Genotoxical, teratological and biochemical effects of anthelmintic drug oxfendazole Maximum Residue Limit (MRL) in male and female mice

Oksfendazol, oksiklozanid ve oksfendazol-oksiklozanid kombinasyonunun koyun ve keçilerde biyokimyasal ve hematolojik parametreler üzerine etkileri

Mevcut araştırmada sağlıklı koyun ve keçilere oral yolla oksfendazol, oksiklozanid ve oksfendazol-oksiklozanid kombinasyon uygulamasının, farklı zamanlarda biyokimyasal ve hematolojik parametreler üzerine etkisinin belirlenmesi amaçlandı. Çalışma çapraz dizaynda 6 adet sağlıklı dişi, 1-3 yaştaki İvesi koyun ve Alpin keçi üzerinde gerçekleştirildi. Koyun ve keçilere oral yolla 7.5 mg/kg oksfendazol, 15 mg/kg oksiklozanid ve oksfendazol-oksiklozanid (7.5 mg/kg-15 mg/kg) kombinasyonu uygulandı. Kan örnekleri ilaç uygulamalarından önce (0.saat, kontrol) ve sonraki 8., 24., 72. saat ile 7. günde alındı. Biyokimyasal parametrelerden albümin, alkalen fosfataz, alanin aminotransferaz, aspartat aminotransferaz, kolesterol, trigliserid, total protein, kan üre nitrojen, kreatinin değerleri otoanalizatör cihazında belirlendi. Hematolojik parametrelerden alyuvar sayısı, hemoglobin, hematokrit, ortalama korpüsküler hacim, ortalama korpüsküler hemoglobin, ortalama korpüsküler hemoglobin konsantrasyonu, akyuvar sayısı, lenfosit, monosit, % granülosit, % lenfosit, % monosit ve % eritrosit dağılım genişliği değerleri kan hücresi sayım cihazında ölçüldü. İlaç grupları ve zamana bağlı olarak hematolojik ve serum biyokimya parametrelerinde anlamlı bir fark bulunamadı. Bu sonuçlar koyun ve keçilere oral yolla, 7.5 mg/kg oksfendazol ve 15 mg/kg oksiklozanid tek veya kombine olarak uygulandığında hematolojik ve biyokimyasal parametrelerin fizyolojik sınırlarda olduğu ve klinik olarak anlamlı bir etkisinin olmadığını göstermektedir.

Current perspective on veterinary drug and chemical residues in food of animal origin

The marked increase in the demand for animal protein of high quality necessitates protecting animals from infectious diseases. This requires increasing the use of veterinary therapeutics. The overuse and misuse of veterinary products can cause a risk to human health either as short-term or long-term health problems. However, the biggest problem is the emergence of resistant strains of bacteria or parasites. This is in addition to economic losses due to the discarding of polluted milk or condemnation of affected carcasses. This paper discusses three key points: possible sources of drug and chemical residues, human health problems, and the possible method of control and prevention of veterinary drug residues in animal products.

Anthelmintic activity and non-cytotoxicity of phaeophorbide-a isolated from the leaf of Spondias mombin L

ETHNOPHARMACOLOGICAL RELEVANCE

Helminthosis (worm infection) is a disease of grazing livestock, with significant economic implications. Increasing resistance to existing synthetic anthelmintics used to control helminthosis and the unwanted presence of residues of the anthelmintics reported in meat and dairy products present a serious global health challenge. These challenges have necessitated the development of novel anthelmintics that could combat drug resistance and exhibit better safety profiles. Spondias mombin L. (Anacardiaceae) is a plant that has been used traditionally as a worm expeller.

AIM OF STUDY

The aim of the work reported herein was to isolate and characterise anthelmintic compound(s) from S. mombin leaf, establishing their bioactivity and safety profile.

MATERIALS AND METHODS

Adult Haemonchus placei motility assay was used to assess anthelmintic bioactivity. Bioassay-guided chromatographic fractionation of acetone extract of S. mombin leaf was carried out on a silica gel stationary phase. The structure of the compound was elucidated using spectroscopy (¹H and ¹³C NMR) and Liquid Chromatography-Mass Spectrometry (LC-ESI-MS). Screening to exclude potential cytotoxicity against mammalian cells (H460, Caco-2, MC3T3-E1) was done using alamar blue (AB) and CellTitreGlo (CTG) viability reagents.

RESULTS

The acetone extract yielded an active fraction 8 (Ethyl acetate: methanol 90:10; anthelmintic LC₅₀: 3.97 mg/mL), which yielded an active sub-fraction (Ethyl acetate: Methanol 95:5; anthelmintic LC₅₀: 53.8 μg/mL), from which active compound 1 was isolated and identified as phaeophorbide-a (LC₅₀: 23.0 μg/mL or 38.8 μM). The compound was not toxic below 200 μM but weakly cytotoxic at 200 μM.

CONCLUSIONS

Phaeophorbide-a (1) isolated from S. mombin leaf extract and reported in the plant for the first time in this species demonstrated anthelmintic activity. No significant toxicity to mammalian cells was observed. It therefore represents a novel anthelmintic pharmacophore as a potential lead for the development of novel anthelmintics.

Unravelling the anthelmintic bioactives from Jasminum grandiflorum L. subsp. Floribundum adopting in vitro biological assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Jasminum grandiflorum L. is a medicinal plant widely used in the traditional system of Medicine as an anthelmintic in ringworm infections, for treating ulcers, stomatitis, skin diseases, and wounds.

AIM OF THE STUDY

The emergence of resistance by different parasites to currently used chemicals has been reported. There are increasing needs for more effective and safer parasiticides. Therefore, the current study was designed to investigate the methanolic extract of the aerial parts of J. grandiflorum subsp. Floribundum (JGTE) to confirm its traditional uses as anthelmintic through a bioassay-guided fractionation and isolation of the active components with anthelmintic activity.

MATERIALS AND METHODS

The JGTE was partitioned into dichloromethane (DCM-F) and n-butanol (BuOH-F) fractions. The JGTE, fractions, and the isolated compounds were tested in vitro for their anthelmintic activity using two nematodes; one larval stage of cestode and one arthropod. Four major compounds were isolated from the most active fraction (BuOH-F) including two flavonoids and two secoirridoid glycosides, identified as kaempferol-3-O-neohesperoside (1), rutin (2), oleuropein (3), and ligstroside (4).

RESULTS

Among the isolated compounds from most active fraction (BuOH-F), rutin (2) displayed the highest anthelmintic activity in a dose-dependent activity with IC₅₀ of 41.04 μg/mL against H. muscae adult worm, followed by ligstroside (4) with IC₅₀ of 50.56 μg/mL.

CONCLUSIONS

These findings could advocate the traditional use of J. grandiflorum L. and provide further insight into the anthelmintic activity of flavonoids.

Determination of norfloxacin residues in foods by exploiting the coffee-ring effect and paper-based microfluidics device coupling with smartphone-based detection

By utilizing the coffee-ring effect and microfluidic paper-based analytical devices (µPADs), this study improved the sensitivity of the determination of norfloxacin in four different food matrices. Micro-PADs in this study were fabricated by designing and embedding wax channels onto cellulose-based filter paper through printing and subjecting the paper to heat to allow the wax to penetrate the paper. Determination of norfloxacin concentration in food samples was achieved by monitoring the colorimetric reaction that occurred between norfloxacin and the added iron (III) nitrate nonahydrate in 5 mM ammonia in each reaction chamber. A transition metal hydroxide was formed through this reaction that resulted in the formation of a solid precipitate to enable the antibiotic to bind to the iron molecule via coordination chemistry. This metal ion-antibiotic complex generated a visible color change. Following the colorimetric reaction, images were taken and subsequently analyzed via ImageJ to determine the relative pixel intensity that was used to infer norfloxacin concentration. The analytical sensitivity of this device was determined to be as low as 50 ppm when analyzing the inner-ring reaction, and as low as 5 ppm when analyzing the outer coffee ring thereby allowing for an alternative cheaper, faster, and more user-friendly method to detect norfloxacin than the conventional methods. PRACTICAL APPLICATION: This novel paper-based microfluidic device can achieve the detection of antibiotic residues in agrifoods in a faster, cheaper, and more user-friendly manner.

Anthelmintic drugs used in equine species

Internal parasites of horses comprise an intractable problem conferring disease, production and performance losses. Parasitism can rarely be controlled in grazing horses by management alone and anthelmintic drugs have formed the basis of therapy and prophylaxis for the last sixty years. The pharmacology of the anthelmintic drugs available dictate their spectrum of activity and degree of efficacy, their optimal routes of administration and characteristics which prevent some routes of administration, their safety tolerance and potential toxicities and as a consequence of their persistence in the body at effective concentrations their use in epidemiological control programmes. Their use has also resulted in the selection of parasites with genetically controlled characteristics which reduce their susceptibility to treatment, characteristics which are often common to whole chemical classes of anthelmintics. Pharmacological properties also confer compatibility in terms of safety and persistence with other anthelmintic drugs and thus the potential of combinations to treat parasites from different phylogenetic groups such as nematodes, cestodes and trematodes and also the potential by agency of their different molecular mechanisms of action to delay the selection of resistant genes. The major groups of anthelmintics now available, the benzimidazoles (BZD), macrocyclic lactones (MLs) and tetrahydropyrimidines are all highly effective against their targeted parasites (primarily nematodes for BZD's and ML's and cestodes for tetrahydropyrimidines) easily administered orally to horses and are well tolerated with wide margins of safety. Nevertheless, some parasitic stages are inherently less susceptible such as hypobiotic stages of the small strongyles (cyathostomins) and for some such as the adult stages of cyathostomins resistance has developed. Furthermore, for some less common parasites such as the liver fluke unlicensed drugs such as the salicylanilide, closantel have been used. A deep understanding of the pharmacology of anthelmintic drugs is essential to their optimal use in equine species.

The cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in leatherback sea turtle lung cells

Hexavalent chromium [Cr(VI)] is a marine pollution of concern as recent studies show it has a global distribution, with some regions showing high Cr concentrations in marine animal tissue, and it is extensively used. Leatherback sea turtles (Dermochelys coriacea) are an endangered marine species that may experience prolonged exposures to environmental contaminants including Cr(VI). Human activities have led to global Cr(VI) contamination of the marine environment. While Cr(VI) has been identified as a known human carcinogen, the health effects in marine species are poorly understood. In this study, we assessed the cytotoxic and genotoxic effects of particulate and soluble Cr(VI) in leatherback sea turtle lung cells. Both particulate and soluble Cr(VI) induced a concentration-dependent increase in cytotoxicity. Next, using a chromosome aberration assay, we assessed the genotoxic effects of Cr(VI) in leatherback sea turtle lung cells. Particulate and soluble Cr(VI) induced a concentration-dependent increase in clastogenicity in leatherback sea turtle lung cells. These data indicate that Cr(VI) may be a health concern for leatherback sea turtles and other long-lived marine species. Additionally, these data provide foundational support to use leatherback sea turtles as a valuable model species for monitoring the health effects of Cr(VI) in the environment and possibly as an indicator species to assess environmental human exposures and effects.

A Novel Strategy to Predict Carcinogenicity of Antiparasitics Based on a Combination of DNA Lesions and Bacterial Mutagenicity Tests

Genotoxicity and carcinogenicity testing of pharmaceuticals prior to commercialization is requested by regulatory agencies. The bacterial mutagenicity test was considered having the highest accuracy of carcinogenic prediction. However, some evidences suggest that it always results in false-positive responses when the bacterial mutagenicity test is used to predict carcinogenicity. Along with major changes made to the International Committee on Harmonization guidance on genotoxicity testing [S2 (R1)], the old data (especially the cytotgenetic data) may not meet current guidelines. This review provides a compendium of retrievable results of genotoxicity and animal carcinogenicity of 136 antiparasitics. Neither genotoxicity nor carcinogenicity data is available for 84 (61.8%), while 52 (38.2%) have been evaluated in at least one genotoxicity or carcinogenicity study, and only 20 (14.7%) in both genotoxicity and carcinogenicity studies. Among 33 antiparasitics with at least one old result in in vitro genotoxicity, 15 (45.5%) are in agreement with the current ICH S2 (R1) guidance for data acceptance. Compared with other genotoxicity assays, the DNA lesions can significantly increase the accuracy of prediction of carcinogenicity. Together, a combination of DNA lesion and bacterial tests is a more accurate way to predict carcinogenicity.

Triclabendazole sulfoxide causes stage-dependent embryolethality in zebrafish and mouse in vitro

Background

Fascioliasis and paragonimiasis are widespread foodborne trematode diseases, affecting millions of people in more than 75 countries. The treatment of choice for these parasitic diseases is based on triclabendazole, a benzimidazole derivative which has been suggested as a promising drug to treat pregnant women and children. However, at the moment, this drug is not approved for human use in most countries. Its potential adverse effects on embryonic development have been scarcely studied, and it has not been assigned a pregnancy category by the FDA. Thus, to help in the process of risk-benefit decision making upon triclabendazole treatment during pregnancy, a better characterization of its risks during gestation is needed.

Methodology

The zebrafish embryo test, a preimplantation and a postimplantation rodent whole embryo culture were used to investigate the potential embryotoxicity/teratogenicity of triclabendazole and its first metabolite triclabendazole sulfoxide. Albendazole and albendazole sulfoxide were included as positive controls.

Principal Findings

Triclabendazole was between 10 and 250 times less potent than albendazole in inducing dysmorphogenic effects in zebrafish or postimplantation rodent embryos, respectively. However, during the preimplantation period, both compounds, triclabendazole and triclabendazole sulfoxide, induced a dose-dependent embryolethal effect after only 24 h of exposure in rodent embryos and zebrafish (lowest observed adverse effect concentrations = 10 μM).

Conclusions/Significance

In humans, after ingestion of the recommended doses of triclabendazole to treat fascioliasis and paragonimiasis (10 mg/kg), the main compound found in plasma is triclabendazole sulfoxide (maximum concentration 38.6 μM), while triclabendazole concentrations are approximately 30 times lower (1.16 μM). From our results it can be concluded that triclabendazole, at concentrations of the same order of magnitude as the clinically relevant ones, does not entail teratogenic potential in vitro during the organogenesis period, but its first metabolite triclabendazole sulfoxide has a high embryotoxic capacity in vitro during the preimplantation stage.

Preclinical studies on the pharmacokinetics, safety, and toxicology of oxfendazole: toward first in human studies

A 2-week study in rats identified target organs of oxfendazole toxicity to be bone marrow, epididymis, liver, spleen, testis, and thymus. Female rats had greater oxfendazole exposure and exhibited toxicities at lower doses than did males. Decreased white blood cell levels, a class effect of benzimidazole anthelmintics, returned to normal during the recovery period. The no observed adverse effect level was determined to be >5 but <25 mg/kg/d and the maximum tolerated dose 100 mg/kg/d. The highest dose, 200 mg/kg/d, resulted in significant toxicity and mortality, leading to euthanization of the main study animals in this group after 7 days. Oxfendazole did not exhibit genetic toxicology signals in standard Ames bacterial, mouse lymphoma, or rat micronucleus assays nor did it provoke safety concerns when evaluated for behavioral effects in rats or cardiovascular safety effects in dogs. These results support the transition of oxfendazole to First in Human safety studies preliminary to its evaluation in human helminth diseases.

Hexavalent chromium is cytotoxic and genotoxic to hawksbill sea turtle cells

Sea turtles are a charismatic and ancient ocean species and can serve as key indicators for ocean ecosystems, including coral reefs and sea grass beds as well as coastal beaches. Genotoxicity studies in the species are absent, limiting our understanding of the impact of environmental toxicants on sea turtles. Hexavalent chromium (Cr(VI)) is a ubiquitous environmental problem worldwide, and recent studies show it is a global marine pollutant of concern. Thus, we evaluated the cytotoxicity and genotoxicity of soluble and particulate Cr(VI) in hawksbill sea turtle cells. Particulate Cr(VI) was both cytotoxic and genotoxic to sea turtle cells. Concentrations of 0.1, 0.5, 1, and 5μg/cm(2) lead chromate induced 108, 79, 54, and 7% relative survival, respectively. Additionally, concentrations of 0, 0.1, 0.5, 1, and 5μg/cm(2) lead chromate induced damage in 4, 10, 15, 26, and 36% of cells and caused 4, 11, 17, 30, and 56 chromosome aberrations in 100 metaphases, respectively. For soluble Cr, concentrations of 0.25, 0.5, 1, 2.5, and 5μM sodium chromate induced 84, 69, 46, 25, and 3% relative survival, respectively. Sodium chromate induced 3, 9, 9, 14, 21, and 29% of metaphases with damage, and caused 3, 10, 10, 16, 26, and 39 damaged chromosomes in 100 metaphases at concentrations of 0, 0.25, 0.5, 1, 2.5, and 5μM sodium chromate, respectively. These data suggest that Cr(VI) may be a concern for hawksbill sea turtles and sea turtles in general.

Chemical dispersants used in the Gulf of Mexico oil crisis are cytotoxic and genotoxic to sperm whale skin cells

The 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico drew attention to the need for toxicological studies of chemical dispersants. We are still learning the effects these spills had on wildlife. Little is known about the toxicity of these substances in marine mammals. The objective of this study was to determine the toxicity of the two dispersants (Corexit 9500 and 9527). Corexit 9500 and 9527 were both cytotoxic to sperm whale skin fibroblasts. Corexit 9527 was less cytotoxic than 9500. S9 mediated metabolism did not alter cytotoxicity of either dispersant. Both dispersants were genotoxic to sperm whale skin fibroblasts; S9 mediated metabolism increased Corexit 9527 genotoxicity.

The toxicity and adverse effects of selected drugs in animals – overview

Therapeutic products quite often are causes of poisoning in both small and large animals. Drug poisonings in animals occur commonly due to off-label use of medicines, wrong dosage, negligence, accidental ingestion and deliberate poisonings. Toxicity of veterinary drugs may become evident also in therapeutic doses when adverse effects may occur. The aim of this review is to inform veterinary specialists about both veterinary and human drugs, specifically antiparasitics, non-steroidal anti-inflammatory drugs and other medicinal substances, which are most often reported to cause acute poisonings or adverse reactions in animals and to contribute to their broader knowledge and more accurate use of medicines, improving instructions to the animal owners and, hopefully, decrease the incidence of drug poisonings in animals.

Development of an Evidence biochip array kit for the multiplex screening of more than 20 anthelmintic drugs

Anthelmintic drugs are used in clinical and veterinary practice for the treatment of infections caused by parasitic worms. Their extensive use in food-producing animals can cause the presence of residues in food. For consumer protection it is necessary to monitor the levels of anthelmintic residues to ensure that they remain within the legally permitted maximum acceptable concentrations. For this purpose, the use of multiplex screening methods is advantageous. Biochip array technology allows the simultaneous determination of multiple analytes from a single sample at a single point in time. This study reports the development of an Evidence biochip array for the multiplex screening of anthelmintic drugs. Simultaneous competitive chemiluminescent immunoassays are employed. The solid support and vessel is the biochip, which contains an array of discrete test sites. The assays were applied to the semiautomated bench-top analyser Evidence Investigator. The aminobenzimidazoles assay detected aminomebendazole, albendazole 2-aminosulphone and aminoflubendazole, the avermectins assay detected emamectin benzoate, eprinomectin, abamectin, ivermectin and doramectin, the benzimidazoles assay detected albendazole sulphone, albendazole, albendazole sulphoxide, oxibendazole, oxfendazole and flubendazole, the thiabendazole assay detected cambendazole, thiabendazole and 5-hydroxythiabendazole and the triclabendazole assay detected ketotriclabendazole, triclabendazole and triclabendazole sulphoxide. The limits of detection ranged from 0.3 ppb (aminobenzimidazoles) to 2.0 ppb (levamisole) in milk and from 0.15 ppb (aminobenzimidazoles) to 6.5 ppb (levamisole) in tissue. The average recovery range was 71-135 %. This multianalytical approach on a biochip platform is applicable to the screening of more than 20 anthelmintic drugs in different food matrices, leading to consolidation of tests and enhancement of the test result output.

Immunohistochemical analyses at the late stage of tumor promotion by oxfendazole in a rat hepatocarcinogenesis model

The present study was performed to characterize immunohistochemically the expression levels of molecules related to not only xenobiotic and antioxidant functions but also cell proliferation and apoptosis in neoplastic lesions induced by the benzimidazole anthelmintic, oxfendazole (OX), at the late stage of its tumor promotion in a rat hepatocarcinogenesis model. Male F344 rats were initiated with an intraperitoneal injection of 200 mg/kg N-diethylnitrosamine, and 2 weeks later they were fed a diet containing 0% (basal diet) or 0.05% OX for 26 weeks. All animals were subjected to a two-thirds partial hepatectomy at week 3 and killed at week 28. Histopathologically, OX increased the incidence and multiplicity of altered foci (4.0- and 3.6-fold, respectively) and hepatocellular adenomas (HCAs) (3.0- and 5.5-fold, respectively). OX treatment induced 5.2- and 5.6-fold increases in the number of proliferating cell nuclear antigen (PCNA)-positive cells and single-stranded DNA (ssDNA)-positive cells in HCAs compared with the surrounding tissue, respectively. Staining for the cell cycle regulators P21 and C/EBPα and the AhR-regulated CYP1A1 molecules decreased but increased reactivity of the Nrf2-regulated, detoxifing/antioxidant molecules aldo-keto reductase 7 (AKR7) and glutathione peroxidase 2 (GPX2) were also seen in HCAs compared with the surrounding hepatocytes. These results suggest that dysregulation of cell proliferation and apoptosis and escape from oxidative stress elicited by OX treatment play an important role in OX-induced hepatocarcinogenesis in rats.

Towards novel antifilarial drugs: challenges and recent developments

Filariasis is caused by thread-like nematode worms, classified according to their presence in the vertebrate host. The cutaneous group includes Onchocerca volvulus, Loa loa and Mansonella streptocerca; the lymphatic group includes Wuchereria bancrofti, Brugia malayi and Brugia timori and the body cavity group includes Mansonella perstans and Mansonella ozzardi. Lymphatic filariasis, a mosquito-borne disease, is one of the most prevalent diseases in tropical and subtropical countries and is accompanied by a number of pathological conditions. In recent years, there has been rapid progress in filariasis research, which has provided new insights into the pathogenesis of filarial disease, diagnosis, chemotherapy, the host–parasite relationship and the genomics of the parasite. Together, these insights are assisting the identification of novel drug targets and the discovery of antifilarial agents and candidate vaccine molecules. This review discusses the antifilarial activity of various chemical entities, the merits and demerits of antifilarial drugs currently in use, their mechanisms of action, in addition to antifilarial drug targets and their validation.

UMF-078: A modified flubendazole with potent macrofilaricidal activity against Onchocerca ochengi in African cattle

BACKGROUND

Human onchocerciasis or river blindness, caused by the filarial nematode Onchocerca volvulus, is currently controlled using the microfilaricidal drug, ivermectin. However, ivermectin does not kill adult O. volvulus, and in areas with less than 65% ivermectin coverage of the population, there is no effect on transmission. Therefore, there is still a need for a macrofilaricidal drug. Using the bovine filarial nematode O. ochengi (found naturally in African cattle), the macrofilaricidal efficacy of the modified flubendazole, UMF-078, was investigated.

METHODS

Groups of 3 cows were treated with one of the following regimens: (a) a single dose of UMF-078 at 150 mg/kg intramuscularly (im), (b) 50 mg/kg im, (c) 150 mg/kg intraabomasally (ia), (d) 50 mg/kg ia, or (e) not treated (controls).

RESULTS

After treatment at 150 mg/kg im, nodule diameter, worm motility and worm viability (as measured by metabolic reduction of tetrazolium to formazan) declined significantly compared with pre-treatment values and concurrent controls. There was abrogation of embryogenesis and death of all adult worms by 24 weeks post-treatment (pt). Animals treated at 50 mg/kg im showed a decline in nodule diameter together with abrogated reproduction, reduced motility, and lower metabolic activity in isolated worms, culminating in approximately 50% worm mortality by 52 weeks pt. Worms removed from animals treated ia were not killed, but exhibited a temporary embryotoxic effect which had waned by 12 weeks pt in the 50 mg/kg ia group and by 24 weeks pt in the 150 mg/kg ia group. These differences could be explained by the different absorption rates and elimination half-lives for each dose and route of administration.

CONCLUSION

Although we did not observe any signs of mammalian toxicity in this trial with a single dose, other studies have raised concerns regarding neuro- and genotoxicity. Consequently, further evaluation of this compound has been suspended. Nonetheless, these results validate the molecular target of the benzimidazoles as a promising lead for rational design of macrofilaricidal drugs.