RESUMO
New oral treatments are needed for all forms of leishmaniasis. Here, the improved oral efficacy of quercetin (Qc) and its penta-acetylated derivative (PQc) was evaluated in cutaneous leishmaniasis after encapsulation in lipid-core nanocapsules (LNCs) of poly(ε-caprolactone). Leishmania amazonensis-infected BALB/c mice were given 51 daily oral doses of free drugs (16 mg kg-1) or LNC-loaded drugs (0·4 mg kg-1). While treatment with free Qc reduced the lesion sizes and parasite loads by 38 and 71%, respectively, LNC-Qc produced 64 and 91% reduction, respectively. The antileishmanial efficacy of PQc was similar but not as potently improved by encapsulation as Qc. None of the treatments increased aspartate aminotransferase, alanine aminotransferase or creatinine serum levels. These findings indicate that when encapsulated in LNC, Qc and, to a lesser extent, PQc can safely produce an enhanced antileishmanial effect even at a 40-fold lower dose, with implications for the development of a new oral drug for cutaneous leishmaniasis.
Assuntos
Leishmania mexicana/efeitos dos fármacos , Nanocápsulas , Poliésteres/análise , Quercetina/farmacologia , Tripanossomicidas/farmacologia , Animais , Feminino , Leishmaniose Cutânea/tratamento farmacológico , Lipídeos/análise , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Leishmania amazonensis promastigotes are known to express furosemide (Lasix®)-sensitive P-type membrane Na+-ATPase. In the present study, furosemide activity was studied in intracellular amastigotes and infected BALB/c mice to investigate its efficacy in cutaneous leishmaniasis (CL). Intracellular parasites, but not macrophages, were found to be sensitive to killing by furosemide (IC50 = 87 µ m vs CC50 â« 1000 µ m, respectively). Although furosemide did not induce nitric oxide production or intracellular pH changes in infected macrophages, it led to a significant reactive oxygen species (ROS) burst. Freshly isolated tissue parasites expressed a high degree of Na+-ATPase activity that decreased with culture, indicative of a higher enzyme expression in amastigotes than in promastigotes. Both intraperitoneal and oral treatment of L. amazonensis-infected mice with furosemide dosages equivalent to that prescribed as a diuretic significantly reduced the parasite's growth compared with the situation in untreated mice. Combination with oral furosemide increased the efficacy and safety of intraperitoneal treatment with sodium stibogluconate (SSG). To summarize, furosemide control of intracellular leishmanial growth by means of parasite Na+-ATPase inhibition, and macrophage ROS activation may help explain its sole and SSG-combined therapeutic effect against murine CL.
Assuntos
Furosemida/farmacologia , Leishmania/efeitos dos fármacos , Tripanossomicidas/farmacologia , Adenosina Trifosfatases/antagonistas & inibidores , Animais , Proteínas de Transporte de Cátions/antagonistas & inibidores , Diuréticos/farmacologia , Feminino , Leishmaniose Cutânea , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Previously, we showed that treating macrophages with ATP impairs the intracellular growth of Leishmania amazonensis, and that the P2X7 purinergic receptor is overexpressed during leishmaniasis. In the present study, we directly evaluated the effect of periodate-oxidized ATP (oATP) on parasite control in Leishmania-infected macrophages. We found that oATP impaired the attachment/entrance of L. amazonensis promastigotes to C57BL/6 mouse macrophages in a P2X7 receptor-independent manner, as macrophages from P2X7(-/-) mice were similarly affected. Although oATP directly inhibited the growth of axenic promastigotes in culture, promoted rapid ultrastructural alterations, and impaired Leishmania internalization by macrophages, it did not affect intracellular parasite multiplication. Upon infection, phagosomal acidification was diminished in oATP-treated macrophages, accompanied by reduced endosomal proteolysis. Likewise, MHC class II molecules expression and ectoATPase activity was decreased by oATP added to macrophages at the time of parasite infection. These inhibitory effects were not due to a cytotoxic effect, as no additional release of lactate dehydrogenase was detected in culture supernatants. Moreover, the capacity of macrophages to produce nitric oxide and reactive oxygen species was not affected by the presence of oATP during infection. We conclude that oATP directly affects extracellular parasite integrity and macrophage functioning.
Assuntos
Trifosfato de Adenosina/análogos & derivados , Leishmaniose/tratamento farmacológico , Leishmaniose/imunologia , Macrófagos/imunologia , Receptores Purinérgicos P2X7/genética , Trifosfato de Adenosina/farmacologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Células da Medula Óssea/parasitologia , Antígenos de Histocompatibilidade Classe II/biossíntese , L-Lactato Desidrogenase/metabolismo , Leishmania/imunologia , Leishmaniose/parasitologia , Macrófagos/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/biossíntese , Espécies Reativas de Oxigênio/metabolismoRESUMO
The interest in developing new sunscreens is increasing due to the harmful effects of UV radiation on the skin, such as erythema, accelerated skin ageing (photoageing) and the induction of skin cancer. However, many molecular sunscreens penetrate into the skin causing photoallergies, phototoxic reactions and skin irritation. Thus, the aim of this work was the preparation and characterization of polymeric and solid lipid nanoparticles to act carriers of benzophenone-3 (BZ3), aiming to improve the safety of sunscreen products by increasing the sun protection factor (SPF), decreasing BZ3 skin penetration and decreasing BZ3 concentration in sunscreen formulation. BZ3 was encapsulated in poly(epsilon-caprolactone) (PCL) nanoparticles by the nanoprecipitation method and in solid lipid nanoparticles (SLN) by the hot high pressure homogenization method. The particles were stable for 40 days. The BZ3 encapsulated in PCL nanoparticles was released faster than BZ3 encapsulated in SLN. The sun protection factor increased when BZ3 was encapsulated in both nanostructures. However, BZ3 encapsulated in PCL nanoparticles decreased its skin permeation more than SLN-BZ3. Furthermore, BZ3 encapsulated in SLN did not exhibit cytotoxic or phototoxic effects in human keratinocytes (HaCaT cells) and BABL/c 3T3 fibroblasts, whereas PCL nanoparticles with BZ3 showed phototoxic potential in HaCaT cells. Nevertheless, BZ3 free and encapsulated in PCL nanoparticles or in SLN did not show allergic reactions in mice. Our results suggest that these nanostructures are interesting carriers for sunscreen.
Assuntos
Lipídeos/química , Nanocápsulas/química , Polímeros/química , Absorção Cutânea/fisiologia , Pele/efeitos dos fármacos , Protetores Solares/química , Protetores Solares/farmacocinética , Administração Tópica , Animais , Humanos , Camundongos , Nanocápsulas/administração & dosagem , Protetores Solares/administração & dosagemRESUMO
Previously, we described the protective action of the immunomodulatory extract of Kalanchoe pinnata (Kp) in murine and human cutaneous leishmaniasis. In the present study, we investigated the effectiveness of Kp against visceral leishmaniasis, using the BALB/c mouse model of infection with Leishmania chagasi. Mice receiving oral daily doses of Kp (400 mg/kg) for 30 days displayed significantly reduced hepatic and splenic parasite burden, when compared with untreated animals. Protectiveness was accompanied by a reduction in parasite-specific IgG serum levels, and impaired capacity of spleen cells to produce IL-4, but not IFN-gamma and nitric oxide upon antigen recall in vitro. The reference drug Pentostam (72 mg/kg) given by the intra-peritoneal route on alternate days produced an anti-leishmanial effect similar to oral Kp. Our findings show that the oral efficacy of Kp, seen previously in murine cutaneous leishmaniasis, extends also to visceral leishmaniasis caused by L. chagasi, a difficult to treat and lethal disease of man.
Assuntos
Kalanchoe/imunologia , Leishmania , Leishmaniose Visceral/tratamento farmacológico , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Anticorpos Antiprotozoários/sangue , Células Cultivadas , Feminino , Interleucina-4/biossíntese , Leishmaniose Visceral/sangue , Fígado/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Folhas de Planta/imunologia , Baço/imunologia , Baço/parasitologiaRESUMO
Previously, we reported the immunosuppressive action of the aqueous extract of Kalanchoe pinnata (Kp) in mice. In the present study, we report on the protective effect of Kp in fatal anaphylactic shock, likewise a Th2-driven immunopathology, and the identification of its active component. Mice daily treated with oral Kp during hypersensitization with ovalbumin were all protected against death when challenged with the allergen, as compared with the 100% mortality in the untreated group. A single intraperitoneal dose 3 h prior to challenge was partially effective. Oral protection was accompanied by a reduced production of OVA-specific IgE antibodies, reduced eosinophilia, and impaired production of the IL-5, IL-10 and TNF-alpha cytokines. In vitro, Kp prevented antigen-induced mast cell degranulation and histamine release. Oral treatment with the quercitrin flavonoid isolated from Kp prevented fatal anaphylaxis in 75% of the animals. These findings indicate that oral treatment with Kp effectively downmodulates pro-anaphylactic inducing immune responses. Protection achieved with quercitrin, although not maximal, suggests that this flavonoid is a critical component of Kp extract against this extreme allergic reaction.
Assuntos
Anafilaxia/tratamento farmacológico , Imunossupressores/uso terapêutico , Kalanchoe , Fitoterapia , Extratos Vegetais/uso terapêutico , Quercetina/análogos & derivados , Animais , Citocinas/biossíntese , Eosinofilia/prevenção & controle , Imunoglobulina E/biossíntese , Ativação Linfocitária , Masculino , Mastócitos/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Quercetina/uso terapêutico , Ratos , Células Th2/imunologiaRESUMO
Sixteen not new aromatic compounds were prepared by one-pot reaction i.e. through Baylis-Hillman reaction and were the first time evaluated against promastigote Leishmania amazonensis and infected mammalian cells. Most of the compounds were selectively more active against amastigotes than the reference drug sodium stibogluconate (Pentostam, IC(50)=44.7 microM). We found that 3-hydroxy-2-methylene-3-(4-bromophenyl) propanenitrile (13) was the most active (IC(50)=12.5 microM) and safer compound (0.0 (0.9); % macrophage LDH release), being the lead compound.
Assuntos
Leishmania/efeitos dos fármacos , Nitrilas/síntese química , Tripanossomicidas/síntese química , Animais , Técnicas In Vitro , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Camundongos , Nitrilas/química , Nitrilas/farmacologia , Relação Estrutura-Atividade , Tripanossomicidas/química , Tripanossomicidas/farmacologiaRESUMO
The murine model of ovalbumin (OVA)-induced allergy was used to evaluate the effectiveness of oral treatment with the leaf extract of Cissampelos sympodialis Eichl. (Menispermaceae) (CS) in the modulation of immunoglobulin E (IgE) production and T cell activation. CS treatment with doses ranging from 200 to 600 mg/Kg/day for 15 days before and during OVA-sensitization promoted reduction in total and OVA-specific serum IgE. CS at 400 or 600 mg/Kg/day also reduced paw edema induced by local OVA challenge. Daily intake of up to 600 mg/Kg of oral CS by BALB/c mice did not reduce weight gain, which is indicative of a lack of systemic toxicity. To assess the effect of CS treatment on T cell proliferative response to stimuli in vitro, the mitogenic response of spleen cells of treated and control animals were evaluated. Cells from CS-treated animals showed an elevated background proliferative response to concanavalin-A (Con-A) when compared to those from control animals. Oral intake of CS increased the in vitro production of IFN-gamma and IL-10 by Con-A stimulated cells. Mice treated with 200 mg/Kg/day CS showed increasing levels of IFN-gamma. These results show that oral treatment with Cissampelos sympodialis extract has an immunomodulatory effect, reducing allergy-associated responses possibly by a preferential activation of Th1-type cytokines.
Assuntos
Cissampelos , Citocinas/biossíntese , Imunoglobulina E/sangue , Ovalbumina/toxicidade , Células Th1/efeitos dos fármacos , Administração Oral , Animais , Edema/sangue , Edema/induzido quimicamente , Edema/tratamento farmacológico , Feminino , Imunoglobulina E/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/isolamento & purificação , Folhas de Planta , Ratos , Ratos Wistar , Células Th1/metabolismoRESUMO
The inhibiting activity of triterpenoids isolated from the methanolic extract of Pourouma guianensis (Moraceae) leaves is described for promastigotes and intracellular amastigotes of Leishmania amazonensis. Whereas the fractions containing apigenin, friedelin, epi-friedelinol, arjunolic acid, hyptatic acid B, stigmasterol and sitosterol were of no or relatively low inhibitory activity, fractions containing tormentic acid, 2alpha,3beta-dihydroxyursan-12-en-28-oic acid, 2alpha,3beta-dihydroxyolean-12-en-28-oic acid, oleanolic acid and ursolic acid were very potent in inhibiting promastigote growth at 100 microg/ml. Of the eleven isolated compounds, however, only ursolic acid and oleanolic acid showed high activity against intracellular amastigotes (IC50 value = 27 microg/ml and 11 microg/ml, respectively), which was superior to the control drug Glucantime (IC50 value = 83 microg/ml). The antileishmanial activity of oleanolic acid was directed against the parasite and not due to activation of nitric oxide intermediates by macrophages, but this triterpenoid also significantly inhibited the phagocytic capacity of those cells at concentrations above 40 microg/ml, indicating a cytotoxic effect. These results indicate that Pourouma guianensis contains many triterpenoids and some, such as ursolic and oleanolic acids, may serve as lead compounds for new antileishmanial drugs, but chemical modifications may be necessary to avoid unselective cytotoxicity.
Assuntos
Antiprotozoários/farmacologia , Leishmania/efeitos dos fármacos , Moraceae , Fitoterapia , Extratos Vegetais/farmacologia , Animais , Antiprotozoários/administração & dosagem , Antiprotozoários/uso terapêutico , Humanos , Concentração Inibidora 50 , Leishmaniose/tratamento farmacológico , Camundongos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Folhas de Planta , Triterpenos/administração & dosagem , Triterpenos/farmacologia , Triterpenos/uso terapêuticoRESUMO
Previously we demonstrated that Kalanchoe pinnata (KP) leaf extracts inhibited in vitro lymphocyte proliferation and showed in vivo immunosuppressive activity. Here we attempt to identify the immunosuppressive substances present in KP guided by the lymphoproliferative assays. From the ethanolic extract was purified a fraction (KP12SA) twenty-fold more potent to block murine lymphocyte proliferation than the crude extract. Chemical analysis by 1H- and 13C-NMR, IR and GC-MS of KP12SA (methylated sample) showed 89.3% of palmitic acid (C16), 10.7% of stearic acid (C18) and traces of arachidic (C20) and behenic acids (C22). This study provides evidence that fatty acids present in Kalanchoe pinnata may be responsible, at least in part, for its immunosuppressive effect in vivo.