Toxoplasma gondii is the causative agent of toxoplasmosis with symptoms of congenital neurological and ocular diseases and acquired lymphadenitis, retinochoroiditis, and meningoencephalitis. Small molecules which block the activity of protein kinases were tested in in vitro culture of T. gondii to find new therapeutic drugs of safer and more effective than the combined administration of pyrimethamine and sulfadoxine that sometimes provoke lethal Stevens-Johnson syndrome. Among them, Gefitinib and Crizotinib inhibited intracellular growth of T. gondii in HeLa cells by counting the number of T. gondii per parasitophorous vacuolar membrane whereas Sunitinib did not. Gefitinib inhibited the growth of T. gondii in a dose-dependent manner over 5 microM up to the tolerable concentration of HeLa cells and halted the division of the parasite immediately from the time point of treatment. Gefitinib inhibition suggests that tyrosine kinases of EGFR family or other homologous kinases of the parasite itself may be the target to cause the block of T. gondii growth.
Antiprotozoal Agents/*pharmacology ; Dose-Response Relationship, Drug ; Drug Repositioning ; HeLa Cells ; Humans ; Parasitic Sensitivity Tests ; Quinazolines/*pharmacology ; Toxoplasma/*drug effects/*growth & development

Leishmaniasis is a neglected disease and endemic in developing countries. A lack of adequate and definitive chemotherapeutic agents to fight against this infection has led to the investigation of numerous compounds. The aim of this study was to investigate the effect of RT-01, an organotellurane compound presenting biological activities, in 2 experimental systems against Leishmania amazonensis. The in vitro system consisted of promastigotes and amastigotes forms of the parasite, and the in vivo system consisted of L. amazonensis infected BALB/c mice, an extremely susceptible mouse strain. The compound proved to be toxic against promastigotes and amastigotes. The study also showed that treatment with RT-01 produces an effect similar to that treatment with the reference antimonial drug, Glucantime, in L. amazonensis infected mice. The best results were obtained following RT-01 intralesional administration (720 microgram/kg/day); mice showed significant delay in the development of cutaneous lesions and decreased numbers of parasites obtained from the lesions. Significant differences in tissue pathology consisted mainly of no expressive accumulation of inflammatory cells and well-preserved structures in the skin tissue of RT-01-treated mice compared with expressive infiltration of infected cells replacing the skin tissue in lesions of untreated mice. These findings highlight the fact that the apparent potency of organotellurane compounds, together with their relatively simple structure, may represent a new avenue for the development of novel drugs to combat parasitic diseases.
Animals ; Antiprotozoal Agents/*pharmacology ; Disease Models, Animal ; Female ; Humans ; Leishmania mexicana/*drug effects ; Leishmaniasis/drug therapy/*parasitology ; Mice ; Mice, Inbred BALB C ; Organometallic Compounds/*pharmacology

Leishmaniasis is a neglected disease and endemic in developing countries. A lack of adequate and definitive chemotherapeutic agents to fight against this infection has led to the investigation of numerous compounds. The aim of this study was to investigate the effect of RT-01, an organotellurane compound presenting biological activities, in 2 experimental systems against Leishmania amazonensis. The in vitro system consisted of promastigotes and amastigotes forms of the parasite, and the in vivo system consisted of L. amazonensis infected BALB/c mice, an extremely susceptible mouse strain. The compound proved to be toxic against promastigotes and amastigotes. The study also showed that treatment with RT-01 produces an effect similar to that treatment with the reference antimonial drug, Glucantime, in L. amazonensis infected mice. The best results were obtained following RT-01 intralesional administration (720 microgram/kg/day); mice showed significant delay in the development of cutaneous lesions and decreased numbers of parasites obtained from the lesions. Significant differences in tissue pathology consisted mainly of no expressive accumulation of inflammatory cells and well-preserved structures in the skin tissue of RT-01-treated mice compared with expressive infiltration of infected cells replacing the skin tissue in lesions of untreated mice. These findings highlight the fact that the apparent potency of organotellurane compounds, together with their relatively simple structure, may represent a new avenue for the development of novel drugs to combat parasitic diseases.
Animals ; Antiprotozoal Agents/*pharmacology ; Disease Models, Animal ; Female ; Humans ; Leishmania mexicana/*drug effects ; Leishmaniasis/drug therapy/*parasitology ; Mice ; Mice, Inbred BALB C ; Organometallic Compounds/*pharmacology

Leishmaniasis, a neglected disease caused by Leishmania protozoans, primarily affects people in tropical and subtropical areas. Chemotherapy based on the use of pentavalent antimonials, amphotericin B, paromomycin, miltefosine and liposomal amphotericin B is currently the only effective treatment. However, adverse effects, long-term treatment and the emergence of parasite resistance have led to the search for alternative treatments. Natural products used in traditional medicine provide an unlimited source of molecules for the identification of new drugs, and the Amazon region has abundant biodiversity that includes several species of plants and animals, providing a rich source of new products and compounds. Although the literature describes numerous promising compounds and extracts for combating Leishmania protozoans, the results of such research have not been embraced by the pharmaceutical industry for the development of new drugs. Therefore, this review focused on the antileishmanial activity of extracts, isolated compounds and essential oils commonly used by the local population in the Brazilian Amazonian region to treat several illnesses and described in the literature as promising compounds for combating leishmaniasis.
Animals ; Antiprotozoal Agents ; chemistry ; isolation & purification ; pharmacology ; Brazil ; Humans ; Leishmania ; drug effects ; genetics ; growth & development ; Leishmaniasis ; drug therapy ; parasitology ; Plant Extracts ; chemistry ; isolation & purification ; pharmacology ; Plants, Medicinal ; chemistry

Our previous study demonstrated that BM-cyclin 1, a traditional anti-mycoplasma drug, could effectively reverse the multidrug resistance (MDR) of C-A120 cells. The present study aims to explore the reversal effect of BM-cyclin 1 on MDR and its mechanisms in BALB/C nude mice bearing C-A120 cells. Immunoblotting analysis and reverse transcription-polymerase chain reaction (RT-PCR) were used to study the change in multidrug resistance-associated protein 2 (MRP2) induced by BM-cyclin 1. We found that the expression levels of MRP2 protein and mRNA in C-A120 cells treated with BM-cyclin 1 were reduced significantly. Chemical colorimetry revealed no significant change in the level of glutathione (GSH). In the xenograft model, the inhibitory rate of C-A120 cells growth in BM-cyclin 1 plus adriamycin (ADM) group was 52%, which was significantly higher than in control group (P<0.01). The immunoblotting and RT-PCR results conclusively demonstrated that BM-cycin 1 could significantly reduce the expression of MRP2 in transplanted tumor. In conclusion, BM-cyclin 1 could effectively reverse the MDR of C-A120 cells in vivo by suppressing the expression of MRP2.
Animals ; Antiprotozoal Agents ; pharmacology ; Cell Line, Tumor ; Diterpenes ; pharmacology ; Down-Regulation ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Humans ; Mice ; Mice, Nude ; Minocycline ; pharmacology ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Xenograft Model Antitumor Assays

One of the most common drugs used against a wide variety of anaerobic protozoan parasites is metronidazole. However, this drug is mutagenic for bacteria and is a potent carcinogen for rodents. Thymus vulgaris is used for cough suppression and relief of dyspepsia. Also it has antibacterial and antifungal properties. The aim of this study was to investigate antiamebic effect of Thymus vulgaris against Entamoeba histolytica in comparison with metronidazole. One hundred gram air-dried T. vulgaris plant was obtained and macerated at 25 degrees C for 14 days using n-hexane and a mixture of ethanol and water. For essential oil isolation T. vulgaris was subjected to hydrodistillation using a clevenger-type apparatus for 3 hr. E. histolytica, HM-1: IMSS strain was used in all experiments. It was found that the minimal inhibitory concentration (MIC) for T. vulgaris hydroalcoholic, hexanic extracts, and the essential oil after 24 hr was 4 mg/mL, 4 mg/mL, and 0.7 mg/mL, respectively. After 48 hr the MIC for T. vulgaris hydroalcoholic and hexanic extracts was 3 and 3 mg/mL, respectively. Therefore, it can be concluded that the Iranian T. vulgaris is effective against the trophozoites of E. histolytica.
Animals ; Antiprotozoal Agents/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Entamoeba histolytica/*drug effects ; Iran ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/*pharmacology ; Plant Oils/chemistry/pharmacology ; Thymus Plant/*chemistry

The disinfectant effects (DEs) of 10 types of chemicals, defined by their ability to destroy or inhibit oocysts and consequently prevent sporulation of Eimeria tenella field isolate, were evaluated in vitro. Correct species assignments and sample purities were confirmed by the singular internal transcribed spacer (ITS)-PCR analysis. A total of 18 treatments were performed, and the disinfection suppression levels were 75.9% for 39% benzene + 22% xylene (1:10 dilution), 85.5% for 30% cresol soup (1:1 dilution), and 91.7% for 99.9% acetic acid (1:2 dilution) group. The results indicate that acetic acid, cresol soup, and benzene+xylene are good candidates for suppression of E. tenella oocyst sporulation.
Animals ; Antiprotozoal Agents/*pharmacology ; Cluster Analysis ; DNA, Protozoan/chemistry/genetics ; DNA, Ribosomal Spacer/chemistry/genetics ; Disinfectants/*pharmacology ; Eimeria tenella/*drug effects/*growth & development ; Microscopy ; Molecular Sequence Data ; Parasitic Sensitivity Tests ; Phylogeny ; Sequence Analysis, DNA ; Spores, Protozoan/*drug effects/*growth & development

Tamoxifen is an antagonist of the estrogen receptor and currently used for the treatment of breast cancer. The current treatment of cutaneous leishmaniasis with pentavalent antimony compounds is not satisfactory. Therefore, in this study, due to its antileishmanial activity, effects of tamoxifen on the growth of promastigotes and amastigotes of Leishmania major Iranian strain were evaluated in vitro. Promastigotes and amastigotes were treated with different concentrations (1, 5, 10, 20, and 50 µg/ml) and time periods (24, 48, and 72 hr) of tamoxifen. After tamoxifen treatment, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5 biphenyl tetrazolium bromide assay) was used to determine the percentage of live parasites and Graph Pad Prism software to calculate IC50. Flow cytometry was applied to investigate the induction of tamoxifen-induced apoptosis in promastigotes. The half maximal inhibitory concentration (IC50) of tamoxifen on promastigotes was 2.6 µg/ml after 24 hr treatment. Flow cytometry analysis showed that tamoxifen induced early and late apoptosis in Leishmania promastigotes. While after 48 hr in control group the apoptosis was 2.0%, the 50 µg/L concentration of tamoxifen increased it to 59.7%. Based on the in vitro antileishmanial effect, tamoxifen might be used for leishmaniasis treatment; however, further researches on in vivo effects of tamoxifen in animal models are needed.
Animals ; Antiprotozoal Agents/pharmacology/therapeutic use ; Apoptosis/*drug effects ; Cells, Cultured ; Inhibitory Concentration 50 ; Leishmania major/*drug effects ; Leishmaniasis, Cutaneous/drug therapy ; Macrophages/parasitology ; Mice ; Tamoxifen/*pharmacology/therapeutic use

Leishmaniasis is a worldwide uncontrolled parasitic disease due to the lack of effective drug and vaccine. To speed up effective drug development, we need powerful methods to rapidly assess drug effectiveness against the intracellular form of Leishmania in high throughput assays. Reporter gene technology has proven to be an excellent tool for drug screening in vitro. The effects of reporter proteins on parasite infectivity should be identified both in vitro and in vivo. In this research, we initially compared the infectivity rate of recombinant Leishmania major expressing stably enhanced green fluorescent protein (EGFP) alone or EGFP-luciferase (EGFP-LUC) with the wild-type strain. Next, we evaluated the sensitivity of these parasites to amphotericin B (AmB) as a standard drug in 2 parasitic phases, promastigote and amastigote. This comparison was made by MTT and nitric oxide (NO) assay and by quantifying the specific signals derived from reporter genes like EGFP intensity and luciferase activity. To study the amastigote form, both B10R and THP-1 macrophage cell lines were infected in the stationary phase and were exposed to AmB at different time points. Our results clearly revealed that the 3 parasite lines had similar in vitro infectivity rates with comparable parasite-induced levels of NO following interferon-gamma/lipopolysaccharide induction. Based on our results we proposed the more reporter gene, the faster and more sensitive evaluation of the drug efficiency.
Amphotericin B/*pharmacology ; Animals ; Antiprotozoal Agents/*pharmacology ; Drug Evaluation, Preclinical/instrumentation/*methods ; Female ; Gene Expression ; Genes, Reporter ; Green Fluorescent Proteins/genetics/*metabolism ; Humans ; Leishmania major/*drug effects/genetics/growth & development/physiology ; Leishmaniasis, Cutaneous/*parasitology ; Luciferases/genetics/*metabolism ; Mice

Babesia gibsoni is an intraerythrocytic apicomplexan parasite that causes piroplasmosis in dogs. B. gibsoni infection is characterized clinically by fever, regenerative anemia, splenomegaly, and sometimes death. Since no vaccine is available, rapid and accurate diagnosis and prompt treatment of infected animals are required to control this disease. Over the past decade, several candidate molecules have been identified using biomolecular techniques in the authors' laboratory for the development of a serodiagnostic method, vaccine, and drug for B. gibsoni. This review article describes newly identified candidate molecules and their applications for diagnosis, vaccine production, and drug development of B. gibsoni.
Animals ; Antigens, Protozoan/*diagnostic use/*immunology ; Antiprotozoal Agents/*isolation & purification/pharmacology ; Babesia/*drug effects/immunology/*isolation & purification ; Babesiosis/*diagnosis/drug therapy/prevention & control ; Dogs ; Drug Discovery/methods ; Protozoan Vaccines/*immunology