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1.
Open Vet J ; 14(3): 866-878, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38682137

RESUMEN

Background: Cystic echinococcosis (CE), which is triggered by the parasite Echinococcus granulosus, is a global zoonotic disease that is common in rural regions in which there are frequent encounters between dogs and other domestic animals. The disease can have devastating consequences, impacting the health of people and animals and leading to huge financial losses, especially in the agricultural industry. In the Kingdom of Saudi Arabia (KSA) and Egypt, despite the high incidence of disease, few investigations have been conducted into the genetic variation in species of the genus Echinococcus. Aim: This study sought to compare the genetic features of the hydatid cysts carried in sheep in KSA with those found in Egypt. Methods: DNA from the protoscolices was used in a PCR targeting the mitochondrial NADH dehydrogenase 1 (NAD1), cytochrome c oxidase subunit 1 (COX1), and nuclear actin II (ACT II) genes, and the resulting amplification products of 30 KSA and Egyptian isolates were sequenced and compared. Results: Among the sheep in KSA, the overall prevalence of CE was 0.51%. Of the sheep cyst DNA samples, 95%, 100%, and 52% were positive for the Cox1, nad1, and act II genes, respectively. Targeting all three genes, all KSA samples belonged to the E. granulosus genotype (G1), whereas all Egyptian isolates belonged to E. granulosus (G1) and E. canadensis (G6). Conclusion: We conclude that isolates of E. granulosus from the two countries shared a common origin in Arabic North Africa, with sheep and camels as common hosts.


Asunto(s)
Equinococosis , Echinococcus granulosus , Genotipo , Enfermedades de las Ovejas , Animales , Echinococcus granulosus/genética , Echinococcus granulosus/aislamiento & purificación , Equinococosis/veterinaria , Equinococosis/epidemiología , Equinococosis/parasitología , Ovinos , Egipto/epidemiología , Enfermedades de las Ovejas/parasitología , Enfermedades de las Ovejas/epidemiología , Arabia Saudita/epidemiología , Prevalencia
2.
Front Vet Sci ; 11: 1357947, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38496314

RESUMEN

Toxoplasmosis continues to be a prevalent parasitic zoonosis with a global distribution. This disease is caused by an intracellular parasite known as Toxoplasma gondii, and the development of effective novel drug targets to combat it is imperative. There is limited information available on the potential advantages of wheat germ oil (WGO) and propolis, both individually and in combination, against the acute phase of toxoplasmosis. In this study, acute toxoplasmosis was induced in Swiss albino mice, followed by the treatment of infected animals with WGO and propolis, either separately or in combination. After 10 days of experimental infection and treatment, mice from all groups were sacrificed, and their brains, uteri, and kidneys were excised for histopathological assessment. Additionally, the average parasite load in the brain was determined through parasitological assessment, and quantification of the parasite was performed using Real-Time Polymerase Chain Reaction targeting gene amplification. Remarkably, the study found that treating infected animals with wheat germ oil and propolis significantly reduced the parasite load compared to the control group that was infected but not treated. Moreover, the group treated with a combination of wheat germ oil and propolis exhibited a markedly greater reduction in parasitic load compared to the other groups. Similarly, the combination treatment effectively restored the histopathological changes observed in the brain, uterus, and kidney, and the scoring of these reported lesions confirmed these findings. In summary, the present results reveal intriguing insights into the potential therapeutic benefits of wheat germ oil and propolis in the treatment of acute toxoplasmosis.

3.
Molecules ; 28(12)2023 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-37375205

RESUMEN

Current medication therapy for leishmaniasis and trypanosomiasis remains a major challenge due to its limited efficacy, significant adverse effects, and inaccessibility. Consequently, locating affordable and effective medications is a pressing concern. Because of their easy-to-understand structure and high functionalization potential, chalcones are promising candidates for use as bioactive agents. Thirteen synthetic ligustrazine-containing chalcones were evaluated for their ability to inhibit the growth of leishmaniasis and trypanosomiasis in etiologic agents. The tetramethylpyrazine (TMP) analogue ligustrazine was chosen as the central moiety for the synthesis of these chalcone compounds. The most effective compound (EC50 = 2.59 µM) was the chalcone derivative 2c, which featured a pyrazin-2-yl amino on the ketone ring and a methyl substitution. Multiple actions were observed for certain derivatives, including 1c, 2a-c, 4b, and 5b, against all strains tested. Eflornithine served as a positive control, and three ligustrazine-based chalcone derivatives, including 1c, 2c, and 4b, had a higher relative potency. Compounds 1c and 2c are particularly efficacious; even more potent than the positive control, they are therefore promising candidates for the treatment of trypanosomiasis and leishmaniasis.


Asunto(s)
Chalcona , Chalconas , Leishmania , Leishmaniasis , Trypanosoma brucei brucei , Tripanosomiasis , Humanos , Chalcona/farmacología , Chalcona/uso terapéutico , Chalconas/química , Tripanosomiasis/tratamiento farmacológico , Leishmaniasis/tratamiento farmacológico
4.
Animals (Basel) ; 12(22)2022 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-36428412

RESUMEN

Avian coccidiosis remains one of the major parasitic diseases that threaten the global poultry industry. Since prevention is superior to treatment, this study focuses on eliminating the infection outside the host. To determine their effect on the viability of Eimeria tenella oocysts in vitro, allicin and alcoholic garlic extract, which are natural, less toxic, and inexpensive products, were compared to KOH 5% (chemical disinfectant) using an in vitro culture system. Three concentrations of allicin (45, 90, and 180 mg/mL) and alcoholic garlic extract (90, 180, and 360 mg/mL, were used. Subsequently, destructive and sporulation-inhibiting effects on Eimeria oocysts were detected using light and electron microscopy. Young chickens were infected with treated sporulated oocysts to determine their effect on infectivity. After 7 days pi, the percentage of excreted oocysts (oocyst shedding) was determined, and the chickens were slaughtered for histopathological examination of the cecal tissues. Under an electron microscope, allicin at a concentration of 180 mg/mL and alcoholic garlic extract at a concentration of 360 mg/mL demonstrate a high oocysticidal activity with severe destruction of the oocyst wall and the appearance of pores. In addition, both concentrations directly affected the infectivity of sporulated oocysts by reducing the shedding of oocysts and the pathological lesions of infected young chickens. We concluded that the ability of Allicin and alcoholic garlic extract to eliminate Eimeria oocysts makes them superior to chemical disinfectants as a disinfectant.

5.
Biomed Pharmacother ; 156: 113811, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36242843

RESUMEN

The use of apitherapy and natural herbal medicines for combating toxoplasmosis has garnered major attention from many researchers. However, there is no available information regarding the potential use of a combination of propolis and wheat germ oil (WGO) in the treatment of toxoplasmosis. In the present study, the potential effects of propolis, WGO, and their combination in the treatment of chronic toxoplasmosis in Swiss albino mice were investigated. Following induction of chronic toxoplasmosis, the potential antiparasitic effects of these substances were evaluated by parasitological assessment and by counting of Toxoplasma cysts. Additionally, the effects of the treatments on parasite loads were analyzed using TaqMan real-time quantitative PCR targeting the Toxoplasma P29 gene followed by investigation of the major histopathological changes in the brain, uterus, and kidney. Interestingly, the combination of propolis and WGO significantly (P ≤ 0.05) decreased the parasite burden in experimental animals compared with burdens seen in groups treated with propolis or WGO alone. Furthermore, the quantification of the DNA concentrations of Toxoplasma P29 gene after the treatment with propolis and WGO revealed a reduction in parasite load in treated groups versus the control group (infected untreated animals). Importantly, the severity of histopathological lesions was significantly (P ≤ 0.05) improved following treatment with propolis and WGO. Collectively, the present study indicated a potential novel role for propolis and WGO as an active apitherapy and natural herbal medication for treating chronic toxoplasmosis, combat the disease, and which could also help overcome the side effects of chemical drugs.


Asunto(s)
Própolis , Toxoplasma , Toxoplasmosis , Femenino , Animales , Ratones , Própolis/farmacología , Própolis/uso terapéutico , Aceites de Plantas/farmacología , Aceites de Plantas/uso terapéutico
6.
Front Vet Sci ; 9: 899854, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35782567

RESUMEN

Details about the epidemiological patterns and real contributions of different reservoir animals in maintaining the transmission cycle of Cryptosporidium spp. in Upper Egypt remain lacking. This study was designed to investigate the occurrence of Cryptosporidium spp. in cattle and buffalo (n = 608) from Upper Egypt. The parasite for the resulting positive samples by fecal examination was molecularly identified using nested PCR targeting the small subunit rRNA. Moreover, several explanatory variables, including animals' age, sex, condition, seasonal variations, were examined to describe the epidemiological pattern of the disease. Interestingly, the fecal examination revealed that 33.55% (204/608) of the animals under study were infected with Cryptosporidium, including 38.27% among cattle and 28.16% among buffalo. The parasite was molecularly identified using nested PCR, and their amplicons were identified in almost all fecal samples using microscopy (202/204). According to age as an individual variable factor, the infection rates of Cryptosporidium spp. in cattle calves with ages of <1, 1-3, and >3 months were 39.13, 34.04, and 54.54%, respectively. Meanwhile, in buffalo calves, the occurrence rates were 28.57, 27.27, and 29.41%, respectively. Regarding sex, female cattle calves were more susceptible to Cryptosporidium infection (51.28%) than males (26.19%) (p < 0.05), whereas male buffalo calves had a higher infection rate (32.25%) than females (25%). According to seasonal variations, the infection rates of Cryptosporidium spp. in cattle calves during spring, summer, autumn, and winter were 42.11, 30.43, 30, and 52.63%, respectively. In contrast, lower infection rates of 30, 21.42, 23.52, and 35% were reported in buffalo calves during spring, summer, autumn, and winter, respectively. The rate of infection was 45.16% in diarrheic cattle calves and 15.78% in non-diarrheic ones (p < 0.05). Meanwhile, the infection rate was 33.96% in diarrheic buffalo calves and 11.11% in non-diarrheic ones (p < 0.05). This study reported a higher occurrence of Cryptosporidium infection among the animals under study and revealed that buffalos and cattle can contribute to maintaining the transmission cycle of this zoonotic parasite in Upper Egypt.

7.
Biomed Pharmacother ; 139: 111671, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33957562

RESUMEN

Leishmaniasis, a neglected parasitic disease caused by a unicellular protozoan of the genus Leishmania, is transmitted through the bite of a female sandfly. The disease remains a major public health problem and is linked to tropical and subtropical regions, with an endemic picture in several regions, including East Africa, the Mediterranean basin and South America. The different causative species display a diversity of clinical presentations; therefore, the immunological data on leishmaniasis are both scarce and controversial for the different forms and infecting species of the parasite. The present review highlights the main immune parameters associated with leishmaniasis that might contribute to a better understanding of the pathogenicity of the parasite and the clinical outcomes of the disease. Our aim was to provide a concise overview of the immunobiology of the disease and the factors that influence it, as this knowledge may be helpful in developing novel chemotherapeutic and vaccine strategies.


Asunto(s)
Leishmania/inmunología , Leishmaniasis/inmunología , Leishmaniasis/terapia , Animales , Humanos , Inmunidad , Inmunoterapia , Leishmaniasis/parasitología , Psychodidae
8.
Vet Sci ; 8(2)2021 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-33672776

RESUMEN

Neglected parasitic diseases affect millions of people worldwide, resulting in high morbidity and mortality. Among other parasitic diseases, leishmaniasis remains an important public health problem caused by the protozoa of the genus Leishmania, transmitted by the bite of the female sand fly. The disease has also been linked to tropical and subtropical regions, in addition to being an endemic disease in many areas around the world, including the Mediterranean basin and South America. Although recent years have witnessed marked advances in Leishmania-related research in various directions, many issues have yet to be elucidated. The intention of the present review is to give an overview of the major virulence factors contributing to the pathogenicity of the parasite. We aimed to provide a concise picture of the factors influencing the reaction of the parasite in its host that might help to develop novel chemotherapeutic and vaccine strategies.

9.
Front Vet Sci ; 8: 754991, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35071376

RESUMEN

Avian coccidiosis is one of the major parasitic diseases in the poultry industry. The infection is caused by Eimeria species, and its treatment relies mainly on the administration of anticoccidial drugs, which can result in drug resistance and side effects. The recent trends in avian coccidiosis treatment is directed to the development of a new therapy using herbal compounds. S-Methylcysteine (SMC) is considered one of the organosulfur compounds in garlic that showed promising activity in the treatment of different pathological conditions via a wide range of anti-inflammatory and antioxidant mechanisms. In this study, the anticoccidial activity of SMC was investigated in Eimeria tenella-infected chickens compared to diclazuril as a widely used anticoccidial drug. In this regard, 14-day-old broilers were divided into six groups (n = 18). The first group (G1) was the healthy control group, while the second group (G2) was the non-infected SMC group treated at a dose of 50 mg/kg b.w. (high dose). Moreover, the third group (G3) was the positive control group (infected and non-treated). The fourth group (G4) was the infected group treated with SMC of 25 mg/kg b.w. (low dose), while the fifth group (G5) was the infected group treated with SMC of 50 mg/kg b.w. (high dose). Conversely, the sixth group (G6) was the diclazuril-treated group. The anticoccidial effects of SMC and diclazuril were evaluated by counting oocysts and recording the body weight gain, feed conversion ratio, clinical signs, lesions, and mortality rate. Interestingly, SMC showed potent anticoccidial activity, which was exemplified by reduction of oocyst count. Furthermore, the biochemical, antioxidant, and anti-inflammatory parameters in the cecal tissues were restored toward their control levels in G4, G5, and G6. Histopathological observation of cecal tissues was consistent with the aforementioned results revealing the ameliorative effect of SMC against E. tenella infection. This study concluded novel findings in relation to the anticoccidial role of SMC as a plant-based compound against the E. tenella-induced coccidiosis in broiler chickens combined with its antioxidative and anti-inflammatory properties. Further studies for exploring the mechanistic pathways involved in this activity and the potential benefits from its use in association with conventional anticoccidial drugs are warranted.

10.
Braz. J. Pharm. Sci. (Online) ; 57: e18997, 2021. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1345455

RESUMEN

In the present study a series of 34 synthetic ligustrazine-containing α, ß-Unsaturated carbonyl-based compounds and oximes, recognized as anticancer compounds were assessed against protozoa of the Trypanosoma and Leishmania species. Ligustrazine, chemically known as tetramethylpyrazine (TMP), was selected as the core moiety for the synthesis of α, ß-Unsaturated carbonyl-based compounds and these compounds were selected as precursors for the synthesis of new oximes. Some derivates, including 5f and 6i, showed multiple activities against all tested strains. In particular compounds 5f and 8o are the most potent and they are, therefore, potential candidates for trypanosomiasis and leishmaniasis


Asunto(s)
Oximas/agonistas , Ciclohexanonas/agonistas , Trypanosoma/clasificación , Tripanosomiasis , Leishmaniasis , Leishmania/clasificación
11.
Eur J Med Chem ; 207: 112745, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32877804

RESUMEN

Herein we describe design and synthesis of different series of novel small molecules featuring 3-methylthiazolo[3,2-a]benzimidazole moiety (as a tail) connected to the zinc anchoring benzenesulfonamide moiety via ureido (7), enaminone (12), hydrazone (14), or hydrazide (15) linkers. The newly prepared conjugates have been screened for their inhibitory activities toward four human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms: hCA I, II, IX and XII. Thereafter, the urea and enaminone linkers were elongated by one- or two-atoms spacers to afford the elongated counterparts 9 and 13, respectively. Finally, the zinc anchoring sulfonamide group was replaced by the carboxylic acid group to afford acids 17. Compounds 12d, 13b and 15 displayed single-digit nanomolar CA IX inhibitory activities (KIs = 6.2, 9.7 and 5.5 nM, respectively), along with good selectivity towards hCA IX over hCA I and II. Subsequently, they were screened for their growth inhibitory actions against breast cancer MCF-7 and MDA-MB-231 cell lines, and for their impact on cell cycle progression and induction of apoptosis. Moreover, a molecular docking study was conducted to gain insights for the plausible binding interactions of target sulfonamides within hCA isoforms II, IX and XII binding sites.


Asunto(s)
Bencimidazoles/química , Bencimidazoles/farmacología , Anhidrasas Carbónicas/metabolismo , Diseño de Fármacos , Modelos Moleculares , Sulfonamidas/química , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Bencimidazoles/síntesis química , Inhibidores de Anhidrasa Carbónica/síntesis química , Inhibidores de Anhidrasa Carbónica/química , Inhibidores de Anhidrasa Carbónica/farmacología , Anhidrasas Carbónicas/química , Dominio Catalítico , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Humanos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/química , Isoenzimas/metabolismo , Células MCF-7 , Bencenosulfonamidas
12.
Int J Parasitol Drugs Drug Resist ; 6(1): 23-34, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27054061

RESUMEN

Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH) was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1) was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect) forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei, bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial FoF1 ATPase.


Asunto(s)
Mitocondrias/efectos de los fármacos , Compuestos Organofosforados/farmacología , ATPasas de Translocación de Protón/metabolismo , Tripanocidas/farmacología , Trypanosoma brucei brucei/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Azidas/farmacología , Calcio/metabolismo , Línea Celular , ADN Mitocondrial/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/genética , Mitocondrias/metabolismo , Compuestos Organofosforados/química , Interferencia de ARN , Succinato Deshidrogenasa/metabolismo , Trypanosoma brucei brucei/citología , Trypanosoma brucei brucei/crecimiento & desarrollo , Tripanosomiasis Africana/parasitología
13.
Antimicrob Agents Chemother ; 59(11): 6708-16, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26282430

RESUMEN

The human and veterinary disease complex known as African trypanosomiasis continues to inflict significant global morbidity, mortality, and economic hardship. Drug resistance and toxic side effects of old drugs call for novel and unorthodox strategies for new and safe treatment options. We designed methyltriazenyl purine prodrugs to be rapidly and selectively internalized by the parasite, after which they disintegrate into a nontoxic and naturally occurring purine nucleobase, a simple triazene-stabilizing group, and the active toxin: a methyldiazonium cation capable of damaging DNA by alkylation. We identified 2-(3-acetyl-3-methyltriazen-1-yl)-6-hydroxypurine (compound 1) as a new lead compound, which showed submicromolar potency against Trypanosoma brucei, with a selectivity index of >500, and it demonstrated a curative effect in animal models of acute trypanosomiasis. We investigated the mechanism of action of this lead compound and showed that this molecule has significantly higher affinity for parasites over mammalian nucleobase transporters, and it does not show cross-resistance with current first-line drugs. Once selectively accumulated inside the parasite, the prodrug releases a DNA-damaging methyldiazonium cation. We propose that ensuing futile cycles of attempted mismatch repair then lead to G2/M phase arrest and eventually cell death, as evidenced by the reduced efficacy of this purine analog against a mismatch repair-deficient (MSH2(-/-)) trypanosome cell line. The observed absence of genotoxicity, hepatotoxicity, and cytotoxicity against mammalian cells revitalizes the idea of pursuing parasite-selective DNA alkylators as a safe chemotherapeutic option for the treatment of human and animal trypanosomiasis.


Asunto(s)
ADN Protozoario/genética , Purinas/química , Purinas/uso terapéutico , Tripanocidas/química , Tripanocidas/uso terapéutico , Tripanosomiasis Africana/tratamiento farmacológico , Animales , Línea Celular , ADN Protozoario/efectos de los fármacos , Femenino , Ratones , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/patogenicidad , Tripanosomiasis Africana/parasitología
14.
Mol Microbiol ; 96(4): 887-900, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25708978

RESUMEN

The Trypanosoma brucei aminopurine transporter P2/TbAT1 has long been implicated in the transport of, and resistance to, the diamidine and melaminophenyl arsenical classes of drugs that form the backbone of the pharmacopoeia against African trypanosomiasis. Genetic alterations including deletions and single nucleotide polymorphisms (SNPs) have been observed in numerous strains and clinical isolates. Here, we systematically investigate each reported mutation and assess their effects on transporter function after expression in a tbat1(-/-) T. brucei line. Out of a set of six reported SNPs from a reported 'resistance allele', none significantly impaired sensitivity to pentamidine, diminazene or melarsoprol, relative to the TbAT1-WT allele, although several combinations, and the deletion of the codon for residue F316, resulted in highly significant impairment. These combinations of SNPs, and ΔF316, also strongly impaired the uptake of [(3)H]-adenosine and [(3)H]-diminazene, identical to the tbat1(-/-) control. The TbAT1 protein model predicted that residues F19, D140 and F316 interact with the substrate of the transporter. Mutation of D140 to alanine resulted in an inactive transporter, whereas the mutation F19A produced a transporter with a slightly increased affinity for [(3)H]-diminazene but reduced the uptake rate. The results presented here validate earlier hypotheses of drug binding motifs for TbAT1.


Asunto(s)
Modelos Moleculares , Proteínas de Transporte de Nucleósidos/química , Proteínas de Transporte de Nucleósidos/genética , Tripanocidas/farmacología , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma brucei brucei/genética , Alelos , Diminazeno/farmacología , Resistencia a Múltiples Medicamentos/genética , Cinética , Melarsoprol/farmacología , Mutación , Proteínas de Transporte de Nucleósidos/metabolismo , Pruebas de Sensibilidad Parasitaria , Pentamidina/farmacología , Polimorfismo de Nucleótido Simple , Dominios y Motivos de Interacción de Proteínas , Trypanosoma brucei brucei/química
15.
ACS Med Chem Lett ; 6(2): 151-5, 2015 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-25699142

RESUMEN

In previous studies, we have shown that phosphonium salt diphenyl derivatives are attractive antitrypanosomal hit compounds with EC50 values against Trypanosoma brucei in the nanomolar range. To evaluate the role of the cationic center on the trypanocidal activity and extend the structure-activity relationship (SAR) of this series, trialkylammonium, pyridinium, and quinolinium salt analogues were synthesized and evaluated in vitro against T. b. brucei. Similar SARs were observed with ammonium and phosphonium salts showing that charge dispersion and lipophilic groups around the cationic center are crucial to obtain submicromolar activities. The new compounds were equally effective against wild type (T. b. brucei s427) and resistant strains (TbAT1-KO and TbB48) of trypanosomes indicating that the P2 and high affinity pentamidine transporters (HAPT) are not essential to their trypanocidal action. Similarly to phosphonium salt derivatives, diffusion seems to be the main route of entry into trypanosomes.

16.
Mol Pharmacol ; 87(3): 451-64, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25527638

RESUMEN

We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei. However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014-resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014-exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ-glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.


Asunto(s)
Curcumina/análogos & derivados , Curcumina/metabolismo , Glutatión/análogos & derivados , Espermidina/análogos & derivados , Tripanocidas/metabolismo , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma brucei brucei/metabolismo , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Curcumina/farmacología , Glutatión/metabolismo , Humanos , Espermidina/metabolismo , Tripanocidas/farmacología
17.
J Med Chem ; 55(6): 2606-22, 2012 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-22390399

RESUMEN

A series of 73 bisphosphonium salts and 10 monophosphonium salt derivatives were synthesized and tested in vitro against several wild type and resistant lines of Trypanosoma brucei (T. b. rhodesiense STIB900, T. b. brucei strain 427, TbAT1-KO, and TbB48). More than half of the compounds tested showed a submicromolar EC(50) against these parasites. The compounds did not display any cross-resistance to existing diamidine therapies, such as pentamidine. In most cases, the compounds displayed a good selectivity index versus human cell lines. None of the known T. b. brucei drug transporters were required for trypanocidal activity, although some of the bisphosphonium compounds inhibited the low affinity pentamidine transporter. It was found that phosphonium drugs act slowly to clear a trypanosome population but that only a short exposure time is needed for irreversible damage to the cells. A comparative molecular field analysis model (CoMFA) was generated to gain insights into the SAR of this class of compounds, identifying key features for trypanocidal activity.


Asunto(s)
Compuestos Organofosforados/síntesis química , Tripanocidas/síntesis química , Trypanosoma brucei brucei/efectos de los fármacos , Trypanosoma brucei rhodesiense/efectos de los fármacos , Proteínas Portadoras/metabolismo , Línea Celular , Resistencia a Medicamentos , Humanos , Modelos Moleculares , Proteínas de Transporte de Nucleósidos/metabolismo , Compuestos Organofosforados/química , Compuestos Organofosforados/farmacología , Pentamidina/metabolismo , Relación Estructura-Actividad Cuantitativa , Tripanocidas/química , Tripanocidas/farmacología
18.
J Antimicrob Chemother ; 66(1): 111-25, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21078603

RESUMEN

OBJECTIVES: to investigate the anti-kinetoplastid activity of choline-derived analogues with previously reported antimalarial efficacy. METHODS: from an existing choline analogue library, seven antimalarial compounds, representative of the first-, second- and third-generation analogues previously developed, were assessed for activity against Trypanosoma and Leishmania spp. Using a variety of techniques, the effects of choline analogue exposure on the parasites were documented and a preliminary investigation of their mode of action was performed. RESULTS: the activities of choline-derived compounds against Trypanosoma brucei and Leishmania mexicana were determined. The compounds displayed promising anti-kinetoplastid activity, particularly against T. brucei, to which 4/7 displayed submicromolar EC(50) values for the wild-type strain. Low micromolar concentrations of most compounds cleared trypanosome cultures within 24-48 h. The compounds inhibit a choline transporter in Leishmania, but their entry may not depend only on this carrier; T. b. brucei lacks a choline carrier and the mode of uptake remains unclear. The compounds had no effect on the overall lipid composition of the cells, cell cycle progression or cyclic adenosine monophosphate production or short-term effects on intracellular calcium levels. However, several of the compounds, displayed pronounced effects on the mitochondrial membrane potential; this action was not associated with production of reactive oxygen species but rather with a slow rise of intracellular calcium levels and DNA fragmentation. CONCLUSIONS: the choline analogues displayed strong activity against kinetoplastid parasites, particularly against T. b. brucei. In contrast to their antimalarial activity, they did not act on trypanosomes by disrupting choline salvage or phospholipid metabolism, instead disrupting mitochondrial function, leading to chromosomal fragmentation.


Asunto(s)
Antiprotozoarios/farmacología , Cationes Bivalentes/farmacología , Colina/análogos & derivados , Colina/farmacología , Leishmania mexicana/efectos de los fármacos , Trypanosoma brucei brucei/efectos de los fármacos , Antiprotozoarios/química , Fragmentación del ADN , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/efectos de los fármacos
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