A pharmacology-based comparison of the activity of albendazole and flubendazole against Echinococcus granulosus metacestode in sheep

A Review of Approaches to the Metallic and Non-Metallic Synthesis of Benzimidazole (BnZ) and Their Derivatives for Biological Efficacy

Heterocyclic compounds are significant lead drug candidates based on their various structure-activity relationships (SAR), and their use in pharmaceutics is constantly developing. Benzimidazole (BnZ) is synthesized by a condensation reaction between benzene and imidazole. The BnZ structure consists of two nitrogen atoms embedded in a five-membered imide ring which is fused with a benzene ring. This review examines the conventional and green synthesis of metallic and non-metallic BnZ and their derivatives, which have several potential SARs, along with a wide range of pharmacological properties, including anti-cancer, anti-inflammatory, anti-microbial, anti-tubercular, and anti-protozoal properties. These compounds have been proven by pharmacological investigations to be efficient against different strains of microbes. Therefore, in this review, the structural variations of BnZ are listed along with various applications, predominantly related to their biological activities.

Flubendazole, FDA-approved anthelmintic, elicits valid antitumor effects by targeting P53 and promoting ferroptosis in castration-resistant prostate cancer

On account of incurable castration-resistant prostate cancer (CRPC) inevitably developing after treating with androgen deprivation therapy, it is an urgent need to find new therapeutic strategies. Flubendazole is a well-known anti-malarial drug that is recently reported to be a potential anti-tumor agent in various types of human cancer cells. However, whether flubendazole could inhibit the castration-resistant prostate cancer has not been well charified. Thus, the aim of the present study was to characterize the precise mechanism of action of flubendazole on the CRPC. In this study, we investigated the potential effect of flubendazole on cell proliferation, cell cycle and cell death in CRPC cells (PC3 and DU145). We found that flubendazole inhibited cell proliferation, caused cell cycle arrest in G2/M phase and promoted cell death in vitro, and suppressed growth of CRPC tumor in xenograft models. In addition, we reported that flubendazole induced the expression of P53, which partly accounted for the G2/M phase arrest and led to inhibition of the transcription of SLC7A11, and then downregulated the GPX4, which is a major ferroptosis-related gene. Furthermore, flubendazole exhibited synergistic effect with 5-fluorouracil (5-Fu) in chemotherapy of CRPC. This study provides biological evidence that flubendazole is a novel P53 inducer which exerts anti-proliferation and pro-apoptosis effects in CRPC through hindering the cell cycle and activating the ferroptosis, and indicates that a novel utilization of flubendazole in neoadjuvant chemotherapy of CRPC.

Role of anti-filarial drugs in inducing ER stress mediated signaling in bovine filarial parasitosis Setaria cervi

In this ex vivo study, S. cervi parasitoses were treated with Ivermectin (50 μM), Albendazole (200 μM) alone and Ivermectin + Albendazole (50 + 200 μM) at 37°C for 8 h and the motility and viability of the parasitoses were evaluated. Individually both drugs Ivermectin (Iver) and Albendazole (Alb) are reported to affect the function and integrity of ER, however till date, no reports are available on the functional changes in ER due to a combined Iver and Alb treatment of bovine helminth parasitosis. Here, we report the lethal effect of a combination treatment of Iver and Alb against adult bovine filarial parasitosis Setaria cervi. The underlying mechanism of drug action was elucidated by performing a systematic biochemical, molecular and proteomics based study. Altered calcium homeostasis in drug treated parasitoses lead to reduction in levels of total Endoplasmic Reticulum (ER) calcium by 50 % and 61 % and elevation by 50 % and 63 % in cytosol in Iver alone and Iver + Alb treated parasitoses respectively. Further, it was found that upregulated expression of ER localized GRP94, galactosyltransferase and glycosyltransferase activity in addition to reduction in activity of PDI indicated ER stress mechanisms being operative under combined drug treatment. Marked rise of 79 % reactive oxygen species and reduced antioxidant levels induced oxidative stress in drug treated parasitosis. The collective effect of both ER and oxidative stress might have triggered apoptosis, as evidenced by the elevated calpain activity, reduction of 67 % in cytochrome c oxidase and 83 % rise in caspase-3 activity in the Iver + Alb treated parasitoses respectively. The ER proteome analysis by 2D gel electrophoresis revealed 76 spots in the control and 56 spots in the treated proteome. A MALDI-MS/MS analysis of some of the differentially expressed spots of the combination drug treated parasitoses identified glucuronosyltransferase as a major upregulated protein with a fold change of 1.81. Trafficking protein, acyl transferase, MATH involved in protein folding were also found to be downregulated. Thus, this study based on biochemical and proteomic approaches indicates that a combination of anti-filarial drugs Iver and Alb can alter calcium homeostasis in bovine filarial parasitosis leading to induction of ER stress culminating into apoptosis.

Efficacy of novel albendazole salt formulations against secondary cystic echinococcosis in experimentally infected mice

In this study, we evaluated the efficacy, expressed as a mean weight decrease of the whole echinococcal cyst mass, of novel benzimidazole salt formulations in a murine Echinococcus granulosus infection model. BALB/c mice were intraperitoneally infected with protoscoleces of E. granulosus (genotype G1). At 9 months post-infection, treatment with albendazole (ABZ), ricobendazole (RBZ) salt formulations, and RBZ enantiomer salts (R)-(+)-RBZ-Na and (S)-(-)-RBZ-Na formulations were initiated. Drugs were orally applied by gavage at 10 mg kg-1 body weight per day during 30 days. Experimental treatments with benzimidazole sodium salts resulted in a significant reduction of the weight of cysts compared to conventional ABZ treatment, except for the (S)-(-)-RBZ-Na enantiomer formulation. Scanning electron microscopy and histological inspection revealed that treatments impacted not only the structural integrity of the parasite tissue in the germinal layer, but also induced alterations in the laminated layer. Overall, these results demonstrate the improved efficacy of benzimidazole salt formulations compared to conventional ABZ treatment in experimental murine cystic echinococcosis.

Novel Mixed Complexes Derived from Benzoimidazolphenylethanamine and 4-(Benzoimidazol-2-yl)aniline: Synthesis, Characterization, Antibacterial Evaluation and Theoretical Prediction of Toxicity

Benzoimidazolphenylethanamine (BPE) has been synthesized using condensation reaction from o-phenyldiamine and L-phenylalanine. Some metal complexes have been synthesized from 4-(benzoimidazol-2-yl)aniline, benzoimidazolylphenylethanamine and cadmium(II), tin(II), copper(II) and nickel(II) metal in a molar ratio (1:1:1). All new metal complexes were characterized by spectroscopic data of FTIR, UV-visible electronic absorption, X-ray powder diffraction and thermal analysis. Spectra analysis of the mixed metal complexes showed the coordination of ligands to the metal ions via nitrogen atoms. The XRD powder showed that metal complexes have a monoclinic system. The preliminary tested in vitro antibacterial activities of Sn(II) complex was assayed against four bacterial isolates namely Micrococcus luteus, Staphylococcus aureus as Gram-positive, Pseudomonas aerugmosa and Escherichia coli.

Pharmacokinetics and tissue distribution study of liposomal albendazole in naturally Echinococcus granulosus infected sheep by a validated UPLC-Q-TOF-MS method

Albendazole (ABZ) is the first-line drug in treating echinococcosis, which is recommended by WHO. To address the poor bioavailability of albendazole, liposomal albendazole was formulated and is available in our hospital for many years. In this study, a sensitive, reliable and accurate UPLC-Q-TOF-MS method was developed and validated for the determination of albendazole and its metabolites, albendazole sulfoxide (ABZSO), albendazole sulfone (ABZSO₂) and albendazole-2-aminosulfone (ABZSO₂NH₂) in naturally echinococcus granulosus (E. granulosus) infected sheep plasma and tissues with mebendazole (MBZ) as the internal standard (IS). Plasma and tissues samples were prepared by protein precipitation method. The separation was performed on an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 μm) with a gradient mobile phase consisting of methanol and water containing 0.1% formic acid at 0.4 mL/min. The detection was performed on a quadrupole time-of-flight (Q-TOF) high-resolution mass spectrometer using positive electrospray ionization (ESI) source with a chromatographic run time of 6.0 min. The detection was operated using target ions of [M + H]⁺ at m/z 266.096 for ABZ, m/z 282.091 for ABZSO, m/z 298.086 for ABZSO₂, m/z 240.081 for ABZSO₂NH₂ and m/z 296.104 for IS in selective ion mode, respectively. This method was validated in terms of selectivity, linearity, precision, accuracy, recovery, matrix effect, dilution effect, carryover effects, stability, calibration curve and LLOQ. All validation parameter results were within the acceptable range described in guideline for bioanalytical method validation. This method has been successfully applied to the pharmacokinetic study following single and multiple oral dose of 10 mg/kg liposomal albendazole, and tissue distribution study following multiple oral dose of 10 mg/kg, with emulsion albendazole as the reference preparation. The results in the article will provide valuable information for use in clinical applications of liposomal albendazole and also be beneficial for further development of liposomal albendazole in future studies.

Efficiency of flubendazole-loaded mPEG-PCL nanoparticles: A promising formulation against the protoscoleces and cysts of Echinococcus granulosus

None of the existing drugs can effectively treat the human cystic echinococcosis. This study aimed to improve the efficacy of flubendazole (FLBZ) against the protoscoleces and cysts of Echinococcus granulosus by preparing polymeric FLBZ-loaded methoxy polyethylene glycol-polycaprolactone (mPEG-PCL) nanoparticles. The protoscoleces and microcysts were treated with FLBZ-loaded mPEG-PCL nanoparticles (FLBZ-loaded nanoparticles) and free FLBZ at the final concentrations of 1, 5, and 10 μg/mL for 27 and 14 days, respectively. The chemoprophylactic efficacy of the drugs was evaluated in experimentally infected mice. The nanoparticles were stable for 1 month, with an average size of 101.41 ± 5.14 nm and a zeta potential of -19.13 ± 2.56 mV. The drug-loading and entrapment efficiency of the FLBZ-loaded nanoparticles were calculated to be 3.08 ± 0.15% and 89.16 ± 2.93%, respectively. The incubation of the protoscoleces with the 10 μg/mL nano-formulation for 15 days resulted in 100% mortality, while after incubation with the 10 μg/mL free FLBZ, the viability rate of the protoscoleces was only 44.0% ± 5.22%. Destruction of the microcysts was observed after 7 days' exposure to the FLBZ-loaded nanoparticles at a concentration of 10 μg/mL. The in vivo challenge showed a significant reduction in the weight and number of the cysts (P <  0.05) in the mice treated with the FLBZ-loaded nanoparticles, yielding efficacy rates of 94.64% and 70.21%, correspondingly. Transmission electron microscopy revealed extensive ultrastructural damage to the cysts treated with the FLBZ-loaded nanoparticles. The results indicated that the FLBZ-loaded nanoparticles were more effective than the free FLBZ against the protoscoleces and cysts of E. granulosus both in vitro and in vivo.

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.

Flubendazole inhibits glioma proliferation by G2/M cell cycle arrest and pro-apoptosis

Flubendazole, FDA-approved anthelmintic, has been widely used in treating testinal parasites. In the recent years, Flubendazole has been reported to exert anticancer activities. On the other hand, little was known about the effects of Flubendazole on gliomas. Here we demonstrated a novel effect of flubendazole on glioma cells. We found that Flubendazole inhibited cell proliferation and promoted cell apoptosis of glioma cell lines in vitro, and suppressed tumor growth in xenograft models by intraperitoneal injection. However, Flubendazole might have no influence on cell migration. Mechanism study reaveled that Flubendazole caused cell cycle arrest in G2/M phase, which partly account for the suppressed proliferation. Consistently, Flubendazole induced P53 expression and reduced Cyclin B1 and p-cdc2 expression in glioma cells. In addition, Flubendazole promoted cell apoptosis by regulating the classical apoptosis protein BCL-2 expression. These observations suggest that Flubendazole exerts anti-proliferation and pro-apoptosis effects in Glioma through affecting the cell cycle and intrinsic apoptotic signaling, and indicate a novel utilization of Flubendazole in the treatment of Glioma.

The metabolism of flubendazole in human liver and cancer cell lines

Flubendazole (FLU), a benzimidazole anthelmintic drug widely used in veterinary medicine, has been approved for the treatment of gut-residing nematodes in humans. In addition, FLU is now considered a promising anti-cancer agent. Despite this, information about biotransformation of this compound in human is lacking. Moreover, there is no information regarding whether cancer cells are able to metabolize FLU in order to deactivate it. For these reasons, the present study was designed to identify all metabolites of Phase I and Phase II of FLU in human liver and in various cancer cells using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Precision-cut human liver slices and 9 cell lines of different origin (breast, colon, oral cavity) were used as in vitro model systems. Our study showed that FLU with a reduced carbonyl group (FLUR) is the only FLU metabolite formed in the human liver. All human cancer cell lines were able to form FLUR. In addition, methylated FLUR was detected in breast cells MCF7 and intestinal SW480 cells. The accumulation of FLU and its reduction to FLUR markedly differed among cells. The extent of FLU reduction was in a good correlation with the detected expression level of carbonyl reductase 1. In most cases, FLU entered in a higher amount and was reduced to a lesser extent in proliferating (metastatic) cells than in differentiated (non-cancerous, non-metastatic) ones. These results support the promising potential of FLU in anti-cancer therapy.

Construction of In Vivo Fluorescent Imaging of Echinococcus granulosus in a Mouse Model

Human hydatid disease (cystic echinococcosis, CE) is a chronic parasitic infection caused by the larval stage of the cestode Echinococcus granulosus. As the disease mainly affects the liver, approximately 70% of all identified CE cases are detected in this organ. Optical molecular imaging (OMI), a noninvasive imaging technique, has never been used in vivo with the specific molecular markers of CE. Thus, we aimed to construct an in vivo fluorescent imaging mouse model of CE to locate and quantify the presence of the parasites within the liver noninvasively. Drug-treated protoscolices were monitored after marking by JC-1 dye in in vitro and in vivo studies. This work describes for the first time the successful construction of an in vivo model of E. granulosus in a small living experimental animal to achieve dynamic monitoring and observation of multiple time points of the infection course. Using this model, we quantified and analyzed labeled protoscolices based on the intensities of their red and green fluorescence. Interestingly, the ratio of red to green fluorescence intensity not only revealed the location of protoscolices but also determined the viability of the parasites in vivo and in vivo tests. The noninvasive imaging model proposed in this work will be further studied for long-term detection and observation and may potentially be widely utilized in susceptibility testing and therapeutic effect evaluation.

Flubendazole, FDA-approved anthelmintic, targets breast cancer stem-like cells

Cancer stem-like cell (CS-like cell) is considered to be responsible for recurrence and drug resistance events in breast cancer, which makes it a potential target for novel cancer therapeutic strategy. The FDA approved flubendazole, has been widely used in the treatment of intestinal parasites. Here, we demonstrated a novel effect of flubendazole on breast CS-like cells. Flubendazole inhibited breast cancer cells proliferation in dose- and time-dependent manner and delayed tumor growth in xenograft models by intraperitoneal injection. Importantly, flubendazole reduced CD44^high/CD24^low subpopulation and suppressed the formation of mammosphere and the expression of self-renewal related genes including c-myc, oct4, sox2, nanog and cyclinD1. Moreover, we found that flubendazole induced cell differentiation and inhibited cell migration. Consistently, flubendazole reduced mesenchymal markers (β-catenin, N-cadherin and Vimentin) expression and induced epithelial and differentiation marker (Keratin 18) expression in breast cancer cells. Mechanism study revealed that flubendazole arrested cell cycle at G2/M phase and induced monopolar spindle formation through inhibiting tubulin polymerization. Furthermore, flubendazole enhanced cytotoxic activity of conventional therapeutic drugs fluorouracil and doxorubicin against breast cancer cells. In conclusion, our findings uncovered a remarkable effect of flubendazole on suppressing breast CS-like cells, indicating a novel utilization of flubendazole in breast cancer therapy.

Biological Activity and Molecular Structures of Bis(benzimidazole) and Trithiocyanurate Complexes

1-(1H-Benzimidazol-2-yl)-N-(1H-benzimidazol-2-ylmethyl)methanamine (abb) and 2-(1H-benzimidazol-2-ylmethylsulfanylmethyl)-1H-benzimidazole (tbb) have been prepared and characterized by elemental analysis. These bis(benzimidazoles) have been further used in combination with trithiocyanuric acid for the preparation of complexes. The crystal and molecular structures of two of them have been solved. Each nickel atom in the structure of trinuclear complex [Ni₃(abb)₃(H₂O)₃(μ-ttc)](ClO₄)₃·3H₂O·EtOH (1), where ttcH₃ = trithiocyanuric acid, is coordinated with three N atoms of abb, the N,S donor set of ttc anion and an oxygen of a water molecule. The crystal of [(tbbH₂)(ttcH₂)₂(ttcH₃)(H₂O)] (2) is composed of a protonated bis(benzimidazole), two ttcH₂ anions, ttcH₃ and water. The structure is stabilized by a network of hydrogen bonds. These compounds were primarily synthesized for their potential antimicrobial activity and hence their possible use in the treatment of infections caused by bacteria or yeasts (fungi). The antimicrobial and antifungal activity of the prepared compounds have been evaluated on a wide spectrum of bacterial and yeast strains and clinical specimens isolated from patients with infectious wounds and the best antimicrobial properties were observed in strains after the use of ligand abb and complex 1, when at least 80% growth inhibition was achieved.

In vitro treatments of Echinococcus granulosus with fungal chitosan, as a novel biomolecule

OBJECTIVE

To determined the antiparasitic activity of the isolated chitosan from Penicillium viridicatum, Penicillium aurantiogriseum and commercial chitosan against protoscolicidal of hydatid cysts were determined.

METHODS

After isolating chitosan from fungal cell walls, four concentrations (50, 100, 200, 400 μg/mL) of each type of prepared chitosan and commercial chitosan were used for 10, 30, 60, and 180 min, respectively.

RESULTS

Among different type of chitosan, commercial chitosan with the highest degree of deacetylation showed high scolicidal activity in vitro. Fungal chitosan could be recommended, as good as commercial chitosan, for hydatic cysts control.

CONCLUSIONS

It seems to be a good alternative to synthetic and chemical scolicidal.