Effect of Different Terpene-Containing Essential Oils on the Proliferation of Echinococcus granulosus Larval Cells

Scolicidal and apoptotic effects of phyto- and chemically synthesized silver/boehmite nanocomposites on Echinococcus granulosus protoscoleces

Cystic hydatid disease (CHD) is a zoonotic disease caused by the larval stage of Echinococcus granulosus (E. granulosus). This study aimed to synthesize silver nanoparticles (Ag NPs), silver boehmite nanocomposite (Ag/Bhm NC), and silver boehmite nanocomposite modified with chitosan (Ag/Bhm/Chit NC) using Rosmarinus officinalis (R. officinalis) extract and chemical method, and to evaluate their scolicidal and apoptotic effects on protoscoleces (PSCs) in vitro. The nanomaterials (NMs) were characterized by XRD, FTIR, FESEM, EDS, DLS, PDI, and zeta potential (ZP). The NMs were tested against PSCs at different concentrations (0.2-1.6 mg/mL) and exposure times (10-60 min). The size of Ag NPs, phytosynthesized Ag/Bhm NC, Ag/Bhm/Chit NC, and chemically synthesized Ag/Bhm NC were 25.55, 43, 72.3, and 60.8 nm, respectively. Ag NPs and phytosynthesized Ag/Bhm NC showed the highest scolicidal effect, with 65.34 % and 51.60 % mortality rate at 1.6 mg/mL and 60 min, respectively. Caspase-3 mRNA expression was higher in PSCs treated with Ag NPs and Ag/Bhm NC than in control groups (P < 0.05). Phytosynthesized Ag/Bhm NC had stronger scolicidal and apoptotic effect than chemically synthesized Ag/Bhm NC. Ag/Bhm/Chit NC had a weaker scolicidal effect but higher gene expression than Ag/Bhm NC. In conclusion, this study demonstrates the potential of phytosynthesized Ag NPs and Ag/Bhm NC as effective scolicidal and apoptotic agents against PSCs of hydatid cysts, which may be useful for the treatment of this disease.

Status and prospect of novel treatment options toward alveolar and cystic echinococcosis

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are the two most important global parasitic infectious diseases caused by species of Echinococcus granulosus and E. multilocularis, respectively. Although numerous trials have been performed in search of novel therapeutic options to curb the neglected zoonosis, no other nonsurgical options are currently available to replace the licensed anti echinococcal drugs albendazole (ABZ) and mebendazole (MBZ). A safer and more effective treatment plan for echinococcosis is therefore urgently needed to compensate for this therapeutic shortfall. Here, we present a review of the literature for state-of-the-art valuable anti-parasitic compounds and novel strategies that have proved effective against CE and AE, which includes details about the pharmaceutical type, practical approach, experimental plan, model application and protoscolecidal effects in vivo and in vitro. The content includes the current application of traditional clinical chemicals, the preparation of new compounds with various drug loadings, repurposing findings, combined programs, the prospects for Chinese herbal medicines, non-drug administrations and the exploration of target inhibitors based on open-source information for parasitic genes. Next the conventional experimental projects and pharmacodynamic evaluation methods are systematically summarized and evaluated. The demands to optimize the construction of the echinococcosis model and improve the dynamic monitoring method in vivo are also discussed given the shortcomings of in vivo models and monitoring methods.

A systematic review of medicinal plants used against Echinococcus granulosus

Cystic echinococcosis (CE) is a zoonotic helminthiasis caused by different species of the genus Echinococcus, and is a major economic and public health concern worldwide. Synthetic anthelmintics are most commonly used to control CE, however, prolonged use of these drugs may result in many adverse effects. This study aims to discuss the in vitro/in vivo scolicidal efficacy of different medicinal plants and their components used against Echinococcus granulosus. Google Scholar, ScienceDirect, PubMed and Scopus were used to retrieve the published literature from 2000-2020. A total of 62 published articles met the eligibility criteria and were reviewed. A total of 52 plant species belonging to 22 families have been reported to be evaluated as scolicidal agents against E. granulosus worldwide. Most extensively used medicinal plants against E. granulosus belong to the family Lamiaceae (25.0%) followed by Apiaceae (11.3%). Among various plant parts, leaves (36.0%) were most commonly used. Essential oils of Zataria multiflora and Ferula asafetida at a concentration of 0.02, and 0.06 mg/ml showed 100% in vitro scolicidal activity after 10 min post application, respectively. Z. multiflora also depicted high in vivo efficacy by decreasing weight and size while also causing extensive damage to the germinal layer of the cysts. Plant-based compounds like berberine, thymol, and thymoquinone have shown high efficacy against E. granulosus. These plant species and compounds could be potentially used for the development of an effective drug against E. granulosus, if further investigated for in vivo efficacy, toxicity, and mechanism of drug action in future research.

In vitro efficacy study of Cinnamomum zeylanicum essential oil and cinnamaldehyde against the larval stage of Echinococcus granulosus

Hydatidosis or cystic echinococcosis is a disease caused by the larval stage of Echinococcus granulosus sensu lato. Chemotherapy can be used alone or in combination with surgery or percutaneous treatment. Benzimidazoles are the only agents used and approved for treatment, but their efficacy is extremely variable. Therefore, it is necessary to find new drugs to improve the treatment of this disease. In the last decades, the biological properties of essential oils and their components began to be investigated as alternatives in the treatment of different ailments. The aim of the present work was to evaluate the in vitro efficacy of the essential oil of Cinnamomum zeylanicum (cinnamon) and cinnamaldehyde against protoscoleces and metacestodes of E. granulosus. The essential oil and cinnamaldehyde, its major component, showed a dose and time dependent effect against protoscoleces. However, cinnamaldehyde showed a greater protoscolicidal effect than the essential oil. The maximum protoscolicidal effect was found with 50 μg/mL of cinnamaldehyde. Viability decreased by 1.7 ± 0.8% after 4 days of incubation and reached 0% at 8 days. Interestingly, there were no significant differences between the activity of cinnamaldehyde at the concentrations of 25 and 10 μg/mL and the efficacy observed with the essential oil at 200 and 50 μg/mL, respectively. Cinnamaldehyde also had a strong in vitro effect against murine cysts, while only the higher concentration of the essential oil caused ultrastructural alterations. Working with components instead of with essential oils has some advantages, particularly in relation to the reproducibility of the formulations and their effectiveness. For this reason, the results obtained in this work are promising in the search for pharmaceutical alternatives for the treatment of cystic echinococcosis.

Could beta-myrcene be an alternative to albendazole for the treatment of experimental cystic echinococcosis?

Echinococcus granulosus causes hydatidosis or cystic echinococcosis in humans and livestock. In humans, this disease can be managed with surgery, percutaneous treatment, chemotherapy and/or observation. The chemotherapeutic agents used and approved for treatment of hydatidosis are benzimidazoles. Because of the difficulties in achieving successful treatment, considerable efforts have been made to find new natural compounds against hydatid disease. Beta-myrcene is a monoterpene presented in the essential oils of different plants. It is the principal component of essential oil of Rosmarinus officinalis (rosemary). The goal of the present study was to evaluate the in vitro effects of beta-myrcene against germinal cells, protoscoleces and murine cyst of E. granulosus, as well also, investigate its chemoprophylactic activity in a murine model of cystic echinococcosis. For the in vitro assays, the parasites were incubated with beta-myrcene at 10, 5 and 1 μg/mL. The treatments were dose and time-dependent, and consistent with the observed morphological alterations. In the chemoprophylactic efficacy study, the effect of beta-myrcene was similar to albendazole, the reference drug for human echinococcosis treatment.

Progress in the pharmacological treatment of human cystic and alveolar echinococcosis: Compounds and therapeutic targets

Human cystic and alveolar echinococcosis are helmintic zoonotic diseases caused by infections with the larval stages of the cestode parasites Echinococcus granulosus and E. multilocularis, respectively. Both diseases are progressive and chronic, and often fatal if left unattended for E. multilocularis. As a treatment approach, chemotherapy against these orphan and neglected diseases has been available for more than 40 years. However, drug options were limited to the benzimidazoles albendazole and mebendazole, the only chemical compounds currently licensed for treatment in humans. To compensate this therapeutic shortfall, new treatment alternatives are urgently needed, including the identification, development, and assessment of novel compound classes and drug targets. Here is presented a thorough overview of the range of compounds that have been tested against E. granulosus and E. multilocularis in recent years, including in vitro and in vivo data on their mode of action, dosage, administration regimen, therapeutic outcomes, and associated clinical symptoms. Drugs covered included albendazole, mebendazole, and other members of the benzimidazole family and their derivatives, including improved formulations and combined therapies with other biocidal agents. Chemically synthetized molecules previously known to be effective against other infectious and non-infectious conditions such as anti-virals, antibiotics, anti-parasites, anti-mycotics, and anti-neoplastics are addressed. In view of their increasing relevance, natural occurring compounds derived from plant and fungal extracts are also discussed. Special attention has been paid to the recent application of genomic science on drug discovery and clinical medicine, particularly through the identification of small inhibitor molecules tackling key metabolic enzymes or signalling pathways.

Human cystic and alveolar echinococcosis (CE and AE), caused by the larval stages of the helminths Echinococcus granulosus and E. multilocularis, respectively, are progressive and chronic diseases affecting more than 1 million people worldwide. Both are considered orphan and neglected diseases by the World Health Organization. As a treatment approach, chemotherapy is limited to the use of benzimidazoles, drugs that stop parasite growth but do not kill the parasite. To compensate this therapeutic shortfall, new treatment alternatives are urgently needed. Here, we present the state-of-the-art regarding the alternative compounds and new formulations of benzimidazoles assayed against these diseases until now. Some of these new and modified compounds, either alone or in combination, could represent a step forward in the treatment of CE and AE. Unfortunately, few compounds have reached clinical trials stage in humans and, when assayed, the design of these studies has not allowed evidence-based conclusions. Thus, there is still an urgent need for defining new compounds or improved formulations of those already assayed, and also for a careful design of clinical protocols that could lead to the draw of a broad international consensus on the use of a defined drug, or a combination of drugs, for the effective treatment of CE and AE.

Natural products applied against hydatid cyst protoscolices: A review of past to present

Echinococcus granulosus is the causative agent of cystic echinococcosis (CE), which is distributed all around the world. CE is one of the most important global parasitic infectious diseases, both in humans and animals. This parasite causes hydatid cysts that can be lodge at different organs of host such as liver, lung even in heart and brain which may lead to death. Presently, numerous scolicidal chemical agents have been administrated for inactivation of the hydatid cyst contents. Because of increasing resistance and adverse effects of medications include abnormalities of liver function, abdominal pain, diarrhea, nausea, vomiting, dizziness, and headache; there is a need to find alternative therapies either with the least or without side effects. Recently, there is a high tendency among researchers to evaluate and present herbal plants as alternative option due to being inexpensive, easy available, low side effects and toxicity. Till now, many efforts have been conducted on herbal extracts against protoscolices of hydatid cysts throughout the world. Therefore, the current review systematically searched the following electronic databases: PubMed, Science Direct, Scopus, and Google Scholar on published papers according to the keywords. In addition, a comprehensive list of medicinal plants was prepared and some of these herbal plants which showed the best efficacy and promising results are discussed elaborately.

Gamma-Ray Treatment of Echinococcus Protoscoleces prior to Implantation in Mice Reduces Echinococcosis

Echinococcosis is a serious parasitic disease caused by Echinococcus tapeworms. Protoscoleces are sometimes released during surgical treatment for hydatid cysts, causing the recurrence of echinococcosis. Protoscoleces may be susceptible to radiation therapy. In this study Echinococcus protoscoleces were cultured in vitro and then divided into four different γ-ray irradiation dose groups (10 Gy, 20 Gy, 40 Gy, and 80 Gy) and a blank group. The protoscoleces were then implanted into the abdominal cavity of mice. Four months later, we observed that the incidence and weight of cysts declined with the increase of irradiation dose. γ-ray irradiation can suppress the generation of Echinococcus originated from protoscolex, the reason of which is due to the damaging to the structure of Echinococcus. Irradiation may prevent echinococcosis recurrence after surgical removal of hydatid cysts.

In vivo activity of albendazole in combination with thymol against Echinococcus multilocularis

Human alveolar echinococcosis (AE) is caused by the fox tapeworm Echinococcus multilocularis and is usually lethal if left untreated. The current strategy for treating human AE is surgical resection of the parasite mass complemented by chemotherapy with benzimidazole compounds. However, reliable chemotherapeutic alternatives have not yet been developed stimulating the research of new treatment strategies such as the use of medicinal plants. The aim of the current study was to investigate the efficacy of the combination albendazole (ABZ)+thymol on mice infected with E. multilocularis metacestodes. For this purpose, mice infected with parasite material were treated daily for 20 days with ABZ (5 mg/kg), thymol (40 mg/kg) or ABZ (5 mg/kg)+thymol (40 mg/kg) or left untreated as controls. After mice were euthanized, cysts were removed from the peritoneal cavity and the treatment efficacy was evaluated by the mean cysts weight, viability of protoscoleces and ultrastructural changes of cysts and protoscoleces. The application of thymol or the combination of ABZ+thymol resulted in a significant reduction of the cysts weight compared to untreated mice. We also found that although ABZ and thymol had a scolicidal effect, the combination of the two compounds had a considerably stronger effect showing a reduction in the protoscoleces viability of 62%. These results were also corroborated by optical microscopy, SEM and TEM. Protoscoleces recovered from ABZ or thymol treated mice showed alterations as contraction of the soma region, rostellar disorganization and presence of blebs in the tegument. However both drugs when combined lead to a total loss of the typical morphology of protoscoleces. All cysts removed from control mice appeared intact and no change in ultrastructure was detected. In contrast, cysts developed in mice treated with ABZ revealed changes in the germinal layer as reduction in cell number, while the treatment with thymol or the ABZ+thymol combination predominantly showed presence of cell debris. On the other hand, no differences were found in alkaline phosphatase (AP), glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities between control and treated mice, indicating the lack of toxicity of the different drug treatments during the experiment. Because combined ABZ+thymol treatment exhibited higher treatment efficiency compared with the drugs applied separately against murine experimental alveolar echinococcosis, we propose it would be a useful option for the treatment of human AE.