Giardia Duodenalis Trophozoites Research Articles

In vitro Culture and Multilocus Genotyping of Giardia duodenalis Trophozoites Obtained from Human Fecal Samples in Southwest Iran.

The enteric protozoa, Giardia duodenalis (G. duodenalis), consists of eight distinct assemblages (A-H) with identical morphological characteristics and a direct life cycle. Successful axenic cultivation of this parasite is an important preliminary step for biological, drug resistance and phylogenetic studies. Moreover, G. duodenalis exhibits great genetic and biotypic diversity. The current study aimed to evaluate In vitro culture and multilocus genotyping of G. duodenalis trophozoites obtained from human fecal samples in southwest Iran. Thirty human fecal specimens containing G. duodenalis cysts were collected from Ahvaz city (southwest of Iran). The purification of cysts was carried out by the sucrose flotation technique. The cysts were inoculated in a modified TYI-S-33 medium and was daily monitored for the development and viability of trophozoites. After extracting DNA, gdh, bg and tpi genes were evaluated using molecular techniques (the semi-nested PCR for gdh gene and the nested PCR for tpi and bg genes). Eventually, the amplified fragments were sequenced and then, the phylogenetic tree was drawn. Of 30, the trophozoites were encysted from five samples. All three genes were detected in two cases of five samples using molecular techniques. The multilocus phylogenetic analysis demonstrated that all the two samples belonged to assemblage A and sub-assemblage AІІ. Our findings indicated the presence of different numbers of trophozoites with variable development and survival rates in modified TYI-S-33 medium. Furthermore, the multilocus genotyping showed that these trophozoites belonged to assemblage A and sub-assemblage AІІ.

Metronidazole Refractory Giardiasis Complicating the Management of Rhabdomyosarcoma in a Child

Giardiasis caused by Giardia duodenalis is one of the leading causes of gastroenteritis, especially in developing countries. The scenario may be further complicated by emerging metronidazole refractory cases worldwide. We present a case of a 2-year-old girl on chemotherapy for metastatic para meningeal rhabdomyosarcoma. She had a 15 day history of persistent diarrhea of foul-smelling loose stools, without fever. Light microscopy of stool wet mounts revealed cysts and trophozoites of Giardia duodenalis. The patient was managed with nitazoxanide after metronidazole proved ineffective clinically. This case highlights the importance of timely diagnosis and management of infectious diseases and rising antimicrobial resistance among parasites.

A monoclonal antibody against a Leishmania mexicana COX-like enzymatic activity also recognizes similar proteins in different protozoa of clinical importance.

In Leishmania mexicana, the protease gp63 has been documented as the protein responsible for cyclooxygenase (COX) activity. The present work aimed to obtain a monoclonal antibody capable of recognizing this protein without blocking the COX-like enzymatic activity. The antibody produced by the selected hybridoma was named D12 mAb. The antigen recognized by the D12 mAb was characterized by the determination of COX activity associated with immune complexes in the presence of exogenous arachidonic acid (AA) using the commercial Activity Assay Abcam kit. LSM-SMS analysis validated the identity of the antigen associated with the D12 mAb as the L. mexicana protease gp63. Confocal microscopy assays with the D12 mAb detected, by cross-recognition, similar proteins in other protozoan parasites. COX-like molecules are located in vesicular structures, homogeneously distributed throughout the cytoplasm in amastigotes (intracellular infectious phase) and promastigotes of L. mexicana, and trophozoites of Entamoeba histolytica, Acanthamoeba castellanii, and Naegleria fowleri. However, in Giardia duodenalis trophozoites, the distribution of the COX-like molecule was also in perinuclear areas. In comparison, in Trypanosoma cruzi trypomastigotes, the distribution was mainly observed in the plasma membrane. Structural analyses of COX-2-like antigens revealed continuous and discontinuous epitopes for B cells, which could be relevant in the cross-reaction of D12 mAb with the analyzed parasites. These results indicate that the D12 mAb against the L. mexicana gp63 also recognizes a COX-like molecule in several protozoan parasites, suggesting that this D12 mAb could potentially be used in combined therapies against infectious diseases.

Giardia duodenalis trophozoites triggered bovine neutrophil extracellular traps formation dependent on P2X1 receptor and PAD4 in vitro

Giardia duodenalis is an important intestinal protozoan parasite, infections of which are frequently seen in cattle and cause intermittent diarrhea and weight loss in young animals around the world. The release of neutrophil extracellular traps (NETs) is an effector mechanism of neutrophils to fight against invading pathogens including parasites. In this present study, we aimed to investigate the effect of Giardia duodenalis trophozoites on bovine NETs formation, and to further examine its basic characteristics and molecular mechanisms. Scanning electron microscopy analyses displayed that Giardia duodenalis trophozoites exposure triggered NET-like filamentary structures released by bovine polymorphonuclear leukocytes (PMNs), and many trophozoites were entrapped within these structures. Immunofluorescence analyses illustrated that these structures were mainly composed of DNA, histones, Myeloperoxidase (MPO) and neutrophil elastase (NE), which confirmed the classical characteristics of NETs. NETs quantification showed that Giardia duodenalis trophozoites significantly increased NETs formation, and it is in a dose-dependent manner from 4:1–1:2 ratio of PMN: trophozoites. Furthermore, pharmacological inhibitory experiment indicated that P2X1 receptor and PAD4 were essential for Giardia duodenalis trophozoites-triggered NETs formation. Additionally, LC3B-based immunostaining analyses revealed that autophagy and NETs formation occurred simultaneously in Giardia duodenalis trophozoites-exposed bovine PMN, imply that autophagy may play a key role in Giardia duodenalis trophozoites-triggered bovine NETs. In summary, these findings suggest that NETs formation might have a crucial role in innate host defense against Giardia duodenalis trophozoites. Hence, we call for future molecular investigations not only on Giardia duodenalis trophozoites-triggered NETs but also on its potential role in giardiasis-related pathology in vivo.

Antigiardial Activity of Foeniculum vulgare Hexane Extract and Some of Its Constituents.

Foeniculum vulgare is used for the treatment of diarrhea in Mexican traditional medicine. Hexane extract showed 94 % inhibition of Giardia duodenalis trophozoites at 300 μg/mL. Therefore, 20 constituents of hexane extract were evaluated to determine their antigiardial activity. Interestingly, six compounds showed good activity toward the parasite. These compounds were (1R,4S) (+)-Camphene (61%), (R)(−)-Carvone (66%), estragole (49%), p-anisaldehyde (67%), 1,3-benzenediol (56%), and trans, trans-2,4-undecadienal (97%). The aldehyde trans, trans-2,4-undecadienal was the most active compound with an IC50 value of 72.11 µg/mL against G. duodenalis trophozoites. This aldehyde was less toxic (IC50 588.8 µg/mL) than positive control metronidazole (IC50 83.5 µg/mL) against Vero cells. The above results could support the use of F. vulgare in Mexican traditional medicine.

Molecular Identification of Giardia Duodenalis Isolates from Children Stool in Diyala Province, Iraq

One of the most prevalent human intestine protozoan parasites in the world, Giardia duodenalis is indigenous to every continent and infects a broad variety of animal hosts. The goal of the current study was to determine the prevalence of infection among Giardia duodenalis isolates from regional hospitals and private clinics in the Iraqi province of Diyala that would be the subject of additional genetic analysis. From the beginning of October 2021 to the end of January 2022, 100 children's stools were collected from hospitals and health centers in Diyala, Iraq. Additionally, Giardia duodenalis cysts and trophozoites were examined under the microscope, and DNA was extracted using Quick-DNA Fecal/Soil Microbe Kits. One hundred of the stools taken from youngsters show symptoms of diarrhoea, nausea, and abdominal pains Based on microscopic examination and PCR analysis, a 7 percent infection rate was discovered. In addition, genotyping was carried out utilizing G. duodenalis Tpi sequence analysis. The highest infection rate was 10 % in up 4-5 year category and the lowest infection rate 4.65% recorded in up one year category. While, the infection rate was highest in male samples 8.16% than female samples 5.88%. Regarding the giardiasis according to the house system, most people who were infected were living in the city centre at ratio 9.25%, followed by 4.34 % in persons living in the country side. On the other hand, the infection rate of Giardia infection was 6.89%,4.16% and 8.51% to the tap water, Reverse Osmosis(RO) water and filter water respectively. The findings of this study emphasize that area of study was G. duodenalis infection rate with source of infection route and water basis in children in this province. The genetic analysis of the region Beta-giardin and RH11 and TPIA in this study showed that this diagnosis of Giardia duodenalis was made after effective amplification of these regions. Keywords: Molecular, Infection rate, Risk factors, Giardia duodenalis.

Detection of Giardia duodenalis in Cattle in Mosul City, Iraq

The total percentage of infection with Giardia duodenalis in (50) ingesta of small intestine and (50) gallbladders which were collected from cattle with different ages and both sexes from abattoir and some butcher shops in Mosul city were 28% ,12% respectively. Staining with Giemsa technique showed a higher percentage of Giardia infection rates for ingesta , gallbladder fluid , intestinal mucosal scraping and gallbladder mucosal scraping were 22%, 16%, 6% and 10%, respectively. There were no significant differences appeared between male and female cattle. The highest rate of infection with Giardia was 50% in animals less than one year old while the lowest rate was17.64%in 3years and more with no significant differences between those two ages. |There was a significant difference between cattle suffering from diarrhea (60%) than without diarrhea (14.28%). The histopathological technique of the gallbladder sections revealed presence of trophozoites of Giardia duodenalis in the lumen of the gallbladder with chronic inflammatory response.

Ultrastructural and proapoptotic-like effects of kaempferol in Giardia duodenalis trophozoites and bioinformatics prediction of its potential protein target.

BACKGROUND Kaempferol (KPF) is a flavonoid with antiparasitic activity including experimental giardiasis which mechanism of action is unknown.OBJECTIVE To analyse the cytotoxic effects of KPF on Giardia duodenalis trophozoites and to identify a likely parasite target of this compound.METHODS We used inhibitory concentrations of KPF (IC25, IC50 and IC100) and albendazole (ABZ) as reference drug. The ultrastructure of the trophozoites was analysed by transmission electron microscopy (TEM) whilst apoptosis/necrosis, production of reactive oxygen species (ROS) and cell cycle progression were assessed by flow cytometry (FCM) and confocal laser microscopy (CLM). Ligand-protein docking analyses were carried out using KPF structure from a drug library and crystal structure of a G. duodenalis aldose reductase (GdAldRed) homolog.RESULTS KPF provoked appearance of perinuclear and periplasmic spaces devoid of cytosolic content and multilamellar structures. KPF induced proapoptotic death associated with partial arrest in the S phase without ROS production. Bioinformatics approaches predicted that GdAldRed is a viable KPF target (ΔG = -7.09 kCal/mol), exhibiting 92% structural identity and a similar coupling pattern as its human homolog.CONCLUSIONS KPF exerted a proapoptotic effect on G. duodenalis trophozoites involving partial interruption of DNA synthesis without oxidative stress or structure damage to chromatin and cytoskeletal structures. GdAldRed is a likely target underlying its antigiardial activity.

Activity of Thioallyl Compounds From Garlic Against Giardia duodenalis Trophozoites and in Experimental Giardiasis.

Fresh aqueous extracts (AGEs) and several thioallyl compounds (TACs) from garlic have an important antimicrobial activity that likely involves their interaction with exposed thiol groups at single aminoacids or target proteins. Since these groups are present in Giardia duodenalis trophozoites, in this work we evaluated the anti-giardial activity of AGE and several garlic's TACs. In vitro susceptibility assays showed that AGE affected trophozoite viability initially by a mechanism impairing cell integrity and oxidoreductase activities while diesterase activities were abrogated at higher AGE concentrations. The giardicidal activities of seven TACs were related to the molecular descriptor HOMO (Highest Occupied Molecular Orbital) energy and with their capacity to modify the –SH groups exposed in giardial proteins. Interestingly, the activity of several cysteine proteases in trophozoite lysates was inhibited by representative TACs as well as the cytopathic effect of the virulence factor giardipain-1. Of these, allicin showed the highest anti-giardial activity, the lower HOMO value, the highest thiol-modifying activity and the greatest inhibition of cysteine proteases. Allicin had a cytolytic mechanism in trophozoites with subsequent impairment of diesterase and oxidoreductase activities in a similar way to AGE. In addition, by electron microscopy a marked destruction of plasma membrane and endomembranes was observed in allicin-treated trophozoites while cytoskeletal elements were not affected. In further flow cytometry analyses pro-apoptotic effects of allicin concomitant to partial cell cycle arrest at G2 phase with the absence of oxidative stress were observed. In experimental infections of gerbils, the intragastric administration of AGE or allicin decreased parasite numbers and eliminated trophozoites in experimentally infected animals, respectively. These data suggest a potential use of TACs from garlic against G. duodenalis and in the treatment of giardiasis along with their additional benefits in the host's health.

Giardipain-1, a protease secreted by Giardia duodenalis trophozoites, causes junctional, barrier and apoptotic damage in epithelial cell monolayers

The adhesion of Giardia duodenalis trophozoites to intestinal epithelial cells allows the onset and maintenance of giardiasis. During these interactions, epithelial cells can be committed to apoptosis by enzymes secreted by the parasites, including cysteine proteases that are increasingly identified as virulence factors in parasitic protozoa. In this work, a monoclonal antibody (mAb1G3) raised against G. duodenalis surface components was found to react with a 25 kDa protein expressed in the cell surface and flagella of G. duodenalis trophozoites. When trophozoites expressing this protein were cultured with IEC-6 intestinal epithelial cell monolayers, a dynamic release of this protein was observed with mAbIG3. Proteomic analysis identified the protein as a mature cathepsin B-like (gCatB) enzyme, whose proteolytic activity, detected in zymograms, was eliminated by CatB inhibitor E-64. This protein was named giardipain-1 due to its functional papain-like features and was purified by affinity chromatography using mAbIG3. Upon exposure to the purified, mature and secreted forms of giardipain-1, IEC-6 epithelial cell monolayers displayed membrane blebbing and phosphatidylserine exposure on the outer cell surface, indicating an apoptotic process. In Madin Darby Canine Kidney (MDCK) cell monolayers, giardipain-1 leads to the appearance of pore-like regions and of gaps along cell–cell junctions, to decreased transepithelial electrical resistance (TER), caspase-3 activation and poly-ADP-ribose polymerase (PARP) fragmentation. At early times during exposure, giardipain-1 co-localized at cell–cell junctions, associated with occludin and induced the delocalization and degradation of tight junction proteins occludin and claudin-1. The damage caused to epithelial monolayers by giardipain-1 was blocked by pre-incubation with the CatB B Inhibitor E-64. Furthermore, silencing the giardipain-1 gene in trophozoites lowered the proteolytic activity of giardipain-1 and reduced the damage in IEC-6 monolayers. The damage observed appears to be specific to giardipain activity since almost no damage was observed when IEC-6 monolayers were incubated with papain, a non-related cysteine protease. Hence this study suggests that giardipain-1 triggers, in epithelial cells, degradation of cell–cell junctional components and apoptotic damage, supporting the notion of giardiapain-1 as a virulence factor of Giardia.

Giardia duodenalis infection among rural communities in Yemen: A community-based assessment of the prevalence and associated risk factors

To investigate the prevalence and risk factors of Giardia infection among rural communities among rural communities in Yemen. In this cross-sectional study, a total of 605 stool samples were collected and screened for the presence of Giardia duodenalis (G.duodenalis) cysts and/or trophozoites by using three different diagnostic methods: direct smear, formalin-ether sedimentation, and trichrome staining. A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, behavioural and environmental characteristics of the participants. Overall, 28.1% (170/605) of the participants were infected by G.duodenalis. The prevalence was significantly higher among male participants compared to female (P=0.034); however, it was not significant among different age groups (P>0.05). Univariate and multivariate analyses identified four variables as the significant key risk factors of Giardia infection among the sampled communities. These are, in addition to being of the male gender, using unsafe water sources for drinking water, not washing hands after defecation, presence of other family members infected with Giardia, and close contact with domestic animals. The study reveals that Giardia infection is still prevalent among rural communities in Yemen. The provision of clean and safe drinking water, proper sanitation, and health education regarding personal hygiene practices, particularly handwashing, as well as identifying and treating infected family members is imperative and these interventions should be considered in a strategy to control intestinal parasites among these communities in order to curtail the transmission and morbidity caused by G.duodenalis.

Immune-Molecular Identification of Giardia Intestinalis in Diarrhoeal Children : Comparison of Three Diagnostic Methods

Giardiasis is a major health problem in both developed and developing world. A variety of methods for diagnosis of Giardia duodenalis cysts or trophozoites is available but still has certain limitations. 100 sample from diarrhoeal children who attending outpatient clinic in Abu El Rish hospital, .Kasr Al Ainy, Faculty of Medicine, Cairo University, Egypt. Giardiasis was diagnosed by direct wet mount, microscopy after formal- ethyl acetate concentration, Ridascreen ELISA assay and n-PCR targeting beta giardin (bg) gene. Using ELISA as reference standard, the methods' sensitivities, specificities, positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR-) likelihood ratios with 95% confidence interval (95% CI) were analyzed.The diagnostic methods were evaluated to determine their impact on the posttest probability using Fagan's nomogram. All the studied methods led to a LR+ higher than 10 indicating ability to ruling in giardiasis. n-PCR recorded LR- equal 0.00 and the probability of giardiasis would be 0% if the test was negative. The methods were also ranked on basis of Multiattribute utility theory and Analytical hierarchy process with ELISA ranked better than n-PCR.

IMMUNE-MOLECULAR IDENTIFICATION OF GIARDIA INTESTINALIS IN DIARRHOEAL CHILDREN: COMPARISON OF THREE DIAGNOSTIC METHODS

Giardiasis is a major health problem in both developed and developing world. A variety of methods for diagnosis of Giardia duodenalis cysts or trophozoites is available but still has certain limitations. 100 sample from diarrhoeal children who attending outpatient clinic in Abu El Rish hospital, .Kasr Al Ainy, Faculty of Medicine, Cairo University, Egypt. Giardiasis was diagnosed by direct wet mount, microscopy after formal- ethyl acetate concentration, Ridascreen ELISA assay and n-PCR targeting beta giardin (bg) gene. Using ELISA as reference standard, the methods' sensitivities, specificities, positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR-) likelihood ratios with 95% confidence interval (95% CI) were analyzed.The diagnostic methods were evaluated to determine their impact on the posttest probability using Fagan's nomogram. All the studied methods led to a LR+ higher than 10 indicating ability to ruling in giardiasis. n-PCR recorded LR- equal 0.00 and the probability of giardiasis would be 0% if the test was negative. The methods were also ranked on basis of Multiattribute utility theory and Analytical hierarchy process with ELISA ranked better than n-PCR.

Characterization of recombinase DMC1B and its functional role as Rad51 in DNA damage repair in Giardia duodenalis trophozoites

Homologous recombination (HR) is a highly conserved pathway for the repair of chromosomes that harbor DNA double-stranded breaks (DSBs). The recombinase RAD51 plays a key role by catalyzing the pairing of homologous DNA molecules and the exchange of information between them. Two putative DMC1 homologs (DMC1A and DMC1B) have been identified in Giardia duodenalis. In terms of sequences, GdDMC1A and GdDMC1B bear all of the characteristic recombinase domains: DNA binding domains (helix-turn-helix motif, loops 1 and 2), an ATPcap and Walker A and B motifs associated with ATP binding and hydrolysis. Because GdDMC1B is expressed at the trophozoite stage and GdDMC1A is expressed in the cyst stage, we cloned the giardial dmc1B gene and expressed and purified its protein to determine its activities, including DNA binding, ATP hydrolysis, and DNA strand exchange. Our results revealed that it possessed these activities, and they were modulated by divalent metal ions in different manners. GdDMC1B expression at the protein and transcript levels, as well as its subcellular localization in trophozoites upon DNA damage, was assessed. We found a significant increase in GdDMC1B transcript and protein levels after ionizing radiation treatment. Additionally, GdDMC1B protein was mostly located in the nucleus of trophozoites after DNA damage. These results indicate that GdDMC1B is the recombinase responsible for DSBs repair in the trophozoite; therefore, a functional Rad51 role is proposed for GdDMC1B.

Strongyloides stercoralis hyperinfection in an immunosuppressed dog from France

Summary Strongyloides stercoralis is a threadworm, whose adult females parasitize the small intestine of mammals causing severe clinical presentations in immunosuppressed animals and puppies. A 10-month-old male Chihuahua dog was referred due to chronic diarrhoeic haematochezia, hematemesis, weight loss, pruritus and cough. During the clinical examination, severe weight loss and alopecia on the abdomen were observed. Stool examinations revealed the presence of alive larvae of S . stercoralis , as well as cysts and trophozoites of Giardia duodenalis . The negativity to S . stercoralis infection was achieved only after administration of ivermectin. Results of this study confirm that routine copromicroscopic methods may fail to diagnose S . stercoralis infection. In addition, although fenbendazole is considered the drug of choice for the treatment of canine strongyloidiasis, ivermectin may be a valid alternative.

Establishment of Canine-Derived Giardia duodenalis Isolates in Culture.

Researchers continue to rely on axenic cultivation of Giardia duodenalis trophozoites in vitro to study the life cycle and host-parasite interactions of G. duodenalis and to develop vaccines and drugs to prevent and treat giardiasis. The majority of in vitro studies of G. duodenalis have used a small subset of isolates, mostly of assemblage A, and these isolates are usually originally isolated from humans. The most commonly used isolate for lab studies is known as WB. Canine giardiasis is a disease of veterinary importance, but it may also be of relevance in zoonotic transmission. Few G. duodenalis isolates from dogs have been adapted to in vitro culture, probably because the methods used are not suitable for the canine-specific genotypes that tend to dominate in most dog populations. In the current study, an experimental approach to cultivating canine-derived isolates of G. duodenalis was attempted by modification of the standard protocol based on physiological differences between the human and canine digestive system. An adapted method is described for improving the rate of in vitro excystation of cysts isolated from dogs by chemically weakening the cyst wall. A new canine-derived assemblage A G. duodenalis isolate was successfully adapted to axenic culture by using this method; the dog apparently had a mixed infection of assemblages A and D, but the assemblage A successfully outcompeted the assemblage D under conditions of in vitro culture. Based on the results, reasons regarding why humans do not seem to be suitable hosts for G. duodenalis in assemblages C and D are discussed.

Giardia duodenalis genetic assemblages and hosts.

Techniques for sub-classifying morphologically identical Giardia duodenalis trophozoites have included comparisons of the electrophoretic mobility of enzymes and of chromosomes, and sequencing of genes encoding β-giardin, triose phosphate isomerase, the small subunit of ribosomal RNA and glutamate dehydrogenase. To date, G. duodenalis organisms have been sub-classified into eight genetic assemblages (designated A–H). Genotyping of G. duodenalis organisms isolated from various hosts has shown that assemblages A and B infect the largest range of host species, and appear to be the main (or possibly only) G. duodenalis assemblages that undeniably infect human subjects. In at least some cases of assemblage A or B infection in wild mammals, there is suggestive evidence that the infection had resulted from environmental contamination by G. duodenalis cysts of human origin.

Double Sonogashira reactions on dihalogenated aminopyridines for the assembly of an array of 7-azaindoles bearing triazole and quinoxaline substituents at C-5: Inhibitory bioactivity against Giardia duodenalis trophozoites

The synthesis of 2,3,5-trisubstituted 7-azaindoles as well as 2,5-disubstituted 7-azaindoles from 3,5-dihalogenated 2-aminopyridines is outlined. Using a double Sonogashira coupling reaction on 2-amino-3,5-diiodopyridine followed by the Cacchi reaction the synthesis of 2,3,5-trisubstituted 7-azaindoles was accomplished. In addition, using two sequential Sonogashira coupling reactions on 2-amino-5-bromo-3-iodopyridine and a potassium t-butoxide mediated ring closure reaction resulted in the assembly of 2,5-disubstituted 7-azaindoles. The 5-alkynyl substituent of the azaindole was easily converted into both quinoxaline and triazole substituents, the latter utilizing an alkyne–azide cycloaddition reaction. Some of these azaindole derivatives showed very promising biological activity against the gastrointestinal protozoal parasite Giardia duodenalis.

Immunolocalization of β- and δ-giardin within the ventral disk in trophozoites of Giardia duodenalis using multiplex laser scanning confocal microscopy

Immunolocalization of β- and δ-giardin in Giardia duodenalis trophozoites revealed that both giardins are strictly associated with the ventral disk (VD). Optical sectioning of the immunolabeled VD, together with quantitative colocalization of δ- and β-giardin immunoreactivity, demonstrated that δ-giardin is primarily localized to the ventral side, and β-giardin is localized to the dorsal side of the VD.

Differential effectiveness of berry polyphenols as anti-giardial agents

SUMMARYFollowing 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.