RESUMO
The present study determined the anti-Mycobacterium tuberculosis activities of supercritical CO2 extracts, neolignans eupomatenoid-5 (1), conocarpan (4) and eupomatenoid-3 (7) and their derivatives (2, 3, 5, 6, and 8) from Piper regnellii, as well as their cytotoxicities. The supercritical CO2 extract from leaves was purified by chromatographic methods, yielding compounds (1), (4) and (7), which were identified by (1)H NMR and comparison with literature data. Anti-M. tuberculosis activity (H37Rv and clinical isolates) was evaluated using a resazurin microtiter assay plate (REMA) to determine the MIC. The cytotoxicity assay was carried out in macrophages J774G.8 by sulforhodamine B colorimetric assay. The supercritical CO2 extracts from leaves and stems, and compound (4) showed activity against M. tuberculosis (MIC 15.6 µg/ml). Compound (1) showed the best activity (MIC 1.9 µg/ml), with good SI. Compounds (7) and (8) showed low activity against M. tuberculosis H37Rv. The derivative compounds did not show increased anti-M. tuberculosis activity. This is the first report, to our knowledge, to describe neolignans from P. regnellii with activity against M. tuberculosis, and compound (1) is a potential candidate for future antituberculosis drugs.
Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Piper/química , Extratos Vegetais/química , Animais , Antituberculosos/química , Benzofuranos/química , Benzofuranos/farmacologia , Linhagem Celular/efeitos dos fármacos , Lignanas/química , Lignanas/farmacologia , Macrófagos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/análise , Testes de Toxicidade/métodosRESUMO
We have previously demonstrated antileishmanial activity on Leishmania amazonensis of the natural (1-2), synthetic (7) and derivatives of coumarin (-) mammea A/BB (3-6) isolated from the dichloromethane extract of Calophyllum brasiliense leaves. The aim of the present study was to evaluate morphological and ultrastructural alterations in Leishmania amazonensis induced by these compounds. In promastigote forms, all seven compounds produced significant morphological and ultrastructural alterations, as revealed by scanning and transmission electron microscopy. The compound 5,7-dihydroxy-8-(2-methylbutanoyl)-6-(3-methylbutyl)-4-phenyl-chroman-2-one (3), the most active antileishmanial with LD50 of 0.9 µM), induced cell shrinkage and a rounded appearance of the cells. Parasites incubated in the presence of compound (3) showed ultrastructural changes, such as the appearance of mitochondrial swelling with a reduction in the density of the mitochondrial matrix and the presence of vesicles inside the mitochondrion, indicating damage and significant change in this organelle; abnormal chromatin condensation, alterations in the nuclear envelope, intense atypical cytoplasmic vacuolization, and the appearance of autophagic vacuoles were also observed. In addition, the compound (3) may be acting to depolarize the mitochondrial membrane potential of the cells, leading to death of the parasite.
Assuntos
Antiprotozoários/farmacologia , Calophyllum/química , Cumarínicos/química , Leishmania mexicana/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Folhas de Planta/química , Antiprotozoários/química , Antiprotozoários/isolamento & purificação , Cromanos/isolamento & purificação , Cromanos/farmacologia , Cromatina/efeitos dos fármacos , Citometria de Fluxo , Concentração Inibidora 50 , Leishmania mexicana/ultraestrutura , Potencial da Membrana Mitocondrial , Microscopia Eletrônica , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/ultraestrutura , Membrana Nuclear/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Extratos Vegetais/química , Extratos Vegetais/farmacologiaRESUMO
We show that ethyl 2-oxo-2H-chromene-3-carboxylate (EOCC), a synthetic coumarin, irreversibly inhibits phospholipase A(2) (sPLA2) from Crotalus durissus ruruima venom (sPLA2r) with an IC(50) of 3.1 +/- 0.06 nmol. EOCC strongly decreased the V(max) and K(m), and it virtually abolished the enzyme activity of sPLA2r as well as sPLA2s from other sources. The edema induced by sPLA2r + EOCC was less than that induced by sPLA2r treated with p-bromophenacyl bromide, which was more efficient at neutralizing the platelet aggregation activity of native sPLA2r. Native sPLA2r induced platelet aggregation of 91.54 +/- 9.3%, and sPLA2r + EOCC induced a platelet aggregation of 18.56 +/- 6.5%. EOCC treatment also decreased the myotoxic effect of sPLA2r. Mass spectrometry showed that EOCC formed a stable complex with sPLA2r, which increased the mass of native sPLA2r from 14,299.34 Da to 14,736.22 Da. Moreover, the formation of this complex appeared to be involved in the loss of sPLA2r activity. Our results strongly suggest that EOCC can be used as a pharmacological agent against the sPLA2 in Crotalus durissus sp. venom as well as other sPLA2s.
Assuntos
Antivenenos/farmacologia , Cumarínicos/farmacologia , Venenos de Crotalídeos/enzimologia , Crotalus/fisiologia , Edema/prevenção & controle , Inibidores de Fosfolipase A2 , Agregação Plaquetária/efeitos dos fármacos , Animais , Edema/induzido quimicamente , Inibidores Enzimáticos/farmacologia , Masculino , Fosfolipases A2/farmacologia , Ratos , Ratos WistarRESUMO
The structure of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi complexed with chalepin, a natural product from Pilocarpus spicatus, has been determined by X-ray crystallography to 1.95 A resolution. The structure is in the apo form without cofactors in the subunits of the tetrameric gGAPDH in the asymmetric unit. Unequivocal density corresponding to the inhibitor was clearly identified in one monomer. The final refined model of the complex shows extensive conformational changes when compared with the native structure. The mode of binding of chalepin to gGAPDH and its implications for inhibitor design are discussed.
Assuntos
Furocumarinas/química , Gliceraldeído-3-Fosfato Desidrogenases/química , Microcorpos/enzimologia , Trypanosoma cruzi/enzimologia , Animais , Cristalização , Cristalografia por Raios X , Furocumarinas/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/genética , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Substâncias Macromoleculares , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade , Trypanosoma cruzi/genéticaRESUMO
The development of Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens was inhibited in vitro by synthetic compounds containing the piperonyl group. In addition, worker ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls. The inhibition of the fungal growth increased with the size of the carbon side chain ranging from C1 through C8 and decreasing thereafter. 1-(3,4-Methylenedioxybenzyloxy)octane (compound 5) was the most active compound and inhibited the fungal development by 80% at a concentration of 15 micrograms ml-1. With worker ants the toxic effects started with compound 5 and increased with the number of carbons in the side chain. Thus, for the same concentration (100 micrograms ml-1) the mortality rates observed after 8 days of diet ingestion were 82%, 66% and 42%, for 1-(3,4-methylenedioxybenzyloxy)decane, 1-(3,4-methylenedioxybenzyloxy)dodecane and compound 5, respectively, whereas with commercial piperonyl butoxide the mortality was 68%. The latter compound, which is known as a synergist insecticide, was as inhibitory to the symbiotic fungus as the synthetic compound 5. The possibility of controlling these insects in the future using compounds that can target simultaneously both organisms is discussed.