Anti-Trypanosoma cruzi activity of 10 medicinal plants used in northeast Mexico

Cytotoxic, Anti-Hemolytic, and Antioxidant Activities of Ruta chalepensis L. (Rutaceae) Extract, Fractions, and Isolated Compounds

Ruta chalepensis is an herb used to treat various ailments, and its potential cytotoxic effects on different tumor cell lines have been extensively studied. The present study aimed to evaluate the cytotoxic activity of R. chalepensis methanol extract (RCME), sub-partitions obtained from solvents of increasing polarity, and major compounds, as well as their hemolytic, anti-hemolytic, and antioxidant potential. The in vitro cytotoxic activity against the human hepatocarcinoma (HEP-G2) and the murine lymphoma cell line (L5178Y-R) was evaluated using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, whereas selectivity indices (SIs) were determined by comparing cytotoxicity against normal African green monkey kidney cells (VERO) and human peripheral blood mononuclear cells (PBMC). Hemolytic and anti-hemolytic activities were evaluated on human erythrocytes. The most effective cytotoxic treatment was evaluated for nitric oxide release by J774A.1 macrophages. Antioxidant activity of R. chalepensis material was also determined. Results showed that RCME produced significant (p < 0.05) cytotoxicity in HEP-G2 (IC₅₀ = 1.79 µg/mL) and L5178Y-R (IC₅₀ = 1.60 µg/mL) cells and exhibited high SIs (291.50 and 114.80, respectively). In addition, the n-hexane fraction (RCHF) showed an IC₅₀ of 18.31 µg/mL in HEP-G2 cells and an SI of 9.48 in VERO cells, whereas the chloroform fraction (RCCF) evidenced an IC₅₀ of 1.60 µg/mL in L5178Y-R cells and an SI of 34.27 in PBMC cells. Chalepensin (CHL), rutamarin (RTM), and graveolin (GRV), which are major components of R. chalepensis, showed high activity against L5178Y-R cells, with IC₅₀ of 9.15, 15.13 and SI of 45.08 µg/mL, respectively. In addition, CHL, RTM, and GRV showed SIs of 24.76, 9.98, and 3.52, respectively, when compared with PBMC cells. RCME at concentrations of 125 µg/mL and 250 µg/mL, significantly (p < 0.05) decreased nitrite production in J774A.1 cells, when exposed to lipopolysaccharide. This study demonstrated that RCME showed significant cytotoxic activity against HEP-G2 and L5178Y-R cells, without affecting normal VERO, PBMC, and J774A.1 cells.

Ethnobotany, Biological Activities and Phytochemical Compounds of Some Species of the Genus Eryngium (Apiaceae), from the Central-Western Region of Mexico

There are approximately 250 species of Eryngium L. distributed throughout the world, with North America and South America being centers of diversity on this continent. In the central-western region of Mexico there may be around 28 species of this genus. Some Eryngium species are cultivated as leafy vegetables, ornamental, and medicinal plants. In traditional medicine they are used to treat respiratory and gastrointestinal conditions, diabetes, and dyslipidemia, among others. This review addresses the phytochemistry and biological activities, as well as traditional uses, distribution, and characteristics of the eight species of Eryngium reported as medicinal in the central-western region of Mexico: E. cymosum, E. longifolium, E. fluitans (or mexicanum), E. beecheyanum, E. carlinae, E. comosum, E. heterophyllum, and E. nasturtiifolium. The extracts of the different Eryngium spp. have shown biological activities such as hypoglycemic, hypocholesterolemic, renoprotective, anti-inflammatory, antibacterial, and antioxidant, among others. E. carlinae is the most studied species, and phytochemical analyses, performed mainly by high-performance liquid chromatography (HPLC) and gas chromatography coupled with mass spectrometry (GC-MS), have shown its content of terpenoids, fatty acids, organic acids, phenolic acids, flavonoids, sterols, saccharides, polyalcohols, and aromatic and aliphatic aldehydes. According to the results of this review on Eryngium spp., they constitute a relevant alternative as a source of bioactive compounds for pharmaceutical, food, and other industries. However, there is a lot of research to be conducted regarding phytochemistry, biological activities, cultivation, and propagation, in those species with few or no reports.

Hydroalcoholic extract of Haematoxylum brasiletto protects Caenorhabditis elegans from cadmium-induced toxicity

Background

H. brasiletto is used in popular culture due to its therapeutic properties, including antioxidant, anti-inflammatory and antiproliferative properties, although little is known about its role as a protector against metal toxicity. This study aimed to investigate the chemical composition and efficacy of the hydroalcoholic extract from H. brasiletto (HAE-Hbrasiletto) collected in northern Colombia to defend against cadmium (Cd)-induced toxicity.

Methods

Phytochemical characterization was performed using HPLC-ESI-QTOF. Caenorhabditis elegans was employed to assess the shielding effect of HAE-Hbrasiletto against Cd toxicity in vivo, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was utilized to measure radical scavenging activity.

Results

The main secondary metabolites identified by HPLC-ESI-QTOF in the extracts were hematoxylins (brazilein and hematein) and protosappanins (protosappanin A, B and C, 10-O-methylprotosappanin B, and protosappanin A dimethyl acetal). The HAE-Hbrasiletto elicited low lethality in N2 worms and significantly reduced the Cd-induced death of the nematodes. It also improved Cd-induced motility inhibition, as well as body length and reproduction reduction provoked by the heavy metal. The extract displayed a good capacity to halt Cd-induced DAF-16 translocation. As this last process was associated with lethality (r = 0.962, p < 0.01), the antioxidant properties of the extract may contribute to ameliorating tissue damage induced by oxidative stress from Cd exposure.

Conclusion

HAE-Hbrasiletto has remarkable properties to protect against Cd-induced toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03654-6.

Most secondary metabolites tentatively identified in H. brasiletto are homoisoflavones.

Hidroalcoholic extract of H. brasiletto protects C. elegans from Cd toxicity

The extract diminished Cd-induced damage to reproduction, growth, and locomotion.

Cd-induced oxidative stress and translocation of DAF-16 are blocked by the extract.

In Vitro Cytotoxic Activity of Methanol Extracts of Selected Medicinal Plants Traditionally Used in Mexico against Human Hepatocellular Carcinoma

Medicinal plants are traditionally used in Mexico to treat diseases such as cancer. The present study aimed to evaluate the cytotoxic, antioxidant, and anti-hemolytic activity of 15 plants of ethnopharmacological use in Mexico. For this, plant methanol extracts were prepared by the Soxhlet method, after which their cytotoxic activity was evaluated against human hepatocellular carcinoma (HEP-G2) and monkey kidney epithelial (Vero) cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction colorimetric assay. The selectivity index (SI) of each extract was then determined by the IC₅₀ ratio of normal to tumor cells. We showed that Ruta chalepensis extract possessed an IC₅₀ of 1.79 µg/mL and 522.08 µg/mL against HEP-G2 and Vero cells, respectively, resulting in an SI of 291.50. Furthermore, antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging technique, where the best antioxidant potential was shown by the Heterotheca inuloides extract (IC₅₀ = 19.24 µg/mL). Furthermore, the hemolytic potential was determined against human erythrocytes, which showed that the extracts with the highest anti-hemolytic activity were Smilax aspera (IC₅₀ = 4.41 µg/mL) and Amphipterygium adstringens (IC₅₀ = 5.35 µg/mL). In conclusion, we observed that R. chalepensis methanol extract possesses cytotoxic activity against HEP-G2 cells, without affecting non-tumorigenic Vero cells. Our results indicated the antitumor potential of medicinal plants used in Mexico.

Evaluation of the In Vitro Antiparasitic Effect of the Essential Oil of Cymbopogon winterianus and Its Chemical Composition Analysis

Cymbopogon winterianus, known as “citronella grass”, is an important aromatic and medicinal tropical herbaceous plant. The essential oil of C. winterianus (EOCw) is popularly used to play an important role in improving human health due to its potential as a bioactive component. The present study aimed to identify the components of the essential oil of C. winterianus and verify its leishmanicidal and trypanocidal potential, as well as the cytotoxicity in mammalian cells, in vitro. The EOCw had geraniol (42.13%), citronellal (17.31%), and citronellol (16.91%) as major constituents. The essential oil only exhibited significant cytotoxicity in mammalian fibroblasts at concentrations greater than 250 μg/mL, while regarding antipromastigote and antiepimastigote activities, they presented values considered clinically relevant, since both had LC50 < 62.5 μg/mL. It can be concluded that this is a pioneer study on the potential of the essential oil of C. winterianus and its use against the parasites T. cruzi and L. brasiliensis, and its importance is also based on this fact. Additionally, according to the results, C. winterianus was effective in presenting values of clinical relevance and low toxicity and, therefore, an indicator of popular use.

The genus Schinus (Anacardiaceae): a review on phytochemicals and biological aspects

The genus Schinus belongs to family 'Anacardiaceae' and includes about 29 species originating from South America, distributed to Peru, Chile, Argentina, Brazil and Paraguay and cultivated in Egypt. Traditionally, Schinus plants are used to alleviate several and diverse diseases including rheumatism, hypertension, ulcers, gastric distress, menstrual disorders, gonorrhea, bronchitis, gingivitis, conjunctivitis, dysentery, wounds, urinary tract, and eye infections. Several phytochemical studies on the Schinus plants revealed presence of diverse bioactive compounds such as flavonoids, bioflavonoids, phenolic acids, tannins, catechins, terpenoids and essential oils. Besides, some Schinus species and their isolated active compounds showed important biological activities such as antibacterial, antifungal, insecticidal, antiparasitic, analgesic, cytotoxic, antitumor, antioxidant, antihypertensive, anti-inflammatory, antimycobacterial, anti-Parkinson, anti-allergic, antiviral, wound healing, chemoprotective, anthelmintic and hepatoprotective. This review attempts to summarize the phytochemical profile and biological activities of Schinus species that could guide researchers to undertake further investigation.

Anti-trypanosomal screening of Salvadoran flora

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and in Central America, it is considered one of the four most infectious diseases. This study aimed to screen the anti-trypanosomal activity of plant species from Salvadoran flora. Plants were selected through literature search for plants ethnobotanically used for antiparasitic and Chagas disease symptomatology, and reported in Museo de Historia Natural de El Salvador (MUHNES) database. T. cruzi was incubated for 72 h with 2 different concentrations of methanolic extracts of 38 species, among which four species, Piper jacquemontianum, Piper lacunosum, Trichilia havanensis, and Peperomia pseudopereskiifolia, showed the activity (≤ 52.0% viability) at 100 µg/mL. Separation of the methanolic extract of aerial parts from Piper jacquemontianum afforded a new flavanone (4) and four known compounds, 2,2-dimethyl-6-carboxymethoxychroman-4-one (1), 2,2-dimethyl-6-carboxychroman-4-one (2), cardamomin (3), and pinocembrin (5), among which cardamomin exhibited the highest anti-trypanosomal activity (IC₅₀ = 66 µM). Detailed analyses of the spectral data revealed that the new compound 4, named as jaqueflavanone A, was a derivative of pinocembrin having a prenylated benzoate moiety at the 8-position of the A ring.

Advances in the treatment of Chagas disease: Promising new drugs, plants and targets

Chagas disease, caused by Trypanosoma cruzi, is treated with only two drugs; benznidazole and nifurtimox. These drugs have some disadvantages, including their efficacy only in the acute or early infection phases, adverse effects during their use, and the resistance that the parasite has developed to their activity. Therefore, it is necessary to identify new, safe and effective therapeutic alternatives to treat Chagas disease, though governments and the pharmaceutical industry have shown a lack of interest in contributing to this solution. Institutions and research groups on the other hand have worked on some strategies that can help to address the problem. Some of these include the modification of conventional drug dosages, drug repurposing, and combined therapy. Plants and derived compounds with antiparasitic effects have also been studied, taking advantage of traditional medicinal knowledge. Others have studied the parasite to identify essential genes that can be used as therapeutic targets to design new, targeted drugs. Some of these studies have generated promising results, but few reach clinical phase studies. Institutions and research groups should be encouraged to unify efforts and cover all aspects of drug development according to resources and knowledge availability. In the end, this exchange of knowledge would lead to the development of new therapeutic alternatives to treat Chagas disease and benefit the populations it affects.

Preliminary chemical characterization of ethanolic extracts from Colombian plants with promising anti - Trypanosoma cruzi activity

Chagas disease is caused by Trypanosoma cruzi, and it is an important cause of morbidity and mortality in Latin America. There are no vaccines, and the chemotherapy available to treat this infection has serious side effects. In a search for alternative treatments, we determined the in vitro susceptibility of epimastigote and trypomastigote forms of T. cruzi and the cytotoxic effects on peripheral blood mononuclear cells (PBMCs) of ethanolic extracts obtained from six different plant species. The ethanolic extracts of Ageratina vacciniaefolia, Clethra fimbriata and Siparuna sessiliflora showed antiprotozoal activity against epimastigotes and low cytotoxicity in mammalian cells. However, only the ethanolic extract of C. fimbriata showed activity against T. cruzi trypomastigotes, and it had low cytotoxicity in PBMCs. An analysis on the phytochemical composition of C. fimbriata extract showed that its metabolites were primarily represented by two families of compounds: flavonoids and terpenoids. Lastly, we analyzed whether the A. vacciniaefolia, C. fimbriata, or S. sessiliflora ethanolic extracts induced IFN-γ or TNF-α production. Significantly, ethanolic extracts of C. fimbriata induced TNF-α production and S. sessiliflora induced both cytokines. In addition, C. fimbriata and S. sessiliflora induced the simultaneous secretion of IFN-γ and TNF-α in CD8⁺ T cells. The antiprotozoal and immunomodulatory activity of C. fimbriata may be related to the presence of flavonoid and triterpene compounds in the extract. Thus, these findings suggest that C. fimbriata may represent a valuable source of new bioactive compounds for the therapeutic treatment of Chagas disease that combines trypanocidal activity with the capacity to boost the immune response.

Expanding the scope of synthetic 1,2,4-trioxanes towards Trypanosoma cruzi and Leishmania donovani

A series of synthetic 1,2,4-trioxanes related to artemisinin was tested against L. donovani and T. cruzi parasites. This screening identified some active compounds, with key common structural features. Interestingly, these selected trioxanes were efficient against both parasites, and achieved antiparasitic activities comparable or superior than those presented by the corresponding reference drugs, artemisinin and artesunate. This study represents the first example of synthetic trioxanes evaluated on T. cruzi and provides possible candidates for developing new drugs for the treatment of leishmaniasis and Chagas disease.

Genus Ruta: A natural source of high value products with biological and pharmacological properties

ETHNOPHARMACOLOGICAL RELEVANCE

Ruta genus is constituted by ten species, of which the most commonly described are R. chalepensis and R. graveolens. Ruta plants are perennial shrubs belonging to the family Rutaceae, which are traditionally used in folk medicine, since ancient times mostly for the treatment of various ailments of the womb.

AIM OF THE STUDY

To provide a review of the different uses of Ruta species in traditional medicine, as well as, on their multifactorial biological and pharmacological properties.

MATERIAL AND METHODS

A search of the literature on genus Ruta and Ruta species was performed using various scientific databases and search engines and the information of articles were reviewed and compiled.

RESULTS

Different parts of the plants belonging to Ruta genus are used in folk medicine to treat a wide range of different diseases. The principal use of these is in gynaecological field, but the treatment of pain, fever, nausea, inflammation, infections, nervous disorders, among others, are also described. These plants have been used to fertility regulation, as anti-fertility agent, to control menstrual flux and bleedings, as abortifacient and as contraceptive. The phytochemical composition of these plants consists mainly in essential oil (EO), but phenolic compounds were also reported, like coumarins and flavonoids, as well as alkaloids. Ruta species products like extracts and EOs have shown broad pharmacological activities, such as antimicrobial and antifungal activities, as well as, antiviral and antiparasitic. Moreover, Ruta plants products present antioxidant, neuroprotective, anti-inflammatory, anti-cancer and anti-diabetic activities and demonstrated contraceptive and abortifacient effects. These plants were also tested to be used for non-therapeutic approaches, as bio-insecticides in the control of different insect pests showing to be able to reduce infestation.

CONCLUSIONS

Ruta species could be a potential source of natural products with biological activities. Ruta extracts, essential oils and isolated compounds have shown a diverse potential for use in the treatment of different diseases, as well as, for pests control, contributing to the valorisation of these plants. Nonetheless, this review indicates that more studies are needed to demonstrate the full potential of Ruta species, and to further explore the toxicology and safety of these plants.

Microalgae extracts: Potential anti-Trypanosoma cruzi agents?

INTRODUCTION

Chagas disease, caused by the protozoan parasiteTrypanosoma cruzi, has no effective treatment available. On the other hand, microalgae are aquatic organisms that constitute an interesting reservoir of biologically active metabolites. Moreover, some species of green and red algae present anti-protozoan activity. Our aim was to study the antiparasitic effects of aqueous, methanolic and ethanolic extracts from different microalgae.

METHODS AND RESULTS

Our results show that the methanolic extracts of S. obliquus and T. suecica as well as the ethanolic extracts of C. reinhardtii and T. suecica present trypanocidal activity on the infective extracellular trypomastigotes and intracellular amastigotes. In addition, the ethanolic extract of C. reinhardtii potentiates the activity of the conventional antichagasic drug nifurtimox. In order to identify some potential compounds with trypanocidal activity, we performed a phytochemical screening analyzing the presence of phenolic compounds, pigments and terpenoids.

CONCLUSION

The different microalgae extracts, particularly the ethanolic extract ofC. reinhardtii, are promising potential candidates for the development of future natural antichagasic drugs.

Identification and Localization of the First Known Proteins of the Trypanosoma cruzi Cytostome Cytopharynx Endocytic Complex

The etiological agent of Chagas disease, Trypanosoma cruzi, is an obligate intracellular parasite that infects an estimated 7 million people in the Americas, with an at-risk population of 70 million. Despite its recognition as the highest impact parasitic infection of the Americas, Chagas disease continues to receive insufficient attention and resources in order to be effectively combatted. Unlike the other parasitic trypanosomatids that infect humans (Trypanosoma brucei and Leishmania spp.), T. cruzi retains an ancestral mode of phagotrophic feeding via an endocytic organelle known as the cytostome-cytopharynx complex (SPC). How this tubular invagination of the plasma membrane functions to bring in nutrients is poorly understood at a mechanistic level, partially due to a lack of knowledge of the protein machinery specifically targeted to this structure. Using a combination of CRISPR/Cas9 mediated endogenous tagging, fluorescently labeled overexpression constructs and endocytic assays, we have identified the first known SPC targeted protein (CP1). The CP1 labeled structure co-localizes with endocytosed protein and undergoes disassembly in infectious forms and reconstitution in replicative forms. Additionally, through the use of immunoprecipitation and mass spectrometry techniques, we have identified two additional CP1-associated proteins (CP2 and CP3) that also target to this endocytic organelle. Our localization studies using fluorescently tagged proteins and surface lectin staining have also allowed us, for the first time, to specifically define the location of the intriguing pre-oral ridge (POR) surface prominence at the SPC entrance through the use of super-resolution light microscopy. This work is a first glimpse into the proteome of the SPC and provides the tools for further characterization of this enigmatic endocytic organelle. A better understanding of how this deadly pathogen acquires nutrients from its host will potentially direct us toward new therapeutic targets to combat infection.

Structural Elucidation and Cytotoxicity of a New 17-Membered Ring Lactone from Algerian Eryngium campestre

The chemical composition of a hexanic extract of Eryngium campestre, obtained from its aerial parts, was investigated by GC-FID, GC/MS, HRMS, NMR and VCD analyses. The main compounds were germacrene D (23.6%), eudesma-4(15)-7-dien-1-β-ol (8.2%) and falcarindiol (9.4%), which are associated with a new uncommon and naturally found 17-membered ring lactone. This 17-membered ring features conjugated acetylenic bonds, named campestrolide (23.0%). The crude extract showed moderate antitrypanosomal (Trypanosoma brucei brucei), antileishmanial (Leishmania mexicana mexicana) and anticancer (cancerous macrophage-like murine cells) activities, and also displayed cytotoxicity, (human normal fibroblasts) in similar concentration ranges (IC₅₀ = 3.0, 3.9, 4.0 and 4.4 µg/mL respectively). Likewise, campestrolide displayed low activity on all tested cells (IC₅₀: 12.5–19.5 µM) except on Trypanosoma, on which it was very active and moderately selective (IC₅₀ = 2.2 µM. SI= 8.9). In conclusion, the new compound that has been described, displaying a singular structure, possesses interesting antitrypanosomal activity that should be further investigated and improved.

Acaricidal effect of Schinus molle (Anacardiaceae) essential oil on unengorged larvae and engorged adult females of Rhipicephalus sanguineus (Acari: Ixodidae)

The current concern about resistance to acaricides and the impact of toxic waste on the environment has led to the search of vegetal alternatives in the control of the brown tick of the dog Rhipicephalus sanguineus. Schinus molle L. (Anacardiaceae) derivatives have been associated with insecticidal, antimicrobial and antiprotozoal activities and essential oil showed to be lethal to R. microplus larvae. This study aimed at evaluating the acaricidal effect of essential oil of S. molle (EO_Sm) on engorged adult females and larval stages of R. sanguineus. One-hundred engorged females were obtained from the ears, interdigital spaces, neck, groin and base of the tail of two cross-bred dogs. The larvae package test was accomplished with 21-day-old larvae and five concentrations (v/v) of EO_Sm (0.125, 0.25, 0.50, 1 and 2%) in an anionic detergent, a synthetic acaricide (cypermethrin) and detergent and deionized water as controls. The immersion adult test was carried out with nine concentrations (0.125, 0.25, 0.50, 1, 2, 4, 8, 16, 20%) of the EO_Sm. At the concentration of 2%, EO_Sm caused 99.3% of larval mortality. In adults, inhibition of oviposition, egg hatching (EH) and reproductive efficiency (RE) values were dose-dependent from 4 to 20% EO_Sm; the lowest values of EH (29.62) and RE (22.61) were achieved with 20% EO_Sm. Strong and negative correlations were found between concentration of EO_Sm and EH (r = - 0.948) and between concentration of EO_Sm and RE (r = - 0.985). This study demonstrated for the first time the acaricidal effect of EO_Sm on larvae and reproductive parameters of engorged adult females of R. sanguineus.

The activity of Artemisia spp. and their constituents against Trypanosomiasis

BACKGROUND

Trypanosomiasis belongs to the neglected tropical diseases. Although standard therapies are available, the safety and efficacy of current synthetic drugs are limited due to the development of drug resistance and adverse side effects.

PURPOSE

Artemisia annua and artemisinin are not only active against Plasmodia, but also other protozoa. Therefore, we reviewed the literature on species of the genus Artemisia and their phytochemicals regarding their activity against trypanosomes.

STUDY DESIGN

A PubMed search for "Artemisia/Artemisinin and Trypanosoma" has been conducted for literature until December 2017.

RESULTS

Interestingly, not only A. annua L. and its active principle, artemisinin revealed inhibitory activity towards trypanosomes. Other Artemisia species (A. absinthium, A. abyssinica, A. afra, A. douglasia, A. elegantissima, A. maciverae, A. mexicana, and A. roxburghiana) also inhibited T. brucei, T. cruzi, or T. congolense. The plants contained numerous chemical constituents including 3',4'-dihydroxybonanzin, apigenin, betulinic acid, bonanzin, dehydroleucodine, dihydroluteolin, dracunculin and bis-dracunculin, helenalin, nepetin, scoparol, scopoletin, stigmasterol, (Z)-p‑hydroxy cinnamic acid, β-sitosterol and others. In addition to artemisinin from A. annua, artemether and artesunate, further novel artemisinin derivatives and nanotechnological preparations may also be useful to combat Trypanosoma infections.

CONCLUSION

There are numerous results reporting on the anti-trypanosomal activity the genus Artemisia, artemisinin and its derivatives and other phytochemicals from Artemisia species. This field of research is, however, still in its infancy and more intensive research is required to explore the full potential of diverse Artemisia species and their chemical ingredients for eradication of trypanosomal infections.

Trypanocidal activity of polysaccharide extract from Genipa americana leaves

ETHNOPHARMACOLOGICAL RELEVANCE

The parts of the Genipa americana (Rubiaceae) tree, also known as "jenipapo" or "jenipapeiro", has been used in traditional Medicine in parasitic and bacterial infections. Thus, the experimental evolution of the antiparasitic activity of polysaccharide extracts from Genipa americana leaves, and correlation with antiparasitic and popular use is important.

AIM OF THE STUDY

To evaluate the effect of polysaccharide extract obtained from Genipa americana leaves on all Trypanosoma cruzi (Y strain: benznidazole-resistant) developmental forms, a protozoan that causes Chagas' disease.

MATERIALS AND METHODS

An extract rich in polysaccharides was obtained from the leaves of Genipa americana (GaEPL) by associating depigmentation in methanol followed by extraction of polysaccharides in NaOH and precipitation with ethanol. Cytotoxicity to mammalian cells (LLC-MK2) was determined using an MTT assay. Antiparasitic activity was evaluated against epimastigote, trypomastigote and amastigote forms of T. cruzi. Cell-death mechanism was determined in epimastigote forms by flow cytometry analysis after FITC-annexin V (Ax), 7-AAD, and H2DCFDA staining. Striking morphological changes were observed by scanning electron microscope.

RESULTS

GaEPL (6.5% yield; 54.6% total carbohydrate; 21.1% uronic acid and 12% protein), inhibited all T. cruzi developmental forms, epimastigotes after periods of 24h (IC₅₀ = 740 ± 0.075µg/mL), 48h (IC₅₀ = 710 ± 0.053µg/mL) and 72h (IC₅₀ = 870 ± 0.052µg/mL) of incubation; trypomastigotes (IC₅₀ = 470 ± 0.082µg/mL) after periods of 24h and intracellular amastigotes (IC_50/2 = 235 or IC₅₀ = 470µg/mL) after periods of 24 and 48h of incubation, with no toxicity on LLC-MK2 cells at the used concentrations. Analysis of the possible action mechanism in the parasites suggested cell death by necrosis with the involvement of reactive oxygen species (ROS). The scanning electron microscopy (SEM) confirmed T. cruzi death by necrosis.

CONCLUSIONS

GaEPL showed significant activity against the epimastigote, trypomastigote and amastigote forms of T. cruzi, strain Y, suggesting cell death by necrosis with involvement of reactive oxygen species.

In vitro anthelmintic and cytotoxic activities of extracts of Persea willdenovii Kosterm (Lauraceae)

This study describes the effects of extracts and fractions of Persea willdenovii leaves against goat gastrointestinal nematodes and their cytotoxicity on Vero cells. The in vitro ovicidal and larvicidal activities of the crude ethanolic, hexane, ethyl acetate (EAE), butanolic and residual hydroethanolic extracts were assessed through the inhibition of egg hatching and larval motility assays. The most active extract (EAE) was then fractionated by chromatography in an open column containing silica gel, to furnish six fractions (Fr1–Fr6), which were also tested. The cytotoxicity of active extracts and fractions was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue exclusion assay. The EAE and two fractions (Fr1 and Fr2) showed inhibitory activity in the egg hatching of gastrointestinal nematodes of goats in a concentration-dependent manner. The effective concentrations for 50% inhibition (EC50) of egg hatching were 2.3, 0.12 and 2.94 mg/ml for EAE, Fr1 and Fr2, respectively. All extracts and fractions were not effective in inhibiting 50% of motility of infective larvae. EAE and Fr2 had IC50 values (50% inhibitory concentration) of 4.95 and 2.66 mg/ml, respectively. Fr1 showed a slight cytotoxic effect (cellular inviability <30%) only after 48 h of treatment (MTT test). Gas chromatography–mass spectrometry (GC–MS) analysis showed the presence of six fatty acid ethyl esters, a fatty acid methyl ester and a long-chain ketone in the most active fraction. These constituents identified in P. willdenovii can be related to the high ovicidal activity and relatively non-toxic effect of the extracts.

In vitro antileishmanial activity of Mexican medicinal plants

Aim of the study

To evaluate the anti-leishmanial activity and cytotoxicity of aqueous and organic extracts of ten plants used in Mexican traditional medicine as anti-parasitics.

Materials and methods

For the organic extracts, plant material was macerated in dichloromethane (CH₂Cl₂) and dichloromethane/methanol (CH₂Cl₂/MeOH) (1:1) during two weeks; the aqueous extracts were prepared by infusion. The extracts were tested against promastigotes and intracellular amastigotes of Leishmania amazonensis. The cytotoxicity was assayed in parallel on peritoneal macrophages of BALB/c mice.

Results

Four of the thirty extracts tested were active and selective against L. amazonensis promastigotes: Schinus molle (CH₂Cl₂ and CH₂Cl₂/MeOH), Lantana camara (CH₂Cl₂) and Prosopis laevigata (aqueous). These extracts had a median inhibitory concentration (IC₅₀) against intracellular amastigotes under 50 μg/mL and a selectivity index (SI) higher than 5, which indicates that they constitute valuable candidates to obtain secondary metabolites with leishmanicidal activity.

Conclusions

The results derived from this study indicate that L. camara, P. laevigata, and S. molle might provide interesting new leads for the development of antileishmanial drugs.

Differential expression on mitochondrial tryparedoxin peroxidase (mTcTXNPx) in Trypanosoma cruzi after ferrocenyl diamine hydrochlorides treatments

Resistance to benznidazole in certain strains of Trypanosoma cruzi may be caused by the increased production of enzymes that act on the oxidative metabolism, such as mitochondrial tryparedoxin peroxidase which catalyses the reduction of peroxides. This work presents cytotoxicity assays performed with ferrocenyl diamine hydrochlorides in six different strains of T. cruzi epimastigote forms (Y, Bolivia, SI1, SI8, QMII, and SIGR3). The last four strains have been recently isolated from triatominae and mammalian host (domestic cat). The expression of mitochondrial tryparedoxin peroxidase was analyzed by the Western blotting technique using polyclonal antibody anti mitochondrial tryparedoxin peroxidase obtained from a rabbit immunized with the mitochondrial tryparedoxin peroxidase recombinant protein. All the tested ferrocenyl diamine hydrochlorides were more cytotoxic than benznidazole. The expression of the 25.5 kDa polypeptide of mitochondrial tryparedoxin peroxidase did not increase in strains that were more resistant to the ferrocenyl compounds (SI8 and SIGR3). In addition, a 58 kDa polypeptide was also recognized in all strains. Ferrocenyl diamine hydrochlorides showed trypanocidal activity and the expression of 25.5 kDa mitochondrial tryparedoxin peroxidase is not necessarily increased in some T. cruzi strains. Most likely, other mechanisms, in addition to the over expression of this antioxidative enzyme, should be involved in the escape of parasites from cytotoxic oxidant agents.

Effects of a novel β-lapachone derivative on Trypanosoma cruzi: Parasite death involving apoptosis, autophagy and necrosis

Natural products comprise valuable sources for new antiparasitic drugs. Here we tested the effects of a novel β-lapachone derivative on Trypanosoma cruzi parasite survival and proliferation and used microscopy and cytometry techniques to approach the mechanism(s) underlying parasite death. The selectivity index determination indicate that the compound trypanocidal activity was over ten-fold more cytotoxic to epimastigotes than to macrophages or splenocytes. Scanning electron microscopy analysis revealed that the R72 β-lapachone derivative affected the T. cruzi morphology and surface topography. General plasma membrane waving and blebbing particularly on the cytostome region were observed in the R72-treated parasites. Transmission electron microscopy observations confirmed the surface damage at the cytostome opening vicinity. We also observed ultrastructural evidence of the autophagic mechanism termed macroautophagy. Some of the autophagosomes involved large portions of the parasite cytoplasm and their fusion/confluence may lead to necrotic parasite death. The remarkably enhanced frequency of autophagy triggering was confirmed by quantitating monodansylcadaverine labeling. Some cells displayed evidence of chromatin pycnosis and nuclear fragmentation were detected. This latter phenomenon was also indicated by DAPI staining of R72-treated cells. The apoptotis induction was suggested to take place in circa one-third of the parasites assessed by annexin V labeling measured by flow cytometry. TUNEL staining corroborated the apoptosis induction. Propidium iodide labeling indicate that at least 10% of the R72-treated parasites suffered necrosis within 24 h. The present data indicate that the β-lapachone derivative R72 selectively triggers T. cruzi cell death, involving both apoptosis and autophagy-induced necrosis.

Trypanocidal action of Lippia alba and Lippia origanoides essential oils against Trypanosoma evansi in vitro and in vivo used mice as experimental model

Parasitic diseases have an enormous health and economic impact and are a particular problem in tropical regions of the world. Disease caused by protozoa, such as trypanosomiasis, are the cause of most parasite related morbidity and mortality. Thus, the aim of this study was to verify the trypanocidal effectiveness of Lippia alba and Lippia origanoides against Trypanosoma evansi in vitro and in vivo. L. alba and L. origanoides were used in vitro on trypomastigotes at different concentrations (0.5, 1.0 and 2.0 %) and exposure times (0, 1, 3, 6 and 9 h). The three concentrations tested showed trypanocidal activity in vitro, completely eliminating the parasites in small concentration after 6 h of assay. In vivo tests were performed using mice as the experimental model. T. evansi infected mice were treated with L. alba and L. origanoides with dose of 1.5 mL kg^-1 during 5 days. These protocols did not provide curative efficacy, however the mice treated with L. origanoides showed a significant increase in the longevity when compared to control group. Active compounds present in essential oils, such as L. origanoides, may potentiate the treatment of trypanosomosis when associated with other trypanocidal drugs.

Toxicity and Loss of Mitochondrial Membrane Potential Induced by Alkyl Gallates in Trypanosoma cruzi

American trypanosomiasis or Chagas disease is a debilitating disease representing an important social problem that affects, approximately, 10 million people in the world. The main aggravating factor of this situation is the lack of an effective drug to treat the different stages of this disease. In this context, the search for trypanocidal substances isolated from plants, synthetic or semi synthetic molecules, is an important strategy. Here, the trypanocidal potential of gallates was assayed in epimastigotes forms of T. cruzi and also, the interference of these substances on the mitochondrial membrane potential of the parasites was assessed, allowing the study of the mechanism of action of the gallates in the T. cruzi organisms. Regarding the preliminary structure-activity relationships, the side chain length of gallates plays crucial role for activity. Nonyl, decyl, undecyl, and dodecyl gallates showed potent antitrypanosomal effect (IC₅₀ from 1.46 to 2.90 μM) in contrast with benznidazole (IC₅₀ = 34.0 μM). Heptyl gallate showed a strong synergistic activity with benznidazole, reducing by 10⁵-fold the IC₅₀ of benznidazole. Loss of mitochondrial membrane potential induced by these esters was revealed. Tetradecyl gallate induced a loss of 53% of the mitochondrial membrane potential, at IC₅₀ value.

Antiprotozoal activity against Entamoeba histolytica of plants used in northeast Mexican traditional medicine. Bioactive compounds from Lippia graveolens and Ruta chalepensis

Amoebiasis caused by Entamoeba histolytica is associated with high morbidity and mortality is becoming a major public health problem worldwide, especially in developing countries. Because of the side-effects and the resistance that pathogenic protozoa build against the standard antiparasitic drugs, e.g., metronidazole, much recent attention has been paid to plants used in traditional medicine around the world in order to find new antiprotozoal agents. We collected 32 plants used in Northeast Mexican traditional medicine and the methanolic extracts of these species were screened for antiprotozoal activity against E. histolytica trophozoites using in vitro tests. Only 18 extracts showed a significant inhibiting activity and among them six plant extracts showed more than 80% growth inhibition against E. histolytica at a concentration of 150 µg/mL and the IC50 values of these extracts were determined. Lippia graveolens Kunth and Ruta chalepensis Pers. showed the more significant antiprotozoal activity (91.54% and 90.50% growth inhibition at a concentration of 150 µg/mL with IC50 values of 59.14 and 60.07 µg/mL, respectively). Bioassay-guided fractionation of the methanolic extracts from these two plants afforded carvacrol (1) and chalepensin (2), respectively, as bioactive compounds with antiprotozoal activity.