In vitro anti-Acanthamoeba activity of flavonoid glycosides isolated from Delphinium gracile, D. staphisagria, Consolida oliveriana and Aconitum napellus.

Acanthamoeba spp. are widely distributed in the environment and cause serious infections in humans. Treatment of Acanthamoeba infections is very challenging and not always effective which requires the development of more efficient drugs against Acanthamoeba spp. The purpose of the present study was to test medicinal plants that may be useful in the treatment of Acanthamoeba spp. Here we evaluated the trophozoital and cysticidal activity of 13 flavonoid glycosides isolated from Delphinium gracile, D. staphisagria, Consolida oliveriana and from Aconitum napellus subsp. Lusitanicum against the amoeba Acanthamoeba castellanii. AlamarBlue Assay Reagent® was used to determine the activity against trophozoites of A. castellanii, and cytotoxic using Vero cells. Cysticidal activity was assessed on treated cysts by light microscopy using a Neubauer chamber to quantify cysts and trophozoites. Flavonoids 1, 2, 3 and 4 showed higher trophozoital activity and selectivity indexes than the reference drug chlorhexidine digluconate. In addition, flavonoid 2 showed 100% cysticidal activity at a concentration of 50 µm, lower than those of the reference drug and flavonoid 3 (100 µm). These results suggest that flavonoids 2 and 3 might be used for the development of novel therapeutic approaches against Acanthamoeba infections after satisfactory in vivo evaluations.

Antineoplastic kinase inhibitors: A new class of potent anti-amoebic compounds.

Entamoeba histolytica is a protozoan parasite which infects approximately 50 million people worldwide, resulting in an estimated 70,000 deaths every year. Since the 1960s E. histolytica infection has been successfully treated with metronidazole. However, drawbacks to metronidazole therapy exist, including adverse effects, a long treatment course, and the need for an additional drug to prevent cyst-mediated transmission. E. histolytica possesses a kinome with approximately 300-400 members, some of which have been previously studied as potential targets for the development of amoebicidal drug candidates. However, while these efforts have uncovered novel potent inhibitors of E. histolytica kinases, none have resulted in approved drugs. In this study we took the alternative approach of testing a set of twelve previously FDA-approved antineoplastic kinase inhibitors against E. histolytica trophozoites in vitro. This resulted in the identification of dasatinib, bosutinib, and ibrutinib as amoebicidal agents at low-micromolar concentrations. Next, we utilized a recently developed computational tool to identify twelve additional drugs with human protein target profiles similar to the three initial hits. Testing of these additional twelve drugs led to the identification of ponatinib, neratinib, and olmutinib were identified as highly potent, with EC50 values in the sub-micromolar range. All of these six drugs were found to kill E. histolytica trophozoites as rapidly as metronidazole. Furthermore, ibrutinib was found to kill the transmissible cyst stage of the model organism E. invadens. Ibrutinib thus possesses both amoebicidal and cysticidal properties, in contrast to all drugs used in the current therapeutic strategy. These findings together reveal antineoplastic kinase inhibitors as a highly promising class of potent drugs against this widespread and devastating disease.

Trichomonas vaginalis NTPDase inhibited by lycorine modulates the parasite-neutrophil interaction.

Lycorine is an Amaryllidaceae alkaloid that presents anti-Trichomonas vaginalis activity. T. vaginalis causes trichomoniasis, the most common non-viral sexually transmitted infection. The modulation of T. vaginalis purinergic signaling through the ectonucleotidases, nucleoside triphosphate diphosphohydrolase (NTPDase), and ecto-5'-nucleotidase represents new targets for combating the parasite. With this knowledge, the aim of this study was to investigate whether NTPDase and ecto-5'-nucleotidase inhibition by lycorine could lead to extracellular ATP accumulation. Moreover, the lycorine effect on the reactive oxygen species (ROS) production by neutrophils and parasites was evaluated as well as the alkaloid toxicity. The metabolism of purines was assessed by HPLC. ROS production was measured by flow cytometry. Cytotoxicity against epithelial vaginal cells and fibroblasts was tested, as well as the hemolytic effect of lycorine and its in vivo toxicity in Galleria mellonella larvae. Our findings showed that lycorine caused ATP accumulation due to NTPDase inhibition. The alkaloid did not affect the ROS production by T. vaginalis; however, it increased ROS levels in neutrophils incubated with lycorine-treated trophozoites. Lycorine was cytotoxic against vaginal epithelial cells and fibroblasts; conversely, it was not hemolytic neither exhibited toxicity against the in vivo model of G. mellonella larvae. Overall, besides having anti-T. vaginalis activity, lycorine modulates ectonucleotidases and stimulates neutrophils to secrete ROS. This mechanism of action exerted by the alkaloid could enhance the susceptibility of T. vaginalis to host immune cell, contributing to protozoan clearance.

Vitamin supplementation increases the virulence of Entamoeba histolytica grown axenically.

As a consequence of axenic growth and the elimination of accompanying bacterial flora, Entamoeba histolytica virulence decreases rapidly, and pathogenicity is lost. This paper evaluated the impact of vitamin supplementation on the pathogenicity of E. histolytica. Growth of E. histolytica trophozoites, cultured axenically in PEHPS (a Spanish acronym for the main ingredients - casein peptone, liver, pancreas extract and bovine serum) medium, with or without vitamins, exhibited a similar growth rate. However, the vitamin-enriched PEHPS preparations expressed 2.65 times more haemolytic activity (at 60 min: 98 vs 48%, P < 0.05), 2.5 times more phospholipase A2 activity at 150 min of incubation and generated more hepatic abscesses (88 vs 60%, P = 0.05) than the preparations without vitamins. The haemolytic and phospholipase A2 activity for the PEHPS - V preparations were restored following vitamin supplementation with A and D. These data highlight, for the first time, that vitamins and specifically vitamin A and D were essential for the recovery of amoebic virulence, lost through axenic growth.

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.

Spirocyclic chromanes exhibit antiplasmodial activities and inhibit all intraerythrocytic life cycle stages.

We screened a collection of synthetic compounds consisting of natural-product-like substructural motifs to identify a spirocyclic chromane as a novel antiplasmodial pharmacophore using an unbiased cell-based assay. The most active spirocyclic compound UCF 201 exhibits a 50% effective concentration (EC50) of 350 nM against the chloroquine-resistant Dd2 strain and a selectivity over 50 using human liver HepG2 cells. Our analyses of physicochemical properties of UCF 201 showed that it is in compliance with Lipinski's parameters and has an acceptable physicochemical profile. We have performed a limited structure-activity-relationship study with commercially available chromanes preserving the spirocyclic motif. Our evaluation of stage specificities of UCF 201 indicated that the compound is early-acting in blocking parasite development at ring, trophozoite and schizont stages of development as well as merozoite invasion. SPC is an attractive lead candidate scaffold because of its ability to act on all stages of parasite's aexual life cycle unlike current antimalarials.

The redox-active drug metronidazole and thiol-depleting garlic compounds act synergistically in the protist parasite Spironucleus vortens.

Spironucleus vortens is a protozoan parasite associated with significant mortalities in the freshwater angelfish, Pterophyllum scalare. Control of this parasite is especially problematic due to restrictions on the use of the drug of choice, metronidazole (MTZ), on fish farms. Use of garlic (Allium sativum) is undergoing a renaissance following experimental validations of its antimicrobial efficiency. Ajoene ((E,Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide), is a stable transformation product of allicin, the primary biologically active component of garlic. In the current study, an ajoene oil crude extract had a minimum inhibitory concentration (MIC) of 40µg/ml against S. vortens. GC-MS and NMR spectroscopy revealed this ajoene extract contained a mixture of the (E) and (Z)-ajoene isomers along with diallyl disulphide (DADS) and diallyl trisulphide (DATS). The only component of the ajoene crude oil found to substantially inhibit S. vortens growth by optical density monitoring (Bioscreen C Reader) was (Z)-ajoene (MIC 16µg/ml). Ajoene oil acted in synergy with MTZ in vitro, reducing the individual MIC of this drug (4µg/ml) by 16-fold, and that of ajoene oil by 200-fold with a fractional inhibitory concentration (FIC) index of 0.263. This synergistic interaction was confirmed in vivo. S. vortens-infected Pterophyllum scalare angelfish dosed orally with 0.5% (v/w) MTZ combined with 0.05% (v/w) ajoene displayed a significant reduction in faecal trophozoite count, whilst those fed on 0.5% MTZ flakes (half the recommended oral dose) alone did not. This study demonstrates for the first time the synergistic interaction between the synthetic drug MTZ and natural ajoene oil both in vitro and in vivo. Future work should evaluate the potential synergy of ajoene and MTZ against MTZ-resistant bacteria and protists.

Kaempferol inhibits Entamoeba histolytica growth by altering cytoskeletal functions.

The flavonoid kaempferol obtained from Helianthemum glomeratum, an endemic Mexican medicinal herb used to treat gastrointestinal disorders, has been shown to inhibit growth of Entamoeba histolytica trophozoites in vitro; however, the mechanisms associated with this activity have not been documented. Several works reported that kaempferol affects cytoskeleton in mammalian cells. In order to gain insights into the action mechanisms involved in the anti-amoebic effect of kaempferol, here we evaluated the effect of this compound on the pathogenic events driven by the cytoskeleton during E. histolytica infection. We also carried out a two dimensional gel-based proteomic analysis to evidence modulated proteins that could explain the phenotypical changes observed in trophozoites. Our results showed that kaempferol produces a dose-dependent effect on trophozoites growth and viability with optimal concentration being 27.7 µM. Kaempferol also decreased adhesion, it increased migration and phagocytic activity, but it did not affect erythrocyte binding nor cytolytic capacity of E. histolytica. Congruently, proteomic analysis revealed that the cytoskeleton proteins actin, myosin II heavy chain and cortexillin II were up-regulated in response to kaempferol treatment. In conclusion, kaempferol anti-amoebic effects were associated with deregulation of proteins related with cytoskeleton, which altered invasion mechanisms.

Sonoran propolis and some of its chemical constituents inhibit in vitro growth of Giardia lamblia trophozoites.

Propolis is a cereus resin with a complex chemical composition that possesses a wide range of biological activities. The aim of this study was to evaluate the in vitro anti-Giardia lamblia activity of Sonoran propolis collected from three different areas of Sonoran Desert in northwestern Mexico (Caborca, Pueblo de Alamos, and Ures) and some of its chemical constituents. Additionally, we also analyzed the seasonal effect on the anti-G. lamblia activity of propolis. G. lamblia trophozoite cultures were treated with different concentrations of Sonoran propolis or chemical compounds during 48 h cell proliferation and cell viability were determined. Ures propolis showed the highest inhibitory activity against G. lamblia (IC50 63.8 ± 7.1 µg/mL) in a dose-dependent manner (Ures > Pueblo de Alamos > Caborca). Season had a significant effect on the in vitro anti-G. lamblia activity of Ures propolis. Summer propolis showed the highest inhibitory effect on the G. lamblia trophozoite growth (IC50 23.8 ± 2.3 µg/mL), followed by propolis collected during winter (IC50 59.2 ± 34.7 µg/mL), spring (IC50 102.5 ± 15.3 µg/mL), and autumn (IC50 125.0 ± 3.1 µg/mL). Caffeic acid phenethyl ester, an Ures propolis exclusive constituent, had the highest growth-inhibitory activity towards G. lamblia [IC50 63.1 ± 0.9 µg/mL (222.1 ± 3.2 µM)]. To our knowledge, this is the first study showing that caffeic acid phenethyl ester possesses antiparasitic activity against G. lamblia. Naringenin [IC50 125.7 ± 20.7 µg/mL (461.8 ± 76.3 µM)], hesperetin [IC50 149.6 ± 24.8 µg/mL (494.9 ± 82.2 µM)], and pinocembrin [IC50 174.4 ± 26.0 µg/mL (680.6 ± 101.7 µM)] showed weak anti-G. lamblia activity. On the other hand, chrysin and rutin did not show significant antiparasitic activity. In conclusion, our results suggest that Sonoran propolis and some of its chemical constituents had inhibitory effects on the in vitro growth of G. lamblia trophozoites.

Bioassay guided isolation and identification of anti-Acanthamoeba compounds from Tunisian olive leaf extracts.

Pathogenic Acanthamoeba strains are causative agents of Granulomatous Amoebic Encephalitis (GAE) and Acanthamoeba keratitis (AK) worldwide. The existence of the cyst stage complicates Acanthamoeba therapy as it is highly resistant to antibiotics and physical agents. The aim of this study was to investigate the activity of Limouni olive leaf cultivar against the trophozoite stage of Acanthamoeba. The ethyl acetate and methanol extracts of this variety were tested against Acanthamoeba castellanii Neff. The ethyl acetate extract of olive leaf was the most active showing an IC50 of 5.11±0.71µg/ml of dry extract. Bio-guided fractionation of this extract was conducted and led to the identification of three active compounds namely oleanolic and maslinic acids and oleuropein which could be used for the development of novel therapeutic approaches against Acanthamoeba infections.

Amoebicidal activity of phytosynthesized silver nanoparticles and their in vitro cytotoxicity to human cells.

Acanthamoeba causes infections in humans and other animals and it is important to develop treatment therapies. Jatropha curcas, Jatropha gossypifolia and Euphorbia milii plant extracts synthesized stable silver nanoparticles (AgNPs) that were relatively stable. Amoebicidal activity of J. gossypifolia, J. curcas and E. milii leaf extracts showed little effect on viability of Acanthamoeba castellanii trophozoites. Plant-synthesized AgNPs showed higher amoebicidal activity. AgNPs synthesized by J. gossypifolia extract were able to kill 74-27% of the trophozoites at concentrations of 25-1.56 µg mL(-1) . AgNPs were nontoxic at minimum inhibitory concentration with peripheral blood mononuclear cells. These results suggest biologically synthesized nanoparticles as an alternative candidate for treatment of Acanthamoeba infections.

Giardia intestinalis: effects of Pulsatilla chinensis extracts on trophozoites.

Pulsatilla chinensis is a medicinal root plant that has been used to treat a wide range of disease conditions. Our study determined the antiprotozoal activity of various P. chinensis extracts and fractions against Giardia intestinalis including their effects on parasite growth, cell viability, adherence, and morphology. Ethyl acetate extracts (IC50 = 257.081 µg/ml) were the most active to inhibit the growth of G. intestinalis followed by aqueous extract (PWE), saponins, and n-butanol extract. The PWE and ethyl acetate extract inhibited G. intestinalis trophozoites adherence after 3 h of incubation and killed almost 50 % of the parasite population in a time-dependent manner. Changes in morphology, presence of precipitates in the cytoplasm, dissolved cytoplasm with large vacuole, break of flagella and ventral disk, membrane blebs, and intracellular and nuclear clearance of the treated trophozoites were observed by scanning and transmission electron microscopy. We demonstrated that P. chinensis induced these changes in G. intestinalis morphology and consequently has potential therapeutic use against giardiasis.

In vitro amoebicidal activity of Origanum syriacum and Origanum laevigatum on Acanthamoeba castellanii cysts and trophozoites.

In some patients, complete treatment of amoebic keratitis is difficult because of the resistance of cysts to therapeutic agents. The aim of this study was to evaluate the in vitro amoebicidal activity of methanolic extracts of Origanum syriacum and Origanum laevigatum. In the presence of methanolic extracts (ranging from 1.0 to 32.0mg/ml), numbers of the viable Acanthamoeba castellanii trophozoites and cysts were decreased. Both extracts showed a time and dose dependent amoebicidal action on the trophozoites and cysts. Of the extracts tested, O. syriacum showed the stronger amoebicidal effect on the trophozoites and cysts. In the presence of 32 mg/ml extract, no viable trophozoites were observed within third hour. The extract was also found effective against the cysts within 24th hour. In the case of O. laevigatum, no viable trophozoites were observed within 72nd hour at the concentrations of 16 and 32 mg/ml. As expected, cysts were found more resistant to the extracts than the trophozoites.

New advances in the in-vitro culture of Dientamoeba fragilis.

SUMMARYDientamoeba fragilis is an intestinal protozoan in humans that is commonly associated with diarrhoea and other gastrointestinal complaints. Studies conducted to investigate the biology of this parasite are limited by methods for in vitro cultivation. The objective of this study was to improve a biphasic culture medium, based on the Loeffler's slope, by further supplementation in order to increase the yield of trophozoites in culture. The current in vitro culture of D. fragilis is a xenic culture with a mix of bacteria. Three different liquid overlays were evaluated including Earle's balanced salt solution (EBSS), PBS and Dulbecco's modified PBS (DPBS), for their ability to support the in vitro growth of D. fragilis trophozoites. Out of these 3 overlays EBSS gave the highest increase in the trophozoite numbers. The effect of supplementation was analysed by supplementing EBSS with ascorbic acid, ferric ammonium citrate, L-cysteine, cholesterol and alpha-lipoic acid and quantification of in vitro growth by cell counts. A new liquid overlay is here described based upon EBSS supplemented with cholesterol and ferric ammonium citrate that, in conjunction with the Loeffler's slope, supports the growth of D. fragilis trophozoites in vitro. This modified overlay supported a 2-fold increase in the numbers of trophozoite in culture from all 4 D. fragilis isolates tested, when compared to a PBS overlay. These advances enable the harvest of a larger number of trophozoites needed for further studies on this parasite.

Differential effectiveness of berry polyphenols as anti-giardial agents.

Following previous work on the anti-giardial effect of blueberry polyphenols, a range of polyphenol-rich extracts from berries and other fruits was screened for their ability to kill Giardia duodenalis, an intestinal parasite of humans. Polyphenol-rich extracts were prepared from berries using solid-phase extraction and applied to trophozoites of Giardia duodenalis grown in vitro. All berry extracts caused inhibition at 166 µg gallic acid equivalents (GAE)/ml phenol content but extracts from strawberry, arctic bramble, blackberry and cloudberry were as effective as the currently used drug, metronidazole, causing complete trophozoite mortality in vitro. Cloudberry extracts were found to be the most effective causing effectively complete trophozoite mortality at 66 µg GAE/ml. The polyphenol composition of the more effective berry extracts suggested that the presence of ellagitannins could be an important factor. However, the potency of cloudberry could be related to high ellagitannin content but also to the presence of substantial amounts of unconjugated p-coumaric acid and benzoic acid. These in vitro effects occur at concentrations easily achievable in the gut after berry ingestion and we discuss the likelihood that berry extracts could be effective anti-giardial agents in vivo.

Comparison of protein-free defined media, and effect of L-cysteine and ascorbic acid supplementation on viability of axenic Entamoeba histolytica.

Entamoeba histolytica is the etiologic agent for amoebiasis. The excretory-secretory (ES) products of the trophozoites contain virulence factors and antigens useful for diagnostic applications. Contaminants from serum supplements and dead trophozoites impede analysis of ES. Therefore, a protein-free medium that can sustain maximum viability of E. histolytica trophozoites for the longest time duration will enable collection of contaminant-free and higher yield of ES products. In the present study, we compared the efficacy of four types of media in maintaining ≥ 95% trophozoite viability namely Roswell Memorial Park Institute (RPMI-1640), Dulbecco's Modified Eagle Medium (DMEM), phosphate-buffered saline for amoeba (PBS-A), and Hank's balanced salt solution (HBSS). Concurrently, the effect of adding L: -cysteine and ascorbic acid (C&A) to each medium on the parasite viability was also compared. DMEM and RPMI 1640 showed higher viabilities as compared to PBS-A and HBSS. Only RPMI 1640 showed no statistical difference with the control medium for the first 4 h, however the ≥ 95% viability was only maintained for the first 2 h. The other protein-free media showed differences from the serum- and vitamin-free TYI-S-33 control media even after 1 h of incubation. When supplemented with C&A, all media were found to sustain higher trophozoite viabilities than those without the supplements. HBSS-C&A, DMEM-C&A, and RPMI 1640-C&A demonstrated no difference (P>0.05) in parasite viabilities when compared with the control medium throughout the 8-h incubation period. DMEM-C&A showed an eightfold increment in time duration of sustaining ≥ 95% parasite viability, i.e. 8 h, as compared to DMEM alone. Both RPMI 1640-C&A and HBSS-C&A revealed fourfold and threefold increments (i.e., 8 and 6 h, respectively), whereas PBS-A-C&A showed only one fold improvement (i.e., 2 h) as compared to the respective media without C&A. Thus, C&A-supplemented DMEM or RPMI are recommended for collection of ES products.

Effect of phosphatidylcholine-cholesterol liposomes on Entamoeba histolytica virulence.

Trophozoites of Entamoeba histolytica HM-1:IMSS become less virulent after long-term maintenance in axenic cultures. The factors responsible for the loss of virulence during in vitro cultivation remain unclear. However, it is known that in vitro cultivation of amoeba in culture medium supplemented with cholesterol restores their virulence. In this study, we analyzed the effect of adding phosphatidylcholine-cholesterol (PC-Chol) liposomes to the culture medium and evaluated the effect of this lipid on various biochemical and biological functions of E. histolytica HM-1:IMSS in terms of its virulence. The addition of PC-Chol liposomes to the culture medium maintained the virulence of these parasites against hamster liver at the same level as the original virulent E. histolytica strain, even though these amoebae were maintained without passage through hamster liver for 18 months. The trophozoites also showed increased endocytosis, erythrophagocytosis, and carbohydrate residue expression on the amoebic surface. Protease activities were also modified by the presence of cholesterol in the culture medium. These findings indicate the capacity of cholesterol to preserve amoeba virulence and provide an alternative method for the maintenance of virulent E. histolytica trophozoites without the need for in vivo procedures.

Infectivity of Giardia duodenalis Assemblages A and E for the gerbil and axenisation of duodenal trophozoites.

Establishing in vitro cultures of Giardia duodenalis trophozoites from faecal cysts remains very difficult due to poor excystation and bacterial contamination. This study investigated an alternative approach starting from duodenal trophozoites of gerbils that were artificially infected with field isolates from humans (Assemblages A and B) and cattle (Assemblage E and mixed E/A). Gerbil infection was successful for Assemblages A (1/1) and B (1/3) from humans, and for E (1/2) and mixed E/A (6/6) from cattle. Despite the fact that some isolates subsequently failed or were difficult to establish in vitro, several Assemblage A and Assemblage E in vitro trophozoite cultures were successful, however, subsequent cloning required adaptation of the standard TYI-S-33 medium whereby different medium supplements were required for promoting growth. Excess of l-cysteine (2mg/ml) and ascorbic acid (0.2mg/ml) supported cloning of Assemblage A, while l-glutathione (7.8 mg/ml) was required for Assemblage E. This is a first description of in vitro axenisation of Assemblage E trophozoites from cattle.

Induction of cell death on Plasmodium falciparum asexual blood stages by Solanum nudum steroids.

Solanum nudum Dunal (Solanaceae) is a plant used in traditional medicine in Colombian Pacific Coast, from which five steroids denominated SNs have been isolated. The SNs compounds have antiplasmodial activity against asexual blood stages of Plasmodium falciparum strain 7G8 with an IC(50) between 20-87microM. However, their mode of action is unknown. Steroids regulate important cellular functions including cell growth, differentiation and death. Thus, the aim of this work was to determine the effects of S. nudum compounds on P. falciparum asexual blood stages and their association with cell death. We found that trophozoite and schizont stages were the most sensitive to SNs. By Giemsa-stained smears, induction of crisis forms was observed. Transmission electron microscopy of treated parasites showed morphological abnormalities such as a cytoplasm rich in vesicles and myelinic figures. The Mitochondria presented no morphological alterations and the nuclei showed no abnormal chromatin condensation. By the use of S. nudum compounds, cell death in P. falciparum was evident by a decrease in mitochondrial membrane potential, DNA fragmentation and cytoplasmic acidification. The asexual blood stages of P. falciparum showed some apoptotic-like and autophagic-like cell death characteristics induced by SNs treatment.

Effect of Mexican medicinal plant used to treat trichomoniasis on Trichomonas vaginalis trophozoites.

Crude methanolic extracts from 22 Mexican medicinal plants were screened for antitrichomonal activity against Trichomonas vaginalis, which is the etiological agent of trichomoniasis. Among the plants tested Carica papaya and Cocos nucifera showed the best antitrichomonal activity with IC(50) values of 5.6 and 5.8 microg/ml, respectively. The extracts of Bocconia frutescens, Geranium mexicanum, and Lygodium venustum showed moderate activity with IC(50) values ranging from 30.9 to 60.9 microg/ml. All the other plant extracts were inactive (IC(50)>100 microg/ml). All extracts tested were less active than metronidazole (IC(50) 0.037 microg/ml), an antiprotozoal drug used as positive control. The results of the antiprotozoal screening support the popular uses of five of the plants tested for the treatment of some urogenital tract disorders in Mexican traditional medicine. However, seeds of Carica papaya and aerial parts of Bocconia frutescens should be used in herbal medicine with care to avoid toxicity.