be used to control of Gastrointestinal (G.I.) nematode infections. This relatively inexpensive alternative to the currently available chemotherapeutic should be considered as a novel drug candidate in the nearest future.

Traditional plant-based remedies to control gastrointestinal disorders in livestock in the regions of Kamina and Kaniama (Katanga province, Democratic Republic of Congo)

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrointestinal parasitic diseases present one of the main constraints hindering the productivity of the livestock sector (goat and cattle). Due to the limited availability and affordability of deworming drugs, traditional herbal remedies are still frequently used. The study aims at collecting traditional knowledge on local plants and remedies used to treat gastrointestinal parasitoses in livestock in two adjacent territories (Haut-Lomami district).

MATERIAL AND METHODS

A field survey was carried out in a part of the Haut-Lomami district (province of Katanga). A semi-structured questionnaire was used to interview 44 people including farmers, traditional healers and livestock specialists (veterinarians and agronomist), identified as using or practicing traditional medicine. To prepare botanically identified herbarium specimens, cited plants were collected with the participation of interviewed people.

RESULTS

Although interviewed people cannot precisely identify the etiology of gastrointestinal disorders/parasitoses in domestic animals, they treat the condition with herbals collected in their near environment. Nineteen different traditional remedies were collected and described; 9 plant species were identified as commonly used to treat gastrointestinal parasitic infections. From these, Vitex thomasii De Wild (Verbenaceae) appears as the plant most often used.

CONCLUSION

This survey contributed to the establishment of an inventory of plants used in livestock parasitic treatment in this region of the Democratic Republic of Congo. Future studies are needed to confirm the efficacy and safety of these traditional remedies.

Participatory study of medicinal plants used in the control of gastrointestinal parasites in donkeys in Eastern Shewa and Arsi zones of Oromia region, Ethiopia

Background

Gastrointestinal nematode infections constitute a threat to the health and welfare of donkeys worldwide. Their primary means of control is via anthelmintic treatments; however, use of these drugs has constraints in developing countries, including cost, limited availability, access to cheaper generic forms of variable quality and potential anthelmintic resistance. As an alternative, bioactive plants have been proposed as an option to treat and control gastrointestinal helminths in donkeys. This study aimed to use participatory methodology to explore donkey owner knowledge, attitudes and beliefs relating to the use of plant-based treatments for gastrointestinal parasites of donkeys in Ethiopia.

Results

In focus groups, 22/29 groups stated they knew of plants used for the treatment of gastrointestinal parasites in donkeys. All groups volunteered plants that were used in cattle and/or small ruminants. In total, 21 plants were named by participants. ‘Koso’ (Hagenia abyssinica) ‘Grawa’ (Vernonia amygdalina) and a mixed roots and leaves preparation were the most frequently named plant preparations. ‘Enkoko’ (Embelia shimperi) and ‘a mixture of roots and leaves’ were ranked highly for effectiveness in donkeys. However, ‘Grawa’ and ‘Koso’ were the highest ranked when taking into account both the rank position and the number of groups ranking the plant.

Thematic analysis of participants’ current attitudes and beliefs surrounding traditional plant-based remedies for gastrointestinal parasites revealed that anthelmintics obtained from clinics were generally favoured due to their ease of administration and perceived higher effectiveness. There was doubt surrounding the effectiveness of some plant-based treatments, but there were also perceived advantages including their low cost, ease of cultivation and availability. However, plant-based treatments were considered a “past trend” and people favoured “modern” medicine, particularly among the younger generation.

Conclusions

There was extensive knowledge of plant-based treatments for gastrointestinal parasites in livestock in Ethiopia. In donkeys, Koso (Hagenia abyssinica), Grawa (Vernonia amygdalina), Enkoko (Embelia shimperi) and ‘mixed roots and leaves’ were the most frequently named and/or highest ranked plants with reported efficacy against gastrointestinal parasites. Further in vitro and in vivo investigation of these plants is now required to determine viable alternatives for the treatment and control of gastrointestinal parasites in Ethiopia.

Anthelmintic activity of Arisaema franchetianum and Arisaema lobatum essential oils against Haemonchus contortus

ETHNOPHARMACOLOGICAL RELEVANCE

Arisaema franchetianum and Arisaema lobatum are two perennial plants native to China. Arisaema franchetianum is universally used to promote the subsidence of induration and swelling, quicken blood and relieve pains, and kill intestinal parasites in humans and animals. Arisaema lobatum is used to treat malaria, intestinal parasites, and snake and insect bites in humans and animals. The aim of this study was to determine the composition of the essential oils from Arisaema franchetianum and Arisaema lobatum and evaluate the anthelmintic effect against Haemonchus contortus.

MATERIALS AND METHODS

Two oils were investigated by GC and GC-MS. The anthelmintic bioassay tests of Arisaema franchetianum and Arisaema lobatum essential oil, linalool and carvacrol were performed using egg hatch assay (EHA), larval development assay (LDA) and larval migration inhibition assay (LMIA).

RESULTS

Fifty six components representing 96.88% of the Arisaema franchetianum oil and 64 components representing 96.88% of the Arisaema lobatum oil were identified. Carvacrol and linalool were found to be the major constituents of two oils. In the EHA, greater than 99% inhibition were observed with Arisaema franchetianum oil at 10mg/mL (CE50 1.63mg/mL) and Arisaema lobatum oil at 5 and 10mg/mL (CE50 0.48mg/mL). In the LDA, both oils induced complete inhibition at 10mg/mL, with the CE50 being 1.10mg/mL for Arisaema franchetianum oil and 0.73mg/mL for Arisaema lobatum oil. In the LMIA, the Arisaema franchetianum oil and Arisaema lobatum oil at best inhibited 74.1% and 95.6% of larval migration at 10mg/mL, respectively. Carvacrol exhibited similar activity to Arisaema lobatum essential oil and linalool did not show high activity in every assay.

CONCLUSIONS

These data show for the first time that the essential oils obtained from Arisaema franchetianum or Arisaema lobatum had promising anthelmintic activity against Haemonchus contortus. Arisaema plant may offer an alternative source for the control of gastrointestinal nematodes of sheep and goats.

In vitro effect of heather (Ericaceae) extracts on different development stages of Teladorsagia circumcincta and Haemonchus contortus

The aim of the present study was to evaluate the in vitro effects of heather (Ericaceae) phenolic extracts on the abomasal nematodes Teladorsagia circumcincta and Haemonchus contortus. Extracts of three heather species (Calluna vulgaris, Erica cinerea, Erica umbellata and a balanced mixture of all three) were tested in vitro on different development stages of T. circumcincta (eggs, infective larvae and adult worms) and H. contortus (eggs and infective larvae) using an egg hatching assay (EHA), a larval exsheathment inhibition assay (LEIA) and an adult motility inhibition assay (AMIA). The egg hatching rate was measured after incubation with heather extracts for 48 h at 25 °C. Ensheathed infective larvae were incubated for 3h at 20 °C with heather extracts. Artificial exsheathment was induced in vitro by adding hypochloride solution to the larval suspension. The progress of exsheathment over time was measured by repeated observations at 10-min (T. circumcincta) and 20-min (H. contortus) intervals for 60 min. Adult T. circumcincta worms were obtained from two donor goats and incubated with the extracts at 37 °C for 3 days in 48-well multiwell plates. Worm motility was measured at 0, 19, 24, 43, 48, 67 and 72 h. The extracts were tested at concentrations of 75, 150, 300, 600 and 1200 μg/mL. Incubation with E. cinerea, E. umbellata and mixed heather extracts had a significant (P<0.01) dose-dependent effect on T. circumcincta egg hatching. H. contortus egg hatching was significantly (P<0.01) inhibited only by the E. cinerea extract. All extracts had a significant (P<0.01) dose-dependent effect on the exsheathment of T. circumcincta and H. contortus infective larvae. The incubation with all heather extracts induced a reduction in adult T. circumcincta motility compared to the control, although significant (P<0.05) differences were only found at the highest concentration (1200 μg/mL). The effect of the mixed extract was significant at all concentrations and significant effects were also observed for C. vulgaris and E. umbellata at 600 μg/mL. These results show anthelmintic properties of heather phenolic extracts against T. circumcincta and H. contort, thus confirming observations from previous in vivo studies.

In vitro ovicidal and larvicidal activity of the essential oil of Artemisia lancea against Haemonchus contortus (Strongylida)

Prolonged use of chemical anthelmintics has been found to result in anthelmintic resistance and environmental issues, thereby limiting the application of these drugs in domestic animals and prompting interest in the study of plant extracts as alternative sources thereof. The aim of this study was to evaluate the in vitro effect of the essential oil (EO) of Artemisia lancea against the parasitic nematode Haemonchus contortus using egg hatch assay, larval development assay, and larval migration inhibition assay. The EO yield of extraction was 0.63% (w/w), and the major constituents were 1,8-cineole (34.56%) and camphor (16.65%). In the egg hatch assay, an inhibition greater than 99% was observed with the EO at 10 mg mL(-1) and the LC50 was 1.82 mg mL(-1). 1,8-Cineole demonstrated moderate ovicidal activity with a LC50 of 4.64 mg mL(-1), whereas camphor did not show enough activity to have its LC50 determined. In the larval development assay, the EO, 1,8-cineole, and camphor inhibited 93.6%, 65.2%, and 57% of larval development at 10 mg mL(-1) and exhibited dose-dependent responses with LC50 values of 1.66, 5.07, and 7.80 mg mL(-1), respectively. In the migration inhibition assay, the EO and 1,8-cineole at best inhibited 77% and 60.3% of larval migration at 10 mg mL(-1), respectively. Camphor showed low inhibition capacity, and its efficacy was not dose dependent. The results indicate that the in vitro anthelmintic activity of the EO of A. lancea may be associated with the additive action of the two major constituents, as well as other more minor terpenoid components.

In vitro activities of acetonic extracts from leaves of three forage legumes (Calliandra calotyrsus, Gliricidia sepium and Leucaena diversifolia) on Haemonchus contortus

OBJECTIVE

To assess ovicidal activity of three acetonic extracts from the leaves of three forage legume, Calliandra calotyrsus (C. calotyrsus), Gliricidia sepium (G. sepium) and Leucaena diversifolia (L. diversifolia) in vitro on Haemonchus contortus (H. contortus).

METHODS

Eggs were exposed for 24 hours to five different concentrations (0.075, 0.15, 0.3, 0.6 and 1.25 mg/mL) of acetonic extracts at room temperature (24 °C). Distilled water and 0.4% Tween were used in the bioassay as negative controls.

RESULTS

The later did not affect embryonation and egg hatching of H. contortus. Conversively, significant effects were obtained with the acetonic extracts of leaves of all three plants and the maximum activity was observed with the highest concentration (1.25 mg/mL). The acetonic extract of G. sepium was found to be more active (2.9% and 0.0% for embryonation and egg hatching, respectively) than the other substances 16.5% and 33.5%, respectively for C. calothyrsus, 33.7% and 33.3%, respectively for L. diversifolia.

CONCLUSIONS

These results suggest that the three forage legumes do possess ovicidal properties and further studies on larvae should be carried out.

Research and implementation of novel approaches for the control of nematode parasites in Latin America and the Caribbean: is there sufficient incentive for a greater extension effort?

The widespread presence of anthelmintic resistant gastrointestinal parasitic nematodes in outdoor ruminant production systems has driven the need to identify and develop novel approaches for the control of helminths with the intention to reduce the dependence on commercial anthelmintic drugs. This paper identifies what has been done in Latin America (LA) in terms of estimating the prevalence of anthelmintic resistance (AR) in ruminant production systems and the application of different novel approaches for the control of helminths in those systems, including research and extension activities. Firstly, the paucity of knowledge of AR is discussed in the context of different countries, as well as, the available economic resources for research, the technical infrastructure available and the practical difficulties of the production systems. It is then proposed that the search for novel approaches is not only driven by AR but also by the need for techniques that are feasible for application by resource-poor farmers in non-commercial subsistence farming systems. However, the commercial benefits of these approaches are often limited and so are funding inputs in most countries. The workers participating in the research into different novel approaches are identified as well as the different methods being studied in the different areas of LA according to their published results. In addition, the difficulties experienced during extension efforts to reach farmers and help them to adopt novel approaches for the control of parasitic nematodes in LA are discussed. The role of regulatory authorities in these countries is discussed as some methods of control might need an official confirmation of their efficacy as well as authorization prior to application as they may affect animal products (i.e. residues) and/or impose a hazard for animal welfare. The role of the pharmaceutical companies is also discussed.

The In Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae)

A comparative in vitro study was carried out to determine the ovicidal and larvicidal activity of aqueous and ethanolic extracts of Ageratum conyzoides (Asteraceae) leaves on the eggs (unembryonated and embryonated), first and second larval stages of Heligmosomoides bakeri. Four different concentrations (0.625, 1.25, 2.5, and 3.75 mg·mL(-1)) of both aqueous and ethanolic extracts were tested. Distilled water and 5% tween were used as negative controls in the bioassay. In fact, they did not affect development of eggs, hatching, and larval survival. The extract activities were dose dependent. The ethanolic extract was more potent against embryonation (39.6 ± 2.9%) than the aqueous extract (53.3 ± 10.9%) at the highest concentration (3.75 mg·ml(-1)). Both types of extracts killed larvae. Mebendazole proved more lethal (EC(50) of 0.745 and 0.323 mg·mL(-1), resp., for L(1) and L(2) larvae). The aqueous extracts were the least lethal (EC(50) of 4.76 and 2.29 mg·mL(-1), resp., for L(1) and L(2) larvae). The ethanolic extracts showed intermediate activity (EC(50) of 1.323 and 1.511 mg·mL(-1), resp., for L(1) and L(2) larvae). It is concluded that the ovicidal and larvicidal properties of aqueous and ethanolic extracts of Ageratum conyzoides leaves are demonstrated in this work.

Caenorhabditis elegans as a model to screen plant extracts and compounds as natural anthelmintics for veterinary use

The most challenging obstacles to testing products for their anthelmintic activity are: (1) establishing a suitable nematode in vitro assay that can evaluate potential product use against a parasitic nematode of interest and (2) preparation of extracts that can be redissolved in solvents that are miscible in the test medium and are at concentrations well tolerated by the nematode system used for screening. The use of parasitic nematodes as a screening system is hindered by the difficulty of keeping them alive for long periods outside their host and by the need to keep infected animals as sources of eggs or adults when needed. This method uses the free-living soil nematode Caenorhabditis elegans as a system to screen products for their potential anthelmintic effect against small ruminant gastrointestinal nematodes, including Haemonchus contortus. This modified method uses only liquid axenic medium, instead of agar plates inoculated with Escherichia coli, and two selective sieves to obtain adult nematodes. During screening, the use of either balanced salt solution (M-9) or distilled water resulted in averages of 99.7 (± 0.73)% and 96.36 (± 2.37)% motile adults, respectively. Adult worms tolerated DMSO, ethanol, methanol, and Tween 80 at 1% and 2%, while Labrasol (a bioenhancer with low toxicity to mammals) and Tween 20 were toxic to C. elegans at 1% and were avoided as solvents. The high availability, ease of culture, and rapid proliferation of C. elegans make it a useful screening system to test plant extracts and other phytochemical compounds to investigate their potential anthelmintic activity against parasitic nematodes.

Efficacy of anthelmintic properties of medicinal plant extracts against Haemonchus contortus

The development of anthelmintic resistance has made the search for alternatives to control gastrointestinal nematodes of small ruminants imperative. Among these alternatives are several medicinal plants traditionally used as anthelmintics. This present work evaluated the efficacy of ethyl acetate, acetone, and methanol dried leaf and seed extracts of five medicinal plants were tested in vitro ovicidal and larvicidal activities on Haemonchus contortus. The in vitro assay was based on egg hatch assay (EHA) and larval development assay (LDA), all plant extracts were evaluated at five concentrations 50, 25, 12.5, 6.25 and 3.13 mg/ml. The leaf and seed ethyl acetate, acetone and methanol of Annona squamosa, Eclipta prostrata, Solanum torvum, Terminalia chebula, and Catharanthus roseus extracts were showed complete inhibition (100%) at the maximum concentration tested (50 mg/ml). The overall findings of the present study have shown that our experimental plant extracts contain possible anthelmintic compounds.

In vitro nematicidal activity of extracts of Canthium mannii (Rubiaceae), on different life-cycle stages of Heligmosomoides polygyrus (Nematoda, Heligmosomatidae)

The increasing prevalence of anthelmintic-resistant strains of helminths, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintic. The potential nematicidal activities of four extracts from the bark of Canthium mannii (Rubiaceae) stem were investigated in vitro. Extracts were diluted in distilled water (DW) to obtain five different concentrations (1.5, 2.0, 2.5, 3.0 and 3.5 mg/ml) and put in contact with eggs and larvae of Heligmosomoides polygyrus. The different stages of the life cycle were also put in contact with the same concentration of mebendazole (MBZ, positive control). One millilitre of each extract at different concentrations and control were added to 1 ml solution containing 30–40 eggs or 10–15 larvae (L1, L2 and L3) and distributed in different Petri dishes. The eggs and larvae were incubated at 24°C and exposure times were: 48 h for un-embryonated eggs, 6 h for embryonated eggs; 2, 4, 6 and 24 h for L1 and L2 larvae, 24–48 h for infective larvae (L3), and 5 days for the larval development test (from L1 to L3). DW and 1% dimethyl sulphoxide (DMSO) were used as placebo and DMSO control, respectively. Significant effects were obtained with three of the four extracts, and differences were observed depending on the parasite stage. Cold water extract (CWE), hot water extract (HWE) and ethanol extract (ETE) inhibited embryonic development (40, 45 and 10%) and hatching of embryonated eggs (40, 85 and 80%), respectively, at 3.5 mg/ml. Only ETE killed L1 (97.18%) and L2 (92.68%) larvae of H. polygyrus after 24 h at 3.5 mg/ml and drastically reduced the production rate (6% at 3.0 and 3.5 mg/ml) of infective larvae (L3) after 5 days of incubation compared to other extracts (P < 0.05). However, the infective larvae of H. polygyrus were resistant to the effect of each of the tested products (extracts and mebendazole). These in vitro results suggested that extracts of C. mannii, used by traditional healers in Dschang, Western Region of Cameroon (Central Africa) to cure intestinal helminthiasis and abdominal pains of their patients, possess nematicidal properties. The active principles responsible for the activity could be secondary metabolites such as alkaloids and saponins present in the extracts. It is suggested that further experiments incorporating in vivo purification of extracts and toxicological investigations should be carried out.