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

Two in vitro anthelmintic assays of four Paraguayan medicinal plants for proof of concept of the role of polyphenols in their biological activities and LC-HRMS analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrointestinal nematodes (GIN) control in small ruminants has relied on the systematic use of synthetic anthelmintics (AH), their effectiveness has been progressively decreasing due to the rise and diffusion of anthelmintic resistances. The most prevalent genera affecting small ruminants were Haemonchus spp., and Trichostrongylus spp. The investigation of new anthelmintics in plants is a highly studied option, especially when it is linked to ethnobotanical knowledge and phenolic compounds.

THE AIMS OF OUR STUDY

Four medicinal plants mentioned in traditional medicine were selected to evaluate their anthelmintic proprieties at different stages of the life cycle of GIN, namely: Kyllinga odorata Valh., Cassia occidentalis L., Artemisia absinthium L, and Verbena litoralis Kunth and to explore the role of polyphenols in the AH activity.

MATERIALS AND METHODS

To evaluate the anthelmintic activity in this study, two models of GIN species, namely Haemonchus contortus (Hc) and Trichostrongylus colubriformis (Tc) were selected and tested on two in vitro assays: 1) Larval Exsheathment Inhibition Assay (LEIA) and, 2) Egg Hatch Assay (EHA). To explore the role of tannins and polyphenols in AH activity by comparing the effects of LEIA and EHA with or without polyvinylpolypyrrolidone (PVPP) and to characterize the phytochemical composition of the most active plants using ultra-high performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS).

RESULTS

C. occidentalis exhibited the highest activity on LEIA (EC₅₀ = 250.42-41.80 μg/mL) and A. absinthium on egg hatching processes (EC₅₀ = 121.70-137.34 μg/mL) in both species of GIN. The inhibition in the development of eggs was from 67.70% to 96.36% on H. contortus, and from 78.87% to 99.65% on T. colubriformis. At the maximal dose, Additionally, it was observed that the AH on eggs varies according to the GIN species: on H. contortus the extracts tested blocked the formation of larvae Ovicidal Effect (% higher OE) and on T. colubriformis they blocked the appearance of L1 larvae, Larvae Failing Eclosion (% higher LFE). After PVPP, a reduction in AH activity on LEIA and EHA was noted, especially with C. occidentalis (87.20-67.00% of larvae exsheathment, (p < 0.05) and 40.51-24.96% of egg hatching, (p > 0.05) of both parasite species. Nine putative features were identified using HRMS and MS/MS after addition of PVPP.

CONCLUSIONS

The present study demonstrated that C. occidentalis, A. absinthium, and K. odorata, which parts have been traditionally used as medicinal plants are a valuable source of active compounds with anthelmintic activity. The medicinal use of these plants against GIN parasites was proven by in vitro analysis. Therefore exploration of the secondary metabolites of these plant extracts and testing of isolated fractions of active compounds under in vivo experiments are planned and represent a specific challenge for alternative drug research. Regarding the PVPP, in this study we hypotheses about the standard doses it was not able to completely absorb the polyphenols of extracts of K. odorata, C. occidentalis, and A. absinthium, which would lead to more studies to evaluate the role of this product in the absorption of phenolic compounds.

Combined analysis of metabolome and transcriptome of wheat kernels reveals constitutive defense mechanism against maize weevils

Sitophilus zeamais (maize weevil) is one of the most destructive pests that seriously affects the quantity and quality of wheat (Triticum aestivum L.). However, little is known about the constitutive defense mechanism of wheat kernels against maize weevils. In this study, we obtained a highly resistant variety RIL-116 and a highly susceptible variety after two years of screening. The morphological observations and germination rates of wheat kernels after feeding ad libitum showed that the degree of infection in RIL-116 was far less than that in RIL-72. The combined analysis of metabolome and transcriptome of RIL-116 and RIL-72 wheat kernels revealed differentially accumulated metabolites were mainly enriched in flavonoids biosynthesis-related pathway, followed by glyoxylate and dicarboxylate metabolism, and benzoxazinoid biosynthesis. Several flavonoids metabolites were significantly up-accumulated in resistant variety RIL-116. In addition, the expression of structural genes and transcription factors (TFs) related to flavonoids biosynthesis were up-regulated to varying degrees in RIL-116 than RIL-72. Taken together, these results indicated that the biosynthesis and accumulation of flavonoids contributes the most to wheat kernels defense against maize weevils. This study not only provides insights into the constitutive defense mechanism of wheat kernels against maize weevils, but may also play an important role in the breeding of resistant varieties.

In Vitro Evaluations and Comparison of the Efficacy of Two Commercial Products Containing Condensed Tannins and of Saifoin (Onobrychis viciifolia Scop.) Hay against Gastrointestinal Nematodes of Goats

Gastrointestinal nematodes (GINs) is a limiting health factor for dairy goats, and the integration of the diet with fodder containing condensed tannins (CT) is becoming increasingly important to control GINs. To preliminary evaluate their potential role as part of GIN control in goat breeding, the in vitro anthelmintic efficacy of the CTs of Silvafeed BYPRO (SBP), Silvafeed Q powder (SQ), and sainfoin hay (SH) was evaluated, and the untargeted metabolomics profiling of the selected formulations was performed. CTs were extracted in water and in ethanol, their concentration was determined, and their chemical characterization was conducted using High-Performance Liquid Chromatography (HPLC) coupled to High-Resolution Mass Spectrometry (HRMS) platform. The in vitro anthelmintic activity of the extracts was evaluated using the Eggs Hatch Test (EHT) and the Larval Migration Inhibition Test (LMIT) using different extract concentrations (150, 300, 600, and 1200 μg/mL). The metabolomic profile of the ethanol extract showed a high number of flavonoids, while the water extract showed higher levels of hydrolysable tannins. The ethanol extracts were effective on both eggs hatching and larvae migration at low concentrations (150 μg/mL) for the three analyzed samples, while the water extracts showed more varied results: SH showed the greatest ovicidal efficacy (concentration 150 μg/mL, %IH = 40.9), while SBP and SQ were more effective against the larvae migration (concentration 600 μg/mL, %LMI = 69.7% and 88%), respectively. The integration of CT-rich fodder into the diet may be considered for the control of GIN infection in goats.

An Inventory of Anthelmintic Plants across the Globe

A wide range of novelties and significant developments in the field of veterinary science to treat helminth parasites by using natural plant products have been assessed in recent years. To the best of our knowledge, to date, there has not been such a comprehensive review of 19 years of articles on the anthelmintic potential of plants against various types of helminths in different parts of the world. Therefore, the present study reviews the available information on a large number of medicinal plants and their pharmacological effects, which may facilitate the development of an effective management strategy against helminth parasites. An electronic search in four major databases (PubMed, Scopus, Web of Science, and Google Scholar) was performed for articles published between January 2003 and April 2022. Information about plant species, local name, family, distribution, plant tissue used, and target parasite species was tabulated. All relevant studies meeting the inclusion criteria were assessed, and 118 research articles were included. In total, 259 plant species were reviewed as a potential source of anthelmintic drugs. These plants can be used as a source of natural drugs to treat helminth infections in animals, and their use would potentially reduce economic losses and improve livestock production.

Safety and Tolerability of an Antimalarial Herbal Remedy in Healthy Volunteers: An Open-Label, Single-Arm, Dose-Escalation Study on Maytenus senegalensis in Tanzania

BACKGROUND

Though Maytenus senegalensis is one of the medicinal plants widely used in traditional medicine to treat infectious and inflammatory diseases in Africa, there is a lack of safety data regarding its use. Therefore, the study aimed to asselss the safety and tolerability of the antimalarial herbal remedy M. senegalensis.

MATERIAL AND METHODS

The study design was an open-label, single-arm, dose-escalation. Twelve eligible male healthy Tanzanians aged 18 to 45 years were enrolled in four study dose groups. Volunteers' safety and tolerability post-investigational-product administration were monitored on days 0 to 7,14, and 56.

RESULTS

There were no deaths or serious adverse events in any of the study groups, nor any adverse events that resulted in premature discontinuation. The significant mean changes observed in WBC (p = 0.003), Neutrophils (p = 0.02), Lymphocytes (p = 0.001), Eosinophils (p = 0.009), Alanine aminotransferase (p = 0.002), Creatinine (p = 0.03) and Total bilirubin (p = 0.004) laboratory parameters were not associated with any signs of toxicity or clinical symptoms.

CONCLUSIONS

M. senegalensis was demonstrated to be safe and tolerable when administered at a dose of 800 mg every eight hours a day for four days. This study design may be adapted to evaluate other herbal remedies.

Disclosing the bioactive metabolites involved in the in vitro anthelmintic effects of salt-tolerant plants through a combined approach using PVPP and HPLC-ESI-MSn

Strategies to reduce dependence on synthetic drugs for the treatment of gastrointestinal nematodes (GIN) infections in ruminants include the search for novel anthelmintic scaffolds on plants, yet salt-tolerant plants remain overlooked. This study aims to evaluate the in vitro anthelmintic properties of selected salt-tolerant plants against GIN, and identify the potential bioactive secondary metabolites involved. For that purpose, 80% acetone/water extracts were prepared from dried biomass of aerial organs of nine salt-tolerant plant species and tested against Haemonchus contortus and Trichostrongylus colubriformis by the Larval Exsheathment Inhibition Assay (LEIA) and Egg Hatching Inhibition Assay (EHIA). Pistacia lentiscus, Limoniatrum monopetalum, Cladium mariscus and Helychrisum italicum picardi were the most active in both GIN and life stages. To investigate the role of polyphenols in the anthelmintic activity, four selected extracts were treated with polyvinylpolypyrrolidone (PVPP), and non-treated and treated samples were further characterized by high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI-MSⁿ). While polyphenols seem responsible for the EHIA properties, they are partially accountable to LEIA results. Several phenolics involved in the anthelmintic effects were identified and discussed. In sum, these species are rich sources of anthelmintic compounds and, therefore, are of major interest for nutraceutical and/or phytotherapeutic applications against GIN in ruminants.

In Vitro Anthelmintic Evaluation of Gliricidia sepium, Leucaena leucocephala, and Pithecellobium dulce: Fingerprint Analysis of Extracts by UHPLC-Orbitrap Mass Spectrometry

In the present work, the anthelmintic activity (AA) of ethanolic extracts obtained from Gliricidia sepium, Leucaena leucocephala, and Pithecellobium dulce was evaluated using the third-stage-larval (L₃) exsheathment inhibition test (LEIT) and egg hatch test (EHT) on Haemonchus contortus. Extracts were tested at concentrations of 0.3, 0.6, 1.2, 2.5, 5.0, 10, 20, and 40 mg/mL. The larval exsheathment inhibition (LEI) results showed that G. sepium achieved the highest average inhibition of 91.2%, compared with 44.6% for P. dulce and 41.0% for L. leucocephala at a concentration of 40 mg/mL; the corresponding IC₅₀ values were 22.4, 41.7, and 43.3 mg/mL, respectively. The rates of egg hatching inhibition (EHI) at a concentration of 5 mg/mL were 99.5% for G. sepium, 64.2% for P. dulce, and 54% for L. leucocephala; the corresponding IC₅₀ values were 1.9 mg/mL for G. sepium, 3.9 mg/mL for P. dulce, and 4.3 mg/mL for L. leucocephala. The species extracts studied here were also analyzed by ultra-high performance liquid chromatography and Orbitrap high resolution mass spectrometry (UHPLC-Q/Orbitrap/MS/MS), resulting in the compounds' identification associated with AA. Glycosylated flavonoids and methoxyphenols were observed in all three species: fatty acids in G. sepium and P. dulce; phenylpropanoids, anthraquinone glycosides, amino acids and glycosylated phenolic acids in G. sepium; and flavonoids in L. leucocephala. Comparatively, G. sepium presented a greater diversity of compounds potentially active against the control of gastrointestinal nematodes, which was associated with the results obtained in the applied tests.

In vitro anthelmintic effects of Bridelia ferruginea, Combretum glutinosum, and Mitragyna inermis leaf extracts on Haemonchus contortus, an abomasal nematode of small ruminants

Gastrointestinal nematodes remain a major constraint on the health, welfare, and production of small ruminants. This study was conducted to evaluate three plant extracts (from Bridelia ferruginea, Combretum glutinosum, and Mitragyna inermis) as effective remedies against gastrointestinal parasites of small ruminants. Phytochemical screening was conducted on the plant leaves, and the potential anthelmintic properties of these plants were tested in vitro on Haemonchus contortus using the egg hatch, larval migration, and adult worm motility assays. The phytochemical screening of the leaves revealed the presence of several bioactive components in all the plants. The number of eggs that hatched was reduced in a concentration-dependent manner (p < 0.01) upon treatment with the methanol extract of B. ferruginea and the acetone extracts of C. glutinosum and M. inermis. The inhibitory effect of the acetone extract of B. ferruginea and the methanol extracts of C. glutinosum and M. inermis was not concentration-dependent (p > 0.05). There was a significant difference (p < 0.05) in the reduction in larval migration between the lowest concentrations (75 to 150 μg/mL) and the highest concentrations (300 to 1200 μg/mL) of plant extracts. The ability of plant extracts to affect the mobility of the adult worms was not concentration-dependent (p > 0.05); however, it was dependent on the time of incubation (p < 0.01). At the highest concentration (2400 μg/mL), all adult worms were motionless after 24 h of exposure, while at the lowest concentration (< 150 μg/mL), this occurred after 48 h of exposure. M. inermis and C. glutinosum extracts were more effective than B. ferruginea extracts (p < 0.05). Overall, these results suggest that these plants used by small-scale farmers possess antiparasitic properties useful for helminthiasis control. However, the effects of the plants remain to be confirmed via in vivo assays and toxicity tests in further studies.