Synthesis and biological evaluation of 2-arylbenzimidazoles targeting Leishmania donovani.

A set of 56 2-arylbenzimidazoles was designed, synthesized and tested against Leishmania donovani amastigotes. The left- and right-hand side rings of the molecule, as well as the amide linker were modified. Structurally different derivatives were screened on L.

Modular multiantigen T cell epitope-enriched DNA vaccine against human leishmaniasis.

The leishmaniases are protozoal diseases that severely affect large populations in tropical and subtropical regions. There are only limited treatment options and preventative measures. Vaccines will be important for prevention, control and elimination of leishmaniasis, and could reduce the transmission and burden of disease in endemic populations.

Anti-leishmanial activity of disubstituted purines and related pyrazolo[4,3-d]pyrimidines.

We report here results of screening directed to finding new anti-leishmanial drugs among 2,6-disubstituted purines and corresponding 3,7-disubstituted pyrazolo[4,3-d]pyrimidines. These compounds have previously been shown to moderately inhibit human cyclin-dependent kinases. Since some compounds reduced viability of axenic amastigotes of Leishmania donovani, we screened them for interaction with recombinant leishmanial cdc-2 related protein kinase (CRK3/CYC6), an important cell cycle regulator of the parasitic protozoan.

Anti-leishmanial activity of betulin derivatives.

Leishmanicidal activity of 24 derivatives of naturally occurring and abundant triterpenes belonging to the lupane series, betulin, betulinic acid and betulonic acid, is described in this study. The easily modified positions of the lupane skeleton, the hydroxy groups of C-3 and C-28, as well as the carbon-carbon double bond C-20-C-29 were used as a starting point to prepare a library of triterpenoid derivatives for bioactivity studies. The compounds were evaluated against Leishmania donovani axenic amastigotes on a microplate assay at 50 microM.

Synthesis and anti-leishmanial activity of heterocyclic betulin derivatives.

Betulin, a naturally occurring abundant triterpene is converted in four steps to 3,28-di-O-acetyllupa-12,18-diene. When various 4-substituted urazoles were oxidized to the corresponding urazines with iodobenzene diacetate in the presence of 3,28-di-O-acetyllupa-12,18-diene, new heterocyclic betulin derivatives were produced. These betulin derivatives were examined in a microplate assay at 50 microM for their ability to inhibit the growth of Leishmania donovani axenic amastigotes, a species that causes the fatal visceral leishmaniasis.

A new Heck reaction modification using ketone Mannich bases as enone precursors: parallel synthesis of anti-leishmanial chalcones.

A new Heck-type reaction for the synthesis of chalcones has been established using Mannich bases as enone precursors. The novel reaction proceeds rapidly in air atmosphere under ligandless conditions and can be adapted for library synthesis in a parallel reactor station. Screening of the synthesized chalcones revealed N-{4-[(1E)-3-oxo-3-(3-pyridinyl)-1-propenyl]phenyl}benzamide (3f) to be a potent anti-leishmanial agent.

2-(3-aryl-3-oxopropen-1-yl)-9-tert-butyl-paullones: a new antileishmanial chemotype.

A screening program directed to find new agents against Leishmania donovani, the parasite causing visceral leishmaniasis, revealed that paullones attenuate the proliferation of axenic amastigotes. Because these structures were not active in a test system involving infected macrophages, a structure optimization campaign was carried out. Concomitant introduction of an unsaturated side chain into the 2-position and a tert-butyl substituent into the 9-position of the parent scaffold led to compounds inhibiting also parasites dwelling in macrophages.

Effect of pH and temperature on protein kinase release by Leishmania donovani.

During their life cycle Leishmania are exposed to environments that differ markedly in pH and temperature. The effect of these factors on protein kinase release into the surrounding environment by Leishmania donovani promastigotes was examined. Promastigotes release protein kinase activity both constitutively and following induction by incubation with an exogenous substrate, phosvitin.