Amoebicidal Activity of Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants in an Amoebic Liver Abscess Hamster Model

Identification and Characterization of Entamoeba histolytica Choline Kinase

PURPOSE

Entamoeba histolytica is one of the death-causing parasites in the world. Study on its lipid composition revealed that it is predominated by phosphatidylcholine and phosphatidylethanolamine. Further study revealed that its phosphorylated metabolites might be produced by the Kennedy pathway. Here, we would like to report on the characterizations of enzymes from this pathway that would provide information for the design of novel inhibitors against these enzymes in future.

METHODOLOGY

E. histolytica HM-1:IMSS genomic DNA was isolated and two putative choline/ethanolamine kinase genes (EhCK1 and EhCK2) were cloned and expressed from Escherichia coli BL21 strain. Enzymatic characterizations were further carried out on the purified enzymes.

RESULTS

EhCK1 and EhCK2 were identified from E. histolytica genome. The deduced amino acid sequences were more identical to its homologues in human (35-48%) than other organisms. The proteins were clustered as ethanolamine kinase in the constructed phylogeny tree. Sequence analysis showed that they possessed all the conserved motifs in choline kinase family: ATP-binding loop, Brenner's phosphotransferase motif, and choline kinase motif. Here, the open reading frames were cloned, expressed, and purified to apparent homogeneity. EhCK1 showed activity with choline but not ethanolamine. The biochemical characterization showed that it had a Vmax of 1.9 ± 0.1 µmol/min/mg. Its Km for choline and ATP was 203 ± 26 µM and 3.1 ± 0.4 mM, respectively. In contrast, EhCK2 enzymatic activity was only detected when Mn2+ was used as the co-factor instead of Mg2+ like other choline/ethanolamine kinases. Highly sensitive and specific antibody against EhCK1 was developed and used to confirm the endogenous EhCK1 expression using immunoblotting.

CONCLUSIONS

With the understanding of EhC/EK importance in phospholipid metabolism and their unique characteristic, EhC/EK could be a potential target for future anti-amoebiasis study.

Chemical Composition and Antiplasmodial Activity of the Essential Oil of Rhododendron subarcticum Leaves from Nunavik, Québec, Canada

Dwarf Labrador tea, Rhododendron subarcticum Harmaja, is a popular medicinal plant in use by First Nations of Northern Canada, but its phytochemistry has remained largely unexplored. We have isolated and characterized the essential oil from a population of this species harvested near the treeline in Nunavik, Québec. Analyses by gas chromatography-mass spectrometry (GC-MS) and gas chromatography/flame-ionization detection (GC/FID) led to the identification of 53 compounds; the main secondary metabolites were ascaridole (64.7% of the total FID area) and p-cymene (21.1%). Such a composition resembles a chemotype observed for R. tomentosum, a close relative found mainly in Europe and Asia, but has never been attributed to R. subarcticum. Growth inhibition assays against different strains of Plasmodium falciparum (3D7, Dd2), the parasite responsible for the most severe form of malaria, were conducted with either the R. subarcticum's essential oil or the isolated ascaridole. Our results show that the essential oil's biological activity can be attributed to ascaridole as its IC₅₀ is more than twice that of ascaridole [ascaridole's IC₅₀ values are 147.3 nM (3D7) and 104.9 nM (Dd2)].

Essential oils from Dysphania genus: Traditional uses, chemical composition, toxicology, and health benefits

The genus Dysphania belongs to the Amaranthaceae family and is known for its many health benefits. Therefore, it is commonly available worldwide and includes more than 47 species, five species have been mainly reported, and D. ambrosioides has been one of the most widely used plants for thousands of years as a remedy for a wide range of ailments. In recent investigations, the essential oils of the genus Dysphania have been examined for their antibacterial, antioxidant, and antiviral properties related to specific components such as terpenoid compounds that exhibit pharmacological activity. Moreover, some of Dysphania's compounds show a toxicological effect. Therefore, the objective of the study was to provide EO chemical composition and pharmacological data of the genus Dysphania.

Alpha-terthienyl increases filamentous actin of Entamoeba histolytica

This study aimed to know if alpha terthienyl (α-T) affects E. histolytica viability and to analyze its effect on the actin cytoskeleton. Trophozoites of E. histolytica HM1-IMSS were treated with α-T, then, cell viability and morphology were evaluated using tetrazolium salts and scanning electron microscopy, respectively; while actin filaments (F-actin) were stained with rhodamine-phalloidin, observed by confocal microscopy and quantified by fluorometry. Data showed that α-T inhibited cell viability of trophozoites (IC₅₀, 19.43 µg / mL), affected the cell morphology, and increased the F-actin in a dose-dependent manner. Production of reactive oxygen species and RhoA-GTP levels remained normal in α-T-treated amebas. Two inhibitors that affect the organization of the trophozoites cytoskeleton, one that interacts directly with actin, Cytochalasin D (CD), and one that affects the Rho signaling pathway by inhibiting the downstream effector Rock, Y27632, were tested. Y27632 did not affect the increase of polymerized actin observed with α-T, this compound partially ameliorates the potent disrupting effects of CD on actin filaments. Docking results suggest that α-T could be an antagonist of CD for the same interaction zone in actin, however, more studies are needed to define the action mechanism of this compound.

Antibacterial and Antioxidant Activity of Dysphania ambrosioides (L.) Mosyakin and Clemants Essential Oils: Experimental and Computational Approaches

Dysphania ambrosioides (L.) Mosyakin and Clemants, also known as Mexican tea, and locally known as Mkhinza, is a polymorphic annual and perennial herb, and it is widely used in folk medicine to treat a broad range of illnesses in Morocco. The aim of this study was to determine the phytochemical content and the antioxidant and the antibacterial properties of essential oils isolated from D. ambrosioides aerial components, growing in Eastern Morocco (Figuig). Hydrodistillation was used to separate D. ambrosioides essential oils, and the abundance of each phytocompound was determined by using Gas Chromatography coupled with Mass Spectrometry (GC-MS). In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and inhibition of β-carotene/linoleic acid bleaching assays were used to determine D. ambrosioides essential oils' antioxidant activity. The findings revealed relative antioxidative power and modest radical scavenging. The antibacterial activity of the essential oils was broad-spectrum, with Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis as the most susceptible strains tested. To elucidate the physicochemical nature, drug-likeness, and the antioxidant and antibacterial action of the identified phytocomponents, computational techniques, such as ADMET analysis, and molecular docking were used.

In-Vitro Effect of Kalanchoe daigremontiana and Its Main Component, Quercetin against Entamoeba histolytica and Trichomonas vaginalis

Background:

Parasitic infections represent one of the main public health problems in humans according to the WHO. Therefore, the need has arisen to find new treatments that can be used as an alternative cure to parasitosis. We aimed to investigate the in-vitro effects of the methanolic extract of Kalanchoe daigremontiana as well as its main component, quercetin against Entamoeba histolytica and Trichomonas vaginalis.

Methods:

For this purpose, the in-vitro activity of the methanol extract of K. daigremontiana also its main component, quercetin, against trophozoites of E. histolytica and T. vaginalis was evaluated, using the microassay technique. Furthermore, the antioxidant activity was determined. Finally, the cytotoxic and cytoprotective capacity was determined using the hemolysis technique.

Results:

The IC₅₀ indicated that quercetin significantly (P < 0.05) inhibited the growth rate of the trophozoite stage of E. histolytica and T. vaginalis in comparison to the methanolic extract of K. daigremontiana (KalL). Also, quercetin significantly (P < 0.05) was a better antioxidant as compared with the positive control. In the evaluation of cytotoxicity effects, it could be observed that KalL as compared with quercetin exhibited more cytotoxicity against human erythrocytes. Quercetin significantly (P < 0.001) exhibited better cytoprotective activity compared to KalL.

Conclusion:

Both K. daigremontiana methanolic extract and quercetin alone demonstrated high antiparasitic activity against E. histolytica and T. vaginalis. However, the in-vivo efficacy of K. daigremontiana and quercetin also requires to be evaluated using an animal model.

Ethnomedical uses, chemical constituents, and evidence-based pharmacological properties of Chenopodium ambrosioides L.: extensive overview

Background

The Chenopodium genus is a plant family widely spread worldwide that includes various plant species reputed to possess several medicinal virtues in folk medicines. Chenopodium ambrosioides L. is among the most used plants in traditional medicines worldwide. This review aimed to highlight ethnomedicinal uses, phytochemical status, and pharmacological properties of C. ambrosioides L.

Main body of the abstract

The analysis of relevant data highlights various ethnomedicinal uses against human and veterinary diseases in forty countries. Most indications consisted of gastrointestinal tract dysfunctioning troubles and worms parasitemia. Around 330 chemical compounds have been identified in different plant parts, especially in its essential oil fractions (59.84%). However, only a few compounds—mainly monoterpenes and glycosides—have been isolated and characterized. Experimental pharmacological studies validated a large scale of significant health benefits. It appeared that many monoterpenes are antioxidant, insecticidal, trypanocidal, analgesic, antifungal, anti-inflammatory, anti-arthritic, acaricidal, amoebicidal, anthelmintic, anticancer, antibacterial, antidiabetic, antidiarrheal, antifertility, antifungal, anti-leishmanial, antimalarial, antipyretic, antisickling, antischistosomal, antiulcer, anxiolytic, immunomodulatory, molluscicidal, and vasorelaxant agents.

Short conclusion

Thus, the Chenopodium ambrosioides species necessitates further chemical studies to isolate and characterize new bioactive secondary metabolites and pharmacological investigations to precise the mechanisms of action before clinical trials.

Averting transmission: A pivotal target to manage amoebiasis

Amoebiasis is a parasitic infectious disease caused by the enteric protozoan Entamoeba histolytica, a leading basis of deaths accounted to parasites, succeeding malaria and schistosomiasis. Conventional treatment methodologies used to deal with amoebiasis mainly rely on the administration of anti-amoebic compounds and vaccines but are often linked with substantial side-effects on the patient. Besides, cases of development of drug resistance in protozoans have been recorded, contributing further to the reduction in the efficiency of the treatment. Loopholes in the efficacious management of the disease call for the development of novel methodologies to manage amoebiasis. A way to achieve this is by targeting the essential metabolic processes of 'encystation' and 'excystation', and the associated biomolecules, thus interrupting the biphasic life cycle of the parasite. Technologies like the CRISPR-Cas9 system can efficiently be exploited to discover novel and essential molecules that regulate the protozoan's metabolism, while efficiently manipulating and managing the known drug targets, leading to an effective halt and forestall to the enteric infection. This review presents a perspective on these essential metabolic processes and the associated molecules that can be targeted efficaciously to prevent the transmission of amoebiasis, thus managing the disease and proving to be a fruitful endeavour.

In Vitro Effect of Methanolic Extract of Argemone mexicana against Trichomonas vaginalis

Infections caused by Trichomonas vaginalis in humans are one of the main public health problems caused by sexually transmitted diseases. Objective of this study was to evaluate potential biological activity of the medicinal plant Argemone mexicana (Mexican poppy) on T. vaginalis. Methanolic extracts of the stems and leaves of A. mexicana, and different fractions were prepared with solvents of different polarities. The extracts and functional groups were detected containing sterols, triterpenes, quinones, flavonoids and, alkaloids. Extracts from both the stems and leaves of A. mexicana inhibited the growth of T. vaginalis with half-maximal inhibitory concentration value of 70.6 and 67.2 μg/ml, respectively. In the active fractions, the most abundant compounds were berberine and jatrorrhizine, with presumed antiparasitic activity.

Amoebicidal activity of curcumin on Entamoeba histolytica trophozoites

Objectives

This study was undertaken to investigate the amoebicidal potential of curcumin on Entamoeba histolytica, as well as its synergistic effect with metronidazole.

Methods

Entamoeba histolytica trophozoites were exposed to 100, 200 and 300 μm of curcumin, for 6, 12 and 24 h. Consequently, the viability of cells was determined by trypan blue exclusion test. All specimens were further analysed by scanning electron microscopy. For drug combination experiment, the Chou-Talalay method was used.

Key findings

Curcumin affected the growth and cell viability in a time- and dose-dependent manner. The higher inhibitory effects were observed with 300 μm at 24 h; 65.5% of growth inhibition and only 28.8% of trophozoites were viable. Additionally, curcumin also altered adhesion and the morphology of the trophozoites. Scanning electron microscopy revealed treated trophozoites with damages on the membrane, size alterations and parasites with loss of cellular integrity. In addition, the combination of curcumin + metronidazole exhibited a synergistic effect; the activity of both drugs was improved.

Conclusions

This is the first report evaluating the effectiveness of curcumin against E. histolytica. Our results suggest that CUR could be considered for evaluation in future pharmacological studies as a promising amoebicidal agent or as complementary therapy.

Antiamoebic Activity of Adenophyllum aurantium (L.) Strother and Its Effect on the Actin Cytoskeleton of Entamoeba histolytica

In Mexico, the Adenophyllum aurantium (L.) Strother plant is consumed as an infusion to treat intestinal diseases such as amoebiasis, which is an endemic health problem in Mexico and other countries. However, the effect of A. aurantium on Entamoeba histolytica, the causative agent of amoebiasis, is unknown. An aerial part methanolic extract (AaMeA), a root methanolic extract (AaMeR) and a root ethyl acetate extract (AaEaR) were tested on E. histolytica trophozoites. AaMeA and AaMeR did not show antiproliferative activity; however, AaEaR exhibited an in vitro GI50 of 230 μg/ml, and it was able to inhibit the differentiation of Entamoeba invadens trophozoites into cysts. The intraperitoneal administration of AaEaR (2.5 or 5 mg) to hamsters that were infected with E. histolytica inhibited the development of amoebic liver abscesses in 48.5 or 89.0% of the animals, respectively. Adhesion to fibronectin and erythrophagocytosis were 28.7 and 37.5% inhibited by AaEaR, respectively. An ultrastructure analysis of AaEaR-treated trophozoites shows a decrease in the number of vacuoles but no apparent cell damage. Moreover, this extract affected the actin cytoskeleton structuration, and it prevented the formation of contractile rings by mechanism(s) that were independent of reactive oxygen species and RhoA activation pathways. (13)C NMR data showed that the major compounds in the AaEaR extract are thiophenes. Our results suggest that AaEaR may be effective in treatments against amoebiasis, nevertheless, detailed toxicity studies on thiophenes, contained in AaEaR, are required to avoid misuse of this vegetal species.

Simultaneous determination of ascaridole, p-cymene and α-terpinene in rat plasma after oral administration of Chenopodium ambrosioides L. by GC-MS

A sensitive and reliable GC-MS method was developed and validated for the simultaneous determination of ascaridole, p-cymene and α-terpinene in rat plasma using naphthalene as internal standard. The plasma samples were extracted with ethyl acetate. Chromatographic separation was carried out on a HP-5MS capillary analytical column (30 m × 0.25 mm, 0.25 µm) and detection was performed on a quadrupole mass spectrometer detector operated under selected ion monitoring mode. The method showed excellent linearity over the investigated concentration range (r > 0.99) with the limit of quantitation down to 50, 10 and 5 ng/mL for ascaridole, p-cymene and α-terpinene, respectively. The intra-day and inter-day precisions (RSD) were <11.3%, and the accuracy was between 90.7 and 113.8%. The method was successfully applied to investigate the pharmacokinetics of Chenopodium ambrosioides L. following oral administration to rats.