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

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

Visceral leishmaniasis (VL) or kala-azar mainly affects children in endemic areas. This study was conducted to determine the seroprevalence of VL using direct agglutination test (DAT) in children living in rural districts of Alborz Province located 30 km from Tehran capital city of Iran. Multi-stage cluster random sampling was applied. Blood samples were randomly collected from 1,007 children under 10 years of age in the clusters. A total of 37 (3.7%) of the studied population showed anti-Leishmania infantum antibodies with titers of > or =1:800. There was a significant association between positive sera and various parts of the rural areas of Alborz Province (P<0.002). Two children with anti-Leishmania infantum antibodies titers of > or =1:3,200 indicated kala-azar clinical features and treated with anti-leishmaniasis drugs in pediatric hospital. The findings of this study indicated that Leishmania infection is prevalent in rural areas of Alborz Province. Therefore, it is necessary to increase the awareness and alertness among physicians and public health managers, particularly in high-risk rural areas of the province in Iran.
Antibodies, Protozoan/blood ; Child ; Child, Preschool ; Female ; Health Policy ; Humans ; Iran/epidemiology ; Leishmania infantum/immunology/isolation & purification/physiology ; Leishmaniasis, Visceral/blood/*epidemiology/parasitology ; Male ; *Rural Health ; Seroepidemiologic Studies

Visceral leishmaniasis or kala-azar is an endemic parasitic disease in some parts of the world which is characterized by fever, splenomegaly, and pancytopenia in most of the cases. Herein we report an 11 month-old male infant with diagnosis of kala-azar who presented with pallor, hepatosplenomegaly, failure to gain weight, and no history of fever. Surprisingly, fever started after beginning of meglumine antimoniate treatment in this patient. As far as we are aware of, this is a rare presentation of visceral leishmaniasis. Therefore, clinicians especially in endemic areas are highly recommended to include kala-azar among differential diagnosis of unexplained anemia without fever to prevent misdiagnosis of this potentially fatal, but treatable condition.
Amphotericin B/therapeutic use ; Anemia/*diagnosis/parasitology ; Antiprotozoal Agents/*therapeutic use ; Deoxycholic Acid/therapeutic use ; Diagnosis, Differential ; Drug Combinations ; Endemic Diseases ; *Fever ; Humans ; Infant ; Iran ; Leishmania infantum/pathogenicity ; Leishmaniasis, Visceral/*diagnosis/*drug therapy/parasitology ; Male ; Meglumine/therapeutic use ; Organometallic Compounds/therapeutic use ; Splenomegaly/parasitology

AIM: The anti-leishmanial activity of methanolic extracts of Calendula officinalis flowers, Datura stramonium seeds, and Salvia officinalis leaves against extracellular (promastigote) and intracellular (amastigote) forms of Leishmania major were evaluated in this study. METHOD: In the first stage, promastigote forms of L. major, were treated with different doses of the plant extracts in a 96-well tissue-culture microplate and IC50 values for each extract were measured with colorimetric MTT assay. In the second stage, macrophage cells were infected with L. major promastigotes. Infected macrophages were treated with plant extracts. Then the macrophages were stained with Gimsa and the number of infected macrophages and amastigotes were counted with a light microscope. RESULTS: The results indicated that the plant extracts inhibited the growth of promastigotes and amastigotes of L. major. Inhibitory concentrations (IC50) for promastigote assay were 108.19, 155.15, and 184.32 μgmL(-1) for C. officinalis flowers, D. stramonium seeds and S. officinalis, respectively. The extracts also reduced the number of amastigotes in macrophage cells from 264 for control group to 88, 97, and 102 for test groups. Although the anti-leishmanial activity of the extracts were not comparable with the standard drug, miltefosine; but they showed significant efficiency in reducing the number of amastigotes in macrophages, in comparison with the control group (P < 0.001). These plant extracts had lower toxicity compared with miltefosine. CONCLUSION This study demonstrates the potential efficacy of the methanolic extracts of C. officinalis flowers, D. stramonium seeds, and S. officinalis leaves to control of cutaneous leishmaniasis.
Antiparasitic Agents ; pharmacology ; therapeutic use ; Calendula ; Cell Line ; Datura stramonium ; Flowers ; In Vitro Techniques ; Leishmania major ; drug effects ; Leishmaniasis ; drug therapy ; parasitology ; Macrophages ; drug effects ; parasitology ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Plant Leaves ; Salvia officinalis ; Seeds

The mainstay therapy against leishmaniasis is still pentavalent antimonial drugs; however, the rate of antimony resistance is increasing in endemic regions such as Iran. Understanding the molecular basis of resistance to antimonials could be helpful to improve treatment strategies. This study aimed to recognize genes involved in antimony resistance of Leishmania tropica field isolates. Sensitive and resistant L. tropica parasites were isolated from anthroponotic cutaneous leishmaniasis patients and drug susceptibility of parasites to meglumine antimoniate (Glucantime(R)) was confirmed using in vitro assay. Then, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) and real-time reverse transcriptase-PCR (RT-PCR) approaches were utilized on mRNAs from resistant and sensitive L. tropica isolates. We identified 2 known genes, ubiquitin implicated in protein degradation and amino acid permease (AAP3) involved in arginine uptake. Also, we identified 1 gene encoding hypothetical protein. Real-time RT-PCR revealed a significant upregulation of ubiquitin (2.54-fold), and AAP3 (2.86-fold) (P<0.05) in a resistant isolate compared to a sensitive one. Our results suggest that overexpression of ubiquitin and AAP3 could potentially implicated in natural antimony resistance.
Amino Acid Transport Systems/*genetics/metabolism ; Antimony/*pharmacology ; Antipruritics/*pharmacology ; *Drug Resistance ; Humans ; Leishmania tropica/drug effects/enzymology/*genetics/isolation & purification ; Leishmaniasis, Cutaneous/*parasitology ; Protozoan Proteins/*genetics/metabolism ; Ubiquitin/*genetics/metabolism

Leishmania tropica is one of the causative agents of leishmaniasis in humans. Routes of infection have been reported to be an important variable for some species of Leishmania parasites. The role of this variable is not clear for L. tropica infection. The aim of this study was to explore the effects of route of L. tropica infection on the disease outcome and immunologic parameters in BALB/c mice. Two routes were used; subcutaneous in the footpad and intradermal in the ear. Mice were challenged by Leishmani major, after establishment of the L. tropica infection, to evaluate the level of protective immunity. Immune responses were assayed at week 1 and week 4 after challenge. The subcutaneous route in the footpad in comparison to the intradermal route in the ear induced significantly more protective immunity against L. major challenge, including higher delayed-type hypersensitivity responses, more rapid lesion resolution, lower parasite loads, and lower levels of IL-10. Our data showed that the route of infection in BALB/c model of L. tropica infection is an important variable and should be considered in developing an appropriate experimental model for L. tropica infections.
Animals ; Disease Models, Animal ; Female ; Leishmania major/*immunology ; Leishmania tropica/*immunology/*pathogenicity ; Leishmaniasis/*immunology/parasitology/*pathology ; Mice ; Mice, Inbred BALB C ; Treatment Outcome

Various Leishmania species were engineered with green fluorescent protein (GFP) using episomal vectors that encoded an antibiotic resistance gene, such as aminoglycoside geneticin sulphate (G418). Most reports of GFP-Leishmania have used the flagellated extracellular promastigote, the stage of parasite detected in the midgut of the sandfly vector; fewer studies have been performed with amastigotes, the stage of parasite detected in mammals. In this study, comparisons were made regarding the efficiency for in vitro G418 selection of GFP-Leishmania amazonensis promastigotes and amastigotes and the use of in vivo G418 selection. The GFP-promastigotes retained episomal plasmid for a prolonged period and G418 treatment was necessary and efficient for in vitro selection. In contrast, GFP-amastigotes showed low retention of the episomal plasmid in the absence of G418 selection and low sensitivity to antibiotics in vitro. The use of protocols for G418 selection using infected BALB/c mice also indicated low sensitivity to antibiotics against amastigotes in cutaneous lesions.
Amebicides/*pharmacology ; Animals ; Flow Cytometry ; Gentamicins/*pharmacology ; Green Fluorescent Proteins/*chemistry ; Host-Parasite Interactions ; Leishmania mexicana/drug effects/genetics/*growth & development ; Leishmaniasis, Cutaneous/*parasitology ; Luminescent Agents/*chemistry ; Macrophages, Peritoneal/parasitology ; Mice ; Mice, Inbred BALB C ; Organisms, Genetically Modified ; Spectrometry, Fluorescence

Leishmaniasis (Kala-azar) from different endemic regions of China expresses different clinic and epidemiological features, and traditionally is classified as hilly, plain and desert types/foci. We concentrated our review on whether the pathogens from those foci were different at molecular level, if so, whether there are were molecular markers readily identifiable by molecular technologies. This was a review of a 20-year search for such markers by using kinetoplastic DNA (kDNA), nDNA hybridization, PCR-SSCP, RAPD and sequence analysis of SSU rDNA variable regions and LACK gene. The results showed that heterogeneities at molecular level exist in Leishmania isolated from different foci of China, which could be used as markers for different types of Leishmaniasis in China.
China ; DNA Fingerprinting ; DNA, Protozoan ; analysis ; genetics ; Genotype ; Humans ; Leishmania donovani ; classification ; genetics ; isolation & purification ; Leishmaniasis, Visceral ; classification ; parasitology ; Mutation