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Entamoeba Histolytica - A Single Cell Parasite

Updated: Jul 14, 2023

Although i do not consider helping folks with parasites a core part of what i do, or what i specialize in, inevitably in the world of chronic illness, it is something a portion of my clients discover along their path - about 10-15% of clients test positive on stool tests. My own health journey included 11 different parasites across : Single cell parasites, Flat / Tape Worms, and Round Worms. Its familiar territory. The reason for this post and sharing some information on this nasty single celled parasite.... in the last 10 days, i have had 5 clients test positive for Entamoeba Histolytica. Its not uncommon to have multiple stool tests come back positive for parasites every few weeks, but 5, all with the same parasite in about 10 days was a bit much, all courtesy of Vibrant America's Gut Zoomer.


There a few well known national parasite focused practitioners, i am partial to Raphael D'Angelo {Parawellness Research Organization}. In the references, i have listed his document he published on the web for folks to learn about parasites, The Amazing World Of Parasites. He runs his own private testing lab and service in Aurora, Colorado near me, and got into this crazy part of the world by doing stool testing in the Korean War while he was in service as an M.D. years and years ago. Other nationally known parasite experts include the famous Dr. Yu in St. Louis, MO, who has written a couple of books on the subject. There is also Dr. Omar Amin, out of Scottsdale Arizona, and I am sure, more - but these 3 folks have strong national reputations in this area of specialty.


Historically, more on the fringe, we had Hannah Kroeger, who immigrated from Germany, opened a healing clinic in Boulder, CO and eventually would train the more outspoken and famous Houlda Clarke. Hannah founded Kroeger Herbs, and also invented the "Zapper", and, Hannah's Herb Shop still exists to this day in Boulder. Houlda passed away, but not before writing several books, with a strong focus on parasites. Houlda would write that she believed parasites caused cancer because everybody who came to see her who had cancer, also had parasites. I don't necessarily believe fire fighters cause fires:).


Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus Entamoeba.Predominantly infecting humans and other primates causing amoebiasis, E. histolytica is estimated to infect about 35-50 million people worldwide.E. histolytica infection is estimated to kill more than 55,000 people each year.[1]


E. histolytica causes tissue destruction which leads to clinical disease. E. histolytica–induced tissue damage by three main events: direct host cell death, inflammation, and parasite invasion. Once the trophozoites are excysted in the terminal ileum region, they colonize the large bowel, remaining on the surface of the mucus layer and feeding on bacteria and food particles. Occasionally, and in response to unknown stimuli, trophozoites move through the mucus layer where they come in contact with the epithelial cell layer and start the pathological process. Enzymes released allow penetration into intestinal wall and blood vessels, sometimes on to liver and other organs. The trophozoites will then ingest these dead cells. This damage to the epithelial cell layer attracts human immune cells and these in turn can be lysed by the trophozoite, which releases the immune cell's own lytic enzymes into the surrounding tissue, creating a type of chain reaction and leading to tissue destruction. This destruction manifests itself in the form of an 'ulcer' in the tissue, typically described as flask-shaped because of its appearance in transverse section. This tissue destruction can also involve blood vessels leading to bloody diarrhea, amebic dysentery. Occasionally, trophozoites enter the bloodstream where they are transported typically to the liver via the portal system. In the liver a similar pathological sequence ensues, leading to amebic liver abscesses. The trophozoites can also end up in other organs, sometimes via the bloodstream, sometimes via liver abscess rupture or fistulas. Similarly, when the trophozoites travel to the brain, they can cause amoebic brain abscess.[1]


There are a number of effective medications. Several antibiotics are available to treat Entamoeba histolytica. The infected individual will be treated with only one antibiotic if the E. histolytica infection has not made the person sick, and will most likely be prescribed two antibiotics if the person has been feeling sick. Otherwise, below are other options for treatments. [1]


Intestinal infection:

Usually nitroimidazole derivatives (such as metronidazole) are used, because they are highly effective against the trophozoite form of the amoeba. Since they have little effect on amoeba cysts, usually this treatment is followed by an agent (such as paromomycin or diloxanide furoate) that acts on the organism in the lumen. [1] Luminal agents include the following: paromomycin, diiodohydroxyquin, or diloxanide furoate. Dosing for paromomycin is 25 mg/kg to 30 mg/kg per day divided into three doses for 7 days, diiodohydroxyquin is 650 mg orally for 20 days, diloxanide furoate is 500 mg orally three times a day for 10 days.[3]


Liver abscess:

In addition to targeting organisms in solid tissue, primarily with drugs like metronidazole and chloroquine, treatment of liver abscess must include agents that act in the lumen of the intestine (as in the preceding paragraph) to avoid re-invasion. Surgical drainage is usually not necessary, except when rupture is imminent.[1] Metronidazole is the first-line treatment for intestinal amebiasis and amebic liver abscess followed by a luminal agent. Typical dosing for metronidazole is 500 to 750 mg orally 3 times a day for 7 to 10 days in adults. Metronidazole can be safely used in children at a dosing of 35 mg/kg to 50 mg/kg per day divided into three doses. [3]


Poor sanitary conditions are known to increase the risk of contracting amebiasis E. histolytica. In the United States, there is a much higher rate of amebiasis-related mortality in California and Texas (this might be caused by the proximity of those states to E. histolytica-endemic areas, such as Mexico), parts of Latin America, and Asia.[1]


The majority of infections restricted to the lumen of the intestine (“luminal amebiasis”) are asymptomatic. Amebic colitis, or invasive intestinal amebiasis, occurs when the mucosa is invaded. Symptoms include severe dysentery and associated complications. Severe chronic infections may lead to further complications such as peritonitis, perforations, and the formation of amebic granulomas (ameboma). [2]


Amebic liver abscesses are the most common manifestation of extraintestinal amebiasis. Pleuropulmonary abscess, brain abscess, and necrotic lesions on the perianal skin and genitalia have also been observed.[2]


The pathological range includes mucosal inflammation, thickening, ulcers, and necrosis, leading to perforation. Amoebic cysteine proteinases can also contribute to trophozoites' ability to suppress a host’s immune response by being able to cleave and inactivate anaphylatoxins C3a, C5a, IgA, and IgG.[2] Trophozoites can reach other areas of the body, most commonly the liver, which can cause tissue necrosis and abscess formation.[3]


Gastrointestinal: Symptoms typically have a gradual onset, usually over one to three weeks. Common symptoms include diarrhea, bloody stools, weight loss, and abdominal pain.[3]

Liver: Amoebic liver abscess formation is the most common extraintestinal complication. It can be seen in months to years after an individual has had exposure to an endemic area. Symptoms include fever and right upper quadrant pain. Exam findings may include hepatomegaly with hepatic tenderness. Less than 10 percent of patients have jaundice. Common laboratory findings include leukocytosis without eosinophilia, elevated alkaline phosphatase, transaminitis, and elevated erythrocyte sedimentation rate.[3]

Respiratory tract: Pleuropulmonary involvement is a rare complication that causes atelectasis and transudative pleural effusions. In rare cases, an amoebic liver abscess can rupture into the pleural space causing empyema or hepato-bronchial fistula causing fevers, coughing, and respiratory distress.[3]

Cardiac infection: Cardiac infection is an even less common complication than pleuropulmonary disease and occurs with a liver abscess ruptures into the pericardium and presents with symptoms of pericarditis or cardiac tamponade.[3]

Brain infection: Amoebic brain abscesses are very rare with sudden onset symptoms such as headache, vomiting, and mental status changes with rapid progression to death.[3]


In Sum, with detailed references later in the blog article, the potential herbal remedies include:

1. P. anisum (Anise Star, Hawaii pharm}

2. S. cordatum

3. Virgillia oroboides

4. Artemisia sieberi {mugwort, Hawaii Pharm}}

5. Kigelia pinnata {Kigella, Hawaii Pharm}

6. Rubus coriifolius

7. Elaeodendron trichotomum

8. Piper longum {Secrets Of The Tribe Long Pepper}

9. berberin

10. Endemali (herbal product; Kasham.pk}

11. epicatechin {Morinda}

12. kaempferol {Dill}

13. quercetin {same}

14. Camellia sinensis extract {Green Tea Extract}

15. Tamarindus indica {Taramind}


Alternatives to metronidazole include tinidazole, ornidazole, and nitazoaxanide. [3]

In patients with fulminant amoebic colitis or signs of peritonitis, broad-spectrum antibiotics should be started. Surgical intervention may be required with bowel perforation or toxic megacolon. [3]

In uncomplicated cases of amebic liver abscess, it has been shown that there is no benefit to drainage in addition to medical therapy. In situations where there is a lack of clinical response to antibiotic therapy, aspiration or catheter drainage may be necessary. [3]

Pleuropulmonary infections should be treated by aspiration of amebic pleural effusion followed by antimicrobial therapy such as metronidazole with a luminal agent.[3]


The differential diagnosis for E. histolytica intestinal amebiasis includes[3]:

  • Bacterial pathogens: Shigella, Escherichia coli, Salmonella, Campylobacter, and Clostridioides difficile

  • Inflammatory bowel disease

  • Ischemic bowel disease

The differential diagnosis for E. histolytica extraintestinal amebiasis includes[3]:

  • Pyogenic liver abscess

  • Echinococcal disease

  • Malignancy

Complications of E. histolytica infection can involve any of the following:[3]

  • Asymptomatic infection

  • Symptomatic noninvasive infection

  • Acute proctocolitis

  • Fulminant amoebic colitis with perforation

  • Toxic megacolon

  • Chronic non-dysenteric colitis

Extraintestinal conditions resulting from E. histolytica infection include the following:[3]

  • Liver abscess

  • Pleuropulmonary disease

  • Brain abscess

  • Peritonitis

  • Pericarditis

  • Genitourinary disease

  • Perianal cutaneous amebiasis

  • Hepatic vein thrombosis

  • Inferior vena cava thrombosis

  • Ameboma

  • Appendicitis

Abundant information regarding the production of different profiles of cytokines, reactive oxygen species, and nitric oxide produced by inflammatory cells in the liver have shown that this environment is essential in ALA development and the subsequent liver damage. Better knowledge regarding the regulation of these molecules is necessary to have a clearer understanding of the physiopathology of the amebiasis.[4]


Contact-Dependent Cell Killing [5]

Immobilization and killing of immune cells also serves as an ameba’s strategy for evasion from immune surveillance. Amebic trophozoites are able to kill a variety of cells, including neutrophils, T lymphocytes, macrophages, and a variety of tissue culture lines. Adherence of the ameba triggers multiple intracellular events leading to cytotoxic effects to the mammalian cells. Such events include increased intracellular Ca2+, production of ROS, loss of membrane integrity, DNA fragmentation, phosphatidylserine exposure on the cell surface, and caspase-3 activation. It was reported that after host cell killing, E. histolytica preferentially ingest the dead cells. This observation is consistent with the theory that clearance of dead cells and debris by phagocytosis helps to minimize pro-inflammatory responses. A phagocytosis-defective line of E. histolytica apparently showed decreased virulence in vitro and in vivo, suggesting a potential causal link between phagocytosis and virulence. [5]


Huston and colleagues demonstrated that E. histolytica preferentially ingests apoptotic Jurkat cells via recognition of phosphatidylserine and collectins. Amebic calreticulin was found to be the surface receptor for host C1q, and required for phagocytosis of apoptotic cells, but it did not directly mediate cell killing. A few recent studies have started to unveil the detailed molecular mechanisms involved in the ameba phagocytosis. However, the molecular events that take place in host immune cells in particular to suppress (or augment) immune response, together with a missing link between the surface receptor to the internalization machinery, remains totally unknown.


Trogocytosis[5]

Ralston and colleagues have recently reported E. histolytica trophozoites ingested pieces of intact living cells via trogocytosis (“trogo” = nibbling) (153). When trophozoites were incubated with a combination of live and pre-killed host cells (Jurkat T cells), the live cells were ingested by trogocytosis, while the pre-killed host cells were ingested as a whole by canonical phagocytosis. Trogocytosis is an active process that resembles phagocytosis in some ways, i.e., it requires physiological temperature, actin rearrangements, Gal/GalNAc lectin, C2 domain-containing protein kinase, and phosphatidylinositol 3-phosphate kinase signaling, and it is accompanied with a rapid rise in intracellular Ca2+ concentrations. Trogocytosed host cells finally were killed. Trogocytosis of murine IEC was also evident in the in vivo animal model, suggesting that both trogocytosis of live host cells and phagocytosis of dead cells are important for pathogenesis and sustained parasitism of E. histolytica. Since amebic contact can potentially results in multiple outcomes: apoptosis and necrosis, followed by phagocytosis, or trogocytosis, it remains to be elucidated what factors and conditions differentiate these distinct manners of killing and ingestion of target host cells.

IFN-γ[5]

Entamoeba histolytica regulates IFN-γ for survival in the host. In CBA mice, which are susceptible to E. histolytica cecal infection, the amebic infection led to upregulation of Th2 (IL-4, IL-5, and IL-13) and Th17 (IL-17) cytokine responses, while Th1 cytokines, IL-12p35 and IFN-γ, were suppressed (154). This indicates that suppression of INF-γ causes susceptibility of amebiasis. From cohort studies in Bangladesh, susceptible children with malnutrition showed lower IFN-γ levels. Analysis of asymptomatic carriers of E. histolytica showed that carriers had higher levels of IFN-γ, while patients with invasive amebiasis displayed higher levels of IL-4 . The significance of IFN-γ in susceptibility is also implicated for ALA. It is known that more than 80% of all ALA cases occur in adult males, and the male predominance is attributable to testosterone. Lotter and colleagues showed that testosterone inhibits IFN-γ secretion from invariant natural killer T (iNKT) cells stimulated by LPPG, a physiological ligand for CD1d. iNKT cells are a subset of NKT cells that recognize lipid antigens in the context of CD1d and produce IFN-γ and IL-4. E. histolytica LPPG is presented on CD1d to invariant TCR and activates iNKT cells in combination with TLR signaling. αGalCer, a CD1d agonist, stimulates production of both IFN-γ and IL-4, whereas LPPG induces IFN-γ but not IL-4 production. These data suggest that iNKT cells provide a link between innate and adaptive immunity due to their capacity to produce large amounts of IFN-γ and IL-4 that can bias the immune response into either a Th1 or Th2 direction. Production of IFN-γ helps clearance of E. histolytica infection and controls abscess formation, whereas an adequate level of IFN-γ reduces the trophozoite number and pro-inflammatory response at a low level, and may balance for trophozoites to survive.

IL-10 [5]

It is known that anti-inflammatory cytokine, IL-10, plays a critical role to maintain the mucosal barrier. IL-10-deficient mice have compromised and highly permeable mucosal barriers and develop spontaneous intestinal inflammation in response to normal microflora. A murine amebic colitis model demonstrated that IL-10 from hematopoietic cells (CD4+ T cells) acting upon the non-hematopoietic compartment (IEC) is required for innate resistance to parasite invasion. Furthermore, it has been shown that IL-10 enhances MUC2 production, suppresses activation of antigen-presenting cells, induces B cell class-switching to IgA, has anti-apoptotic effects on IECs, reduces pro-inflammatory NFκB signaling in IECs, and promotes induction of CD4+ Treg cells . Interestingly, in asymptomatic carriers, no elevation of IL-10 level was observed. On the other hand, the IL-10 level was increased in dysenteric and ALA patients. These studies indicate that invasion of the colon and liver by E. histolytica elicits an anti-inflammatory immune response and may successfully suppress immune reaction to the amebae. Altogether, the ameba needs to balance IL-10 and inflammatory cytokine levels to establish infection. It was shown that peritoneal monocytes and macrophages exposed to LPPG secreted TNF-α, IL-6, IL-8, IL-12, and IL-10 via TLR2. It has been also shown that high doses of LPPG down-regulated TLR2 gene expression. Thus, LPPG-driven signaling may activate a negative feedback loop that attenuates inflammatory responses. The mechanisms of the suppression of IL-10 production by the ameba remain to be elucidated (see below).


Suppression of NFκB in IECs[5]

Entamoeba histolytica trophozoites secrete materials that induce a protective response in human IECs , the first line of host cells to encounter microbial antigens, via PRRs, including TLRs. Upon binding to their ligand, PRRs trigger activation of a transcription factor NFκB. Gut homeostasis requires continuous activation of NFκB by TLR signaling in response to intestinal bacteria, commensal microbes can also disrupt NFκB signaling to attenuate pro-inflammatory IEC responses. It has been shown that secreted components from E. histolytica trophozoites induce a protective response in human IECs that primed by macrophage secretions through suppression of NFκB via heat shock protein response and increase resistance of IECs to apoptosis. Thus, it appears that E. histolytica elicits a stress response to IECs and promotes a hyporesponsive state toward trophozoites. The amebic factors that induce NFκB suppression have not yet determined. The factors that activate TLR2, i.e., LPPG and Gal/GalNAc lectin, are candidates involved in this pathway.


Prostaglandin PGE2 [5]

Entamoeba histolytica trophozoites produce and secrete prostaglandin 2 (PGE2), which have contact-independent effects on tight junction integrity and ion absorption. Secreted amebic PGE2 binds to prostaglandin E receptor 4 (EP4) on IECs, disrupts tight junctions, and increases luminal Cl− secretion. PGE2 secreted from the amebae elicits inflammatory response in IECs by increasing IL-8 production by IECs. PGE2 is a potent mucin secretagogue that can overcome luminal barrier function by causing hypersecretion and, thus, depletion of the protective mucus barrier. On the contrary, it has been also reported that during invasive amebiasis, local PGE2 has anti-inflammatory effect. In animal model of chronic ALA, hepatic granuloma macrophages do not respond to IFN-γ and LPS and do not produce inflammatory cytokines, show decrease in MHC class II expression, and are unable to kill trophozoites. This suppression is local during chronic ALA and is directly caused by the parasite. A culture supernatant and an unknown soluble protein component of E. histolytica trophozoites decrease class II major histocompatibility complex (MHC II) immune-associated (Ia) antigen expression through a PGE2-dependent manner. Inhibition of macrophage PGE2 synthesis can partially recover MHC II Ia expression and TNF-α expression. However, inhibition of PGE2 synthesis does not recover iNOS expression or amebicidal activity in the deactivated macrophage. A continuous supply of parasite-derived PGE2 likely prevents iNOS expression and full recovery of MHC II and TNF-α, possibly through a concentration-dependent effect of PGE2. In short, ameba-secreted PGE2 represses inflammation in ALA, which is beneficial for survival, whereas it likely enhances destruction of the colon.

Perturbation of the Enteric Microbiota by E. histolytica [5]

It has been reported that E. histolytica infection alters the microbiota composition. E. histolytica-induced dysbiosis was characterized by fewer Bacteroides, Clostridia, Lactobacillus, Campylobacter, and Eubacterium species, and increased Bifidobacterium species. In vitro experiments have shown that E. histolytica preferentially ingest some bacterial species. It is known that amoebapores, a family of the major pore-forming peptides, have differential activity against bacteria and eukaryotes. Furthermore, E. histolytica infection induces production of colonic antimicrobial peptides, while the trophozoites degrade them. A recent study has shown that dendritic cells from the mouse intestine where Clostridia-related bacteria colonized provide IL-17A-dependent protection against amebic colitis. Detailed molecular events remain to be elucidated, however, by examining how alternations of the microbiota modulate host immune responses against amebic intestinal infection. Altogether, microbiota can be modulated by amebic infection, and in turn concentrations of carbohydrates (and other compounds) that affect growth and virulence of the amebae can strongly influence outcome of infection. It remains to be elucidated whether and how the amebae modulate the intestinal microbiota for their survival and parasitism.

Lack of Respiration and Antioxidative Stress Management in E. histolytica [5]

Entamoeba histolytica trophozoites are microaerophilic and consume oxygen. They tolerate low levels of oxygen tension. E. histolytica lacks a conventional respiratory electron transport chain that terminates in the reduction of O2 to H2O. However, it does respire and tolerates up to 5% oxygen in the gas phase. The parasite lacks most of the components of antioxidant defense mechanisms that are widely present in other prokaryotic and eukaryotic organisms, such as catalase, peroxidase, glutathione, and the glutathione-recycling enzymes glutathione peroxidase and glutathione reductase. However, during tissue invasion, trophozoites must fend off reactive oxygen and nitrogen species produced by activated immune cells through the respiratory burst. Thus, trophozoites must use antioxidative stress defense to survive immune surveillance.


Anti-Oxidative Stress Response Contributes to Immune Evasion in E. histolytica [5]

Entamoeba histolytica trophozoites contain high levels of cysteine, instead of glutathione, as the major thiol in the cell. They possess several enzymes to defend from oxidative stress, such as peroxiredoxin (Prx), superoxide dismutase, flavoprotein A, ferredoxin, thioredoxin (Trx), and Trx reductase. The Trx/Trx reductase system is crucial for buffering sensitive proteins under oxidative stress. The amebicidal drugs, metronidazole and auranofin, are known to disrupt Trx. Interestingly, the oxidative stress increases E. histolytica virulence. It has been shown that oxidative stress causes upregulation of a stress-induced adhesion factor and a phospholipid transporting P-type ATPase/flippase. Both genes are involved in adhesion and phagocytosis. Oxidative stress also alters metabolic flux, including glycerol and chitin biosynthesis, potentially triggering encystation . Furthermore, it has been shown that E. histolytica (HM-1:IMSS) responds more strongly to oxidative stress than E. dispar and E. histolytica non-virulent Rahman strain, and surface localization of Prx in HM-1:IMSS is associated with virulence. Altogether, antioxidative defense mechanisms in E. histolytica are associated with pathogenesis. For more details on the antioxidative management in E. histolytica, a recent review should be consulted.


Our understanding of molecular mechanisms of the parasite’s pathogenesis, such as adherence to host cells, induction of apoptosis, degradation of mucin and ECM, tissue invasion, and phago/trogocytosis of host cells, has greatly advanced in recent years. So have mechanisms of immune evasion, such as induction of IL-10 and suppression of INF-γ, degradation of Igs, complement, and pro-inflammatory cytokines. In addition, defense against ROS and NO and evasion from antibody and complement-dependent killing also plays important roles in survival in the host. Furthermore, mutual signaling among the three domains in the complex network of the parasite, the human, and the microbiota with polymorphic genetic backgrounds affect outcome of amebic infection. Further research is needed to elucidate the molecular basis of the complex interaction in the intestinal ecosystem.


In conclusion, this review has discussed studies regarding the E. histolytica biological membranes, which have already been used as a compound or drug target. In future investigations, it might be possible to explore the potential of some discussed membrane and cytosolic proteins as potential drug targets to eliminate this protozoan parasite. Such potential proteins include thioredoxin reductase, cysteine protease, protein phosphatase, alcohol dehydrogenase, triosephosphate isomerase, GTPases, KERP1, the Nickman Pick Type (NPC), and the Interferon-gamma (IFN-γ) receptor. Targeting these proteins may help combat the E. histolytica as they are involved in its pathogenicity. [6]


Plants are a popular choice in developing countries as they can be considered safe and available at a low cost. The study conducted by Mehdi et al. (2019). had shown experiments using Tamarindus indica. The T. indica extract in ethanolic and aqueous form was used against infected rats with E. histolytica. The T. indica contains many functional compounds such as flavonoids, alkaloids, tannins, phenols, and many more, making it suitable to kill E. histolytica. The alkaloids present in the plant extract had broken down the cell membrane of the E. histolytica, which causes the cell contents, such as the proteins and fat, to excrete. Besides, it also interferes with the DNA of E. histolytica. Both effects of the alkaloids result in the death of the E. histolytica. [6]


Furthermore, tannins, another compound present in T. indica extract, inhibit the transport of proteins and enzymes on the cell membranes. The enzymes’ inhibition mechanisms are through the collaboration of tannins and the phenols, which results in protein precipitation through the formation of hydrogen bonds between hydroxyl phenols, nitrogen compounds, and proteins. The results showed the reduced number of E. histolytica in vivo when the dose of 500 mg/kg of the extract was used during the treatment of the rats. Apart from that, the extract also helps to repair the intestine tissue. [6]


This event can be seen from the histopathological section of the colon of the rats, where a moderate increase in the number of goblet cells and thickening of the mucosa of the colon when administered with T. indica extracts occur . Increased goblet cells indicated that the immunity increased in the mucosa of the colon as well as the production of anti-microbial antibodies. Both events showed that this extract is a good indicator for curing patients with E. histolytica infection. [6]


Another natural product used against E. histolytica is a Camellia sinensis extract. A study conducted by Shaker et al. (2018). showed that C. sinensis extract is suitable for targeting the E. histolytica. It contains many beneficial compounds such as alkaloids, phenols, tannins, flavonoids, glycosides, saponins, and resins that kill E. histolytica. Both natural products are effective against E. histolytica. However, the specific biological membranes involved are not reported, which requires a deeper understanding of the mechanism of action. [6]


Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance. [7]


This parallel, randomized, double blind clinical trial was designed to compare allopathic drugs MDF (a combination of metronidazole + diloxanide furoate) with Endemali (herbal product) for therapeutic cure rate and side effects in order to find out the most suitable drug for this killer disease. Methodology: This double blind randomized clinical trial was conducted in 2 areas of Karachi, Pakistan after approval from ethical committee of Hamdard University. All those confirmed for E. histolytica were included in the study. 171 patients selected for study randomly allocated to two arms of 86 and 85 for allopathic and herbal treatment respectively. However, 78 in allopathic and 75 in herbal group completed the study. Main outcome variable was treatment success or failure. Secondary outcome measures included side effects, and association with age and sex. Results: No significant difference was observed in the socioeconomic and demographic variables at the baseline. No significant difference was found between the cure rate of MDF and Endemali; hence both drugs were equally effective in treating amoebiasis. Significant differences were reported for the side effects observed among the 2 groups and the price. The failure rate for the two drugs was 28.7%. Conclusion: It is concluded that both Endemali and MDF are equally effective in treating amoebiasis. However, Endemali has fewer side effects than MDF. New drugs need to be researched for the treatment of Entamoeba histolytica because of high failure rate of the two drugs against this killer organism. [8]


Amoebiasis has emerged as a major health problem worldwide. It is endemic in the present

scenario is different and sub-tropical regions especially in Asia, Latin America and also in

Africa. Causative of amoebiasis is a protozoan known as Entamoeba histolytica. We screened

all the databases such as PubMed, Science Direct, Medline and Google Scholar by using the

keywords ‘anti-Entamoeba histolytica activity of medicinal plants, anti-Entamoeba histolytica

activity of herbal drugs, the anti-amoebic activity of natural drugs’. In the present study, we

found 7861 articles, where all articles were screened for bias analysis and included 32 fullmatching

articles in total reporting the use of medicinal plants as a remedy for amoebiasis.

Through these articles, we found 42 herbs having anti-amoebic activity. In bias analysis, we

also found four articles under high bias risk. In our study, seven medicinal plants were concluded

to possess the most potent anti-amoebic activity based on their IC50 value, which was

less than 1 μgmL−1. On bias analysis, we found four articles with high bias risk, hence these

studies can be repeated for better results.[9]


We found seven medicinal herbs, including P. anisum, S. cordatum, Virgillia oroboides,

Artemisia sieberi, Kigelia pinnata, Rubus coriifolius and Elaeodendron trichotomum, Piper longum as the most active against E. histolytica having IC50 values below 1 μgmL−1. Active components were also isolated in the studied articles, we found berberin, piperin, alagesan, maackiain, Iroko, chlorophorin, 1-benzopyrylium, artemisia ketone, 1, 8-cineole, minecoside, verminoside,

specioside, globulol, trans-pinocarveol, cocsoline, leucodelphinidin, leucocyanidin, tingenone and pristimerito most active as anti-E. histolytica agents. [9]


In Sum, the potential herbal remedies include:

1. P. anisum (Anise Star, Hawaii pharm}

2. S. cordatum

3. Virgillia oroboides

4. Artemisia sieberi {mugwort, Hawaii Pharm}}

5. Kigelia pinnata {Kigella, Hawaii Pharm}

6. Rubus coriifolius

7. Elaeodendron trichotomum

8. Piper longum {Secrets Of The Tribe, Long pepper}

9. berberin

10. Endemali (herbal product; Kasham.pk}

11. epicatechin {Morinda}

12. kaempferol {Dill}

13. quercetin {same}

14. Camellia sinensis extract {Green Tea Extract}

15. Tamarindus indica {Taramind}


Entamoeba histolytica [10]

Description:

Entameoba histolytica is a single cell parasite from the Protozoan family that may be responsible for inflammation and irritation of the lining of the bowel. Distribution is worldwide. Many animals serve as the main hosts. The organism is usually shed from animal urine.

Transmission:

The usual route of transmission is fecal-oral or accidental ingestion from contaminated food or water.

Prevention:

Good sanitary practices. See Appendix C – Preventive Measures

Symptoms and Clinical Disease:

This organism may cause a variety of problems in the human. Symptoms in the GI tract may range from minor abdominal discomfort to chronic diarrhea. When present in other locations such as the liver or skin symptoms of inflammation of that organ or tissue are present. Immune compromised individuals are more susceptible.


Treatment:

Alternative agents: See Appendix A Alternative/Natural Treatment

Prescriptive agents: Albendazole and other agents. See Appendix B Medical Treatment


For Protozoa:

Argentin 500 (Silver), ACS200 ES (Silver), Formula PZ, Formula HP*, Formula AZ*

Ingredients for PZ: Sweet Basil, Sage Dalmatian, Balsam Fir, Clove Bud , Black Cumin Carrier Oil

Ingredients for AZ: Essential oils of: Coriander, Chamomile, Sweet Thyme, Black Cumin Carrier Oil

Ingredients for HP: Oregon Grape, Wormwood, Black Walnut Hulls, Cat’s Claw , Milk Thistle, Astragalus


Parasites and Me, Hannah Kroeger [11]

Protazoa Entamoeba : Jasmine Tea

If liver infected : Goldenrod, Goldenseal, Cloves


References

[1] Wikepedia

[2] CDC

[3] NIH: Entamoeba histolytica Infection. Arthur Chou; Richard L. Austin. Last Update: April 17, 2023

[5] Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica. Kumiko Nakada-Tsukui. REVIEW article. Front. Immunol., 12 May 2016. Sec. Microbial Immunology. Volume 7 - 2016 | https://doi.org/10.3389/fimmu.2016.00175

[6] A Review: Natural and Synthetic Compounds Targeting Entamoeba histolytica and Its Biological Membrane. by Nurhana Jasni. Membranes 2022, 12(4), 396; https://doi.org/10.3390/membranes12040396. Received: 28 December 2021 / Revised: 23 February 2022 / Accepted: 29 March 2022 / Published: 1 April 2022

[7] Flavonoids as a natural treatment against Entamoeba histolytica. Moisés Martínez-Castillo, Judith Pacheco-Yepez, Nadia Flores-Huerta, et. al. Article number209. Journal Frontiers in Cellular and Infection Microbiology. Volume8. Issue numberJUN. StatePublished - 22 Jun 2018. 10.3389/fcimb.2018.00209

[8] Comparison of allopathic and herbal medicine for the treatment of Entamoeba histolytica; a double blind clinical trial. Alternative & Integrative Medicine. ISSN: 2327-5162. 4th Global Acupuncture & Therapists Annual Meeting and International Conference on Holistic Medicine & Holistic Nursing. July 14-16, 2016 Philadelphia, USA. Muhammad Irfanullah Siddiqui. Umm Al-Qura University, Saudi Arabia.

[9] A systematic review of anti-Entamoeba histolytica activity of medicinal plants published in the last 20 years. Saeed Nezaratizade1 , Nooshin Hashemi, et al. Parasitology 148, 672–684. https://doi.org/10.1017/. S0031182021000172. Received: 6 November 2020

[10] The Amazing World of Parasites, Raphael D'Angelo. By Raphael d’Angelo, MD, MT (AAB).

[11] Parasites and Me, Hannah Kroger

[12] UNDERSTANDING PARASITES IN THE USA by Dr. Omar Amin. A contribution of Parasitology Center, Inc. (PCI). 11445 E. Via Linda, # 2-419. Scottsdale, Arizona 85259

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