Efficacy of biogenic selenium nanoparticles against Leishmania major: in vitro and in vivo studies.

PROJECT: This study investigated the in vitro and in vivo effectiveness of biogenic selenium nanoparticles (Se NPs), biosynthesized by Bacillus sp. MSh-1, against Leishmania major (MRHO/IR/75/ER). PROCEDURE: The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity effects of the biogenic Se NPs against both promastigote and amastigote forms of L. major. In a separate in vivo experiment, we also determined the preventive and therapeutic effects of biogenic Se NPs in BALB/c mice following subcutaneous infected with L. major. RESULTS: The MTT assays showed that the highest toxicity occurred after 72 h against both promastigote and amastigote forms of L. major. The cytotoxicity of Se NPs was higher at all incubation times (24, 48, and 72 h) against the promastigote than the amastigote form (p<0.05). The 50% inhibitory concentrations (IC50) of the Se NPs were 1.62±0.6 and 4.4±0.6 µg ml(-1) against the promastigote and amastigote forms, respectively, after a 72-h incubation period. Apoptosis assays showed DNA fragmentation in promastigotes treated with Se NPs. In an animal challenge, prophylactic doses of biogenic Se NPs delayed the development of localized cutaneous lesions. Moreover, daily administration of Se NPs (5 or 10 mg kg(-1) day(-1)) in similarly infected BALB/c mice that had not received prophylactic doses of Se NPs also abolished the localized lesions after 14 days. CONCLUSION: Based on these in vitro and in vivo studies, biogenic Se NPs can be considered as a novel therapeutic agent for treatment of the localized lesions typical of cutaneous leishmaniasis.

Comparison Between in Vitro Effects of Aqueous Extract of Artemisia seiberi and Artemisinin on Leishmania major.

BACKGROUND: It is necessary to develop novel, affordable, and accessible drugs with few side effects as alternatives of the currently available chemical agents for leishmaniasis. OBJECTIVES: The main purpose of this study was to evaluate the effects of these drugs on L. major under in vitro conditions. MATERIALS AND METHODS: In the current study, 5, 10, 25, 50, and 100 µg/mL concentrations of aqueous extract of Artemisia sieberi and chemical artemisinin were tested on promastigotes of Leishmania major (L. major), uninfected macrophages, and infected macrophages with intracellular amastigotes of L. major, by direct counting and 3-(4 5-dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromid methods. RESULTS: The results obtained for each drug were compared with other drugs and also with the results of the control groups. The results related to promastigote and amastigote assays showed that when the dose of both drugs increased, the parasite number is reduced in comparison with the control groups. Moreover, the parasitic burden in the test cultures decreased significantly. Macrophage assay results showed that the effects of both drugs on uninfected and healthy macrophages were very low. CONCLUSIONS: These results indicate that both drugs have anti-Leishmania effects, which was higher in Artemisia sieberi compared with artemisinin. Thus, carrying out further studies on the effects of Artemisia sieberi in infected animals with L. major is recommended.

In Vitro Antiparasitic and Apoptotic Effects of Antimony Sulfide Nanoparticles on Leishmania infantum.

Visceral leishmaniasis is one of the most important sever diseases in tropical and subtropical countries. In the present study the effects of antimony sulfide nanoparticles on Leishmania infantum in vitro were evaluated. Antimony sulfide NPs (Sb(2)S(5)) were synthesized by biological method from Serratia marcescens bacteria. Then the cytotoxicity effects of different concentrations (5, 10, 25, 50, and 100 µg/mL) of this nanoparticle were assessed on promastigote and amastigote stages of L. infantum. MTT method was used for verification results of promastigote assay. Finally, the percentages of apoptotic, necrotic, and viable cells were determined by flow cytometry. The results indicated the positive effectiveness of antimony sulfide NPs on proliferation of promastigote form. The IC(50) (50% inhibitory concentration) of antimony sulfide NPs on promastigotes was calculated 50 µg/mL. The cytotoxicity effect was dose-dependent means by increasing the concentration of antimony sulfide NPs, the cytotoxicity curve was raised and the viability curve of the parasite dropped simultaneously. Moreover, the IC(50) of antimony sulfide NPs on amastigote stage was calculated 25 µg/mL. On the other hand, however, antimony sulfide NPs have a low cytotoxicity effect on uninfected macrophages but it can induce apoptosis in promastigote stage at 3 of 4 concentrations.