There are currently no ideal treatments or acceptable vaccines for cutaneous leishmaniasis, a worldwide health problem caused by infection with a number of species of the dimorphic protozoa Leishmania. Therefore, there is an urgent need to search for simple, safe, effective, and affordable treatments. Imiquimod is an immune-response modifying agent. Recently, 5% imiquimod cream (Aldara(TM)) received approval by the Food and Drug Administration in the United States and is currently available for the treatment of external genital and perianal warts caused by human papillomavirus infection. The antiviral activity of this drug is mediated through stimulation of cytokine release from many cell types including macrophages resulting in a local immune response at the site of application. Moreover, imiquimod has been shown to enhance cell-mediated immune responses (CMIR). Since imiquimod activates macrophages, the exclusive host cells of Leishmania, and stimulates CMIR which are required for host defence against Leishmania, we have investigated the potential of using imiquimod and its related compound, S-28463, as agents for treating leishmaniasis. It is demonstrated within that imiquimod and S-28463 effectively stimulated leishmanicidal activity both in vitro in macrophages and in vivo in a mouse model. These compounds also stimulated signal transduction associated with the induction of nitric oxide synthesis in macrophages. Imiquimod and S-28463 induced leishmanicidal activity in macrophages in the absence of any other cell types. We have demonstrated that S-28463 generated macrophage leishmanicidal activity by inducing genes involved in macrophage activation and inflammatory responses. Finally, we have also performed an analysis on the influence of L. donovani on macrophage gene expression using a cDNA array analysis, a similar methodology to study the effect of S-28463 on macrophage gene expression. Intramacrophage infection with L. donovani was shown to cause general

Magister Pharmaceuticae - MPharm / Plasmodium falciparum malaria continues to be a worldwide health problem, especially in developing countries in Africa and is responsible for over a million fatalities per annum. Chloroquine (CQ) is low-cost, safe and was the mainstay aminoquinoline derived chemotherapeutic agent that has been used for many years against blood-stage malaria. However, today the control of malaria has been complicated by increased resistance of the malaria parasite to existing antimalarial agents such as CQ. The primary cause of resistance is mutation in a putative ATP-powered multidrug efflux pump known as the p-glycoprotein (pGP) pump, and point mutation in P. falciparum CQ resistance transporter (PfCRT) protein. These mutations are responsible for the reduced accumulation of CQ at its primary site of action, the acidic digestive food vacuole of the parasite.To overcome the challenges of CQ resistance in P. falciparum, chemosensitiser offer an attractive approach. Chemosensitisers or reversal agents are structurally diverse molecules that are known to reverse CQ resistance by inhibiting the pGP efflux pump and/or the PfCRT protein associated with CQ export from the digestive vacuole in CQ resistant parasites. Chemosensitisers include the well-studied calcium channel blocker verapamil and antihistaminic agent chlorpheniramine. These drugs have little or no inherent antimalarial activity but have shown to reverse CQ resistance in P. falciparum when co-administered with CQ. Because of the channel blocking abilities of pentacycloundecylamines (PCUs) such as NGP1-01, it is postulated that these agents may act as chemosensitisers and circumvent the resistance of the Plasmodium parasite against CQ. Therefore as a proof of concept we conducted an experiment using CQ co- administered with different concentrations of NGP1-01 to evaluate the ability of NGP1-01 to act as a chemosensitiser.Herein, we report the ability of NGP1-01, the prototype pentacycloundecylamine (PCU), to reverse CQ resistance (> 50 %) and act as a chemosensitiser. NGP1-01 alone exhibited very low intrinsic antimalarial activity against both the resistant and sensitive strain (> 2000 nM), with no toxicity to the parasite detected at 10 µM. A statistically significant (p < 0.05) dose dependent shift was seen in the CQ IC50 values at both 1 µM and 10 µM concentration of co-administeredNGP1-01 against the resistant strain. Based on this finding we set out to synthesise a series of novel agents comprising of a PCU moiety as the reversal agent (RA) conjugated to a CQ-like aminoquinoline (AM) molecule and evaluate the potential of these PCU-AM derivatives as antimalarial- and/or reversed CQ agents. As recently shown by Peyton et al., (2012), the conjugation of a CQ-like molecule with a RA such as the chemosensitiser imipramine and derivatives thereof is a viable strategy to reverse CQ resistance in multidrug-resistant P. falciparum. The novel compounds were obtained by amination and reductive amination reactions. The synthetic procedures involved the conjugation of the Cookson’s diketone with different tethered 4-aminoquinoline moieties to yield the respective carbinolamines and the subsequent imines. This was followed by a transannular cyclisation using sodium cyanoborohydride as reducing agent to yield the desired PCU-AM derivatives. The CQ-like AMderivatives were obtained using a novel microwave (MW) irradiation method. Structure elucidation was done by utilising 1H- and 13C NMR spectroscopy as well as IR absorption spectrophotometry and mass spectrometry. Five PCU-AM reversed CQ derivatives were successfully synthesised and showed significant in vitro antimalarial activity against the CQ sensitive strain (NF54). PCU-AM derivatives 1.1 – 1.4 showed antimalarial IC50 values in the ranges of 3.74 – 17.6 ng/mL and 27.6 – 253.5 ng/mL against the CQ-sensitive (NF54) and CQ-resistant strains (Dd2) of Plasmodium falciparum, respectively. Compound 1.1 presented with the highest antimalarial activity against both strains and was found to be 5 fold more active against the resistant strain than CQ. The reversed CQ approach resulted in improved resistance reversal and a significantly lower concentration PCU was required compared to NGP1-01 and CQ in combination. This may be attributed to the improved ability of compound 1.1 to actively block the pGP pump and/or the increased permeability thereof because of the lipophilic aza-PCU moiety. Compound 1.1 also showed the lowest RMI value confirming that this compound has the best potential to act as a reversed CQ agent in the series. Cytotoxicity IC50 values observed for compounds 1.1 – 1.4 were in the low micromolar concentrations (2.39 – 9.54 µM) indicating selectivity towards P. falciparum (SI = 149 – 2549) and low toxicity compared to the cytotoxic agent emetine (IC50 = 0.061 µM).These results indicate that PCU channel blockers and PCU-AM derived conjugates can be utilised as lead molecules for further optimisation and development to enhance their therapeuticpotential as reversal agents and reversed CQ compounds.

No description available.

No / A series of 19 huprines has been evaluated for their activity against cultured bloodstream forms of Trypanosoma brucei and Plasmodium falciparum. Moreover, cytotoxicity against rat myoblast L6 cells was assessed for selected huprines. All the tested huprines are moderately potent and selective trypanocidal agents, exhibiting IC50 values against T. brucei in the submicromolar to low micromolar range and selectivity indices for T. brucei over L6 cells of approximately 15, thus constituting interesting trypanocidal lead compounds. Two of these huprines were also found to be active against a chloroquine-resistant strain of P. falciparum, thus emerging as interesting trypanocidal–antiplasmodial dual acting compounds, but they exhibited little selectivity for P. falciparum over L6 cells.

Yes / Current drugs against human African trypanosomiasis (HAT) suffer from several serious drawbacks. The search for novel, effective, brain permeable, safe, and inexpensive antitrypanosomal compounds is therefore an urgent need. We have recently reported that the 4-aminoquinoline derivative huprine Y, developed in our group as an anticholinesterasic agent, exhibits a submicromolar potency against Trypanosoma brucei and that its homo- and hetero-dimerization can result in to up to three-fold increased potency and selectivity. As an alternative strategy towards more potent smaller molecule anti-HAT agents, we have explored the introduction of ω-cyanoalkyl, ω-aminoalkyl, or ω-guanidinoalkyl chains at the primary amino group of huprine or the simplified 4-aminoquinoline analogue tacrine. Here, we describe the evaluation of a small in-house library and a second generation of newly synthesized derivatives, which has led to the identification of 13 side chain modified 4-aminoquinoline derivatives with submicromolar potencies against T. brucei. Among these compounds, the guanidinononyltacrine analogue 15e exhibits a 5-fold increased antitrypanosomal potency, 10-fold increased selectivity, and 100-fold decreased anticholinesterasic activity relative to the parent huprine Y. Its biological profile, lower molecular weight relative to dimeric compounds, reduced lipophilicity, and ease of synthesis, make it an interesting anti-HAT lead, amenable to further optimization to eliminate its remaining anticholinesterasic activity. / Wellcome Trust

Nitric oxide (NO) has been shown to be lethal for a variety of intracellular pathogens including Leishmania. In murine models, the inducible nitric oxide synthase gene (iNOS) is expressed in activated macrophages and is involved in the synthesis of NO. Because the role of NO and iNOS in human leishmaniasis was less clear, we examined the expression of the iNOS gene in human macrophages infected with Leishmania in vitro and in biopsy tissue from subjects with cutaneous leishmaniasis. / Pentavalent antimony (Sb5+) in the form of Pentostam(TM) or Glucantime(TM) is still the treatment of choice despite its toxicity. Aldara(TM) (5% imiquimod) is an immune-response modifying agent that has been approved by the Food and Drug Administration in the USA for treating genital warts caused by papillomaviruses. We conducted an open-label, prospective study of combined Glucantime(TM) + Aldara(TM) therapy in subjects with CL who had previously failed a complete course of Glucantime(TM) treatment at regular doses. (Abstract shortened by UMI.)

Diferent classes of antimalarial drugs have been used to treat malaria, but the emergence of resistant strains of Plasmodium these drugs have decreased their efficiency, causing serious public health problem in tropical areas of the world. In this context, we carried out the preparation and antimalarial evaluation of eleven organic compounds: 7-Cl-MAQ, MAQPZ, 7-Cl-MAQPZ, 2-CF3-MAQ, 7-CF3-MAQ, 7-CF3-MAQPZ, 2-CF3-MAQPZ, 8-Cl-MAQ, 7-Cl-BAQ, 7-CF3-BAQ, 8-Cl-BAQ. These were obtained from the same synthetic strategy, via nucleophilic aromatic substitution reaction between 4-chloroquinoline derivatives and diethylenetriamine or 1,2-(aminoethyl) piperazine, reaching moderated to high yields. These compounds were designed based on the molecular structure of chloroquine, a classic antimalarial drug. As for antimalarial activity, only four substances (7-Cl-MAQ, BAQ, 2-CF3-MAQ and 7-CF3-MAQ) were evaluated. Note that the 7-Cl-MAQ was more active in in vitro and in vivo that the BAQ. The same behavior occurred in cytotoxicity assays, with higher values than the BAQ. In in vivo tests, the monoquinolínico derivative (7-Cl-MAQ) significantly reduced parasitemia. Have the 2-CF3-MAQ compounds and 7-CF3-MAQ, were active in vitro, but were inactive in vivo. Keywords: 4-aminoquinolinic derivatives, antimalarials, chloroquine. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Várias classes de antimaláricos têm sido utilizadas para o tratamento da malária, porém o surgimento de cepas de Plasmodium resistentes a esses fármacos têm diminuído suas eficácias, provocando graves problemas de saúde pública em áreas tropicais do mundo. Nesse contexto, realizou-se a preparação, caracterização e avaliação antimalárica de onze derivados aminoquinolínicos: 7-Cl-MAQ, MAQ, MAQPZ, 7-Cl-MAQPZ, 2-CF3-MAQ, 7-CF3-MAQ, 7-CF3-MAQPZ, 2-CF3-MAQPZ, 8-Cl-MAQ, 7-Cl-BAQ, 7-CF3-BAQ, 8-Cl-BAQ. Estes foram obtidos através da mesma estratégia sintética, via reação de substituição nucleofílica aromática, a partir da reação entre derivados de 4-cloroquinolinas com dietilenotriamina ou 1,2-(aminoetil)piperazina, chegando a rendimentos moderados altos a. Estes compostos foram elaborados baseados na estrutura molecular da cloroquina, um clássico fármaco antimalárico. Quanto à atividade antimalárica, apenas quatro substâncias (7-Cl-MAQ, BAQ, 2-CF3-MAQ e 7-CF3-MAQ) foram avaliadas. Vale destacar que a 7-Cl-MAQ foi mais ativa nos testes in vitro e in vivo que a BAQ. O mesmo comportamento ocorreu nos ensaios de citotoxicidade, apresentando valores maiores que a BAQ. Nos testes in vivo, o derivado monoquinolínico (7-Cl-MAQ) reduziu significativamente a parasitemia. Já os compostos 2-CF3-MAQ e 7-CF3-MAQ, mostraram-se ativos in vitro, porém foram inativos in vivo.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-21T15:25:14Z No. of bitstreams: 1 lucianamariaribeiroantinarelli.pdf: 3736513 bytes, checksum: 7a35a693236ba9e982e630b172b6f3cf (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:10:52Z (GMT) No. of bitstreams: 1 lucianamariaribeiroantinarelli.pdf: 3736513 bytes, checksum: 7a35a693236ba9e982e630b172b6f3cf (MD5) / Made available in DSpace on 2017-08-07T19:10:52Z (GMT). No. of bitstreams: 1 lucianamariaribeiroantinarelli.pdf: 3736513 bytes, checksum: 7a35a693236ba9e982e630b172b6f3cf (MD5) Previous issue date: 2013-02-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A quimioterapia atual para as leishmanioses está longe do ideal devido a uma série de problemas como alto custo e elevada toxicidade. Assim, existe uma necessidade imediata de obtenção de novos fármacos para o tratamento da doença. Neste contexto, derivados de quinolina têm demonstrado atividade leishmanicida promissora. Neste trabalho, foi avaliada a atividade leishmanicida de duas séries distintas de quinolinas: seis compostos derivados de 4-aminoquinolinas (4-AMQ) e seus híbridos com esteroide e nove derivados da amodiaquina (AQ). O efeito dos compostos foi testado em promastigotas e amastigotas de Leishmania sp e em macrófagos peritoneais de camundongos. Os resultados mostraram que a conjugação de 4-AMQ ao esteroide resultou em aumento significativo da atividade principalmente para formas promastigotas e amastigotas de L. major. O composto 6 foi o mais ativo em amastigota de L. major (CI50 de 1,9 µM), sendo três vezes mais efetivo do que a miltefosina. Demonstrou-se neste trabalho que a conjugação de dois grupos de grande aplicação biológica, quinolina e esteroide, pode ser uma estratégia interessante para o desenvolvimento racional de novos fármacos. Em relação aos derivados da AQ, observou-se que a grande maioria dos compostos foram ativos em promastigotas e amastigotas de Leishmania sp. Dentre os nove compostos avaliados, seis foram mais ativos em amastigotas de L. braziliensis do que o protótipo AQ e miltefosina. O composto 8 (CI50 de 0,4 µM) foi cerca de quatorze vezes mais ativo em amastigota do que a miltefosina. A maioria dos derivados de 4-AMQ e AQ foram mais seletivos e específicos para amastigotas. A atividade em potencial dos compostos avaliados pode ser considerada um importante avanço no estudo desta classe de derivados, visando-se o desenvolvimento de novos fármacos leishmanicidas mais eficazes, seletivos e não tóxicos para o hospedeiro humano. / Current chemotherapy for leishmaniasis is far from ideal due to a number of problems such as high cost and high toxicity. Thus, there is an immediate need to obtain new drugs for the treatment the disease. In this context, quinoline derivatives have shown promising antileishmanial activity. In this study, we evaluated the activity of two distinct series of quinolines, six 4-aminoquinolines (4-AMQ) derivatives and their hybrids with steroid and nine amodiaquine (AQ) derivatives in different Leishmania species. Effect of the compounds was assayed against Leishmania promastigotes and amastigotes and mouse peritoneal macrophages. Results showed that the combination of 4-AMQ to the steroid resulted in a significant increase in activity mainly for L. major promastigotes and amastigotes forms. Compound 6 was the most active against L. major amastigotes with IC50 of 1.9 µM, being three times more effective than miltefosine. It was demonstrated in this work that the combination of two groups with large biological application as quinoline derivatives and steroids may be an interesting strategy for the rational development of new drugs. Regarding to the AQ derivatives, it was observed that all compounds were most active against Leishmania promastigote and amastigote forms. Among the nine compounds evaluated, six were more active against L. braziliensis amastigotes than the prototype AQ and miltefosine. Compound 8 with IC50 of 0.4 µM was about fourteen times more active than miltefosine. In general, the majority of 4-AMQ and AQ derivatives are more selective and specific for amastigotes of Leishmania sp, forms clinically relevant. Potential activity of the compounds evaluated can be considered an important advance in the study of this class of derivatives in order to develop new leishmanicidal drugs more effective, selective and nontoxic to the human host.

No description available.

We have synthesized a series of dimers of (+)-(7R,11R)-huprine Y and evaluated their activity against Trypanosoma brucei, Plasmodium falciparum, rat myoblast L6 cells and human acetylcholinesterase (hAChE), and their brain permeability. Most dimers have more potent and selective trypanocidal activity than huprine Y and are brain permeable, but they are devoid of antimalarial activity and remain active against hAChE. Lead optimization will focus on identifying compounds with a more favourable trypanocidal/anticholinesterase activity ratio.