Effects of cytochalasin E on Paracoccidioides brasiliensis.

AIMS: To determine the effects of cytochalasin E, isolated from the extremophile fungus Aspergillus felis, on the cells of Paracoccidioides brasiliensis Pb18. METHODS AND RESULTS: Cytochalasin E showed a minimal inhibitory concentration of 3·6 µmol l-1 and minimum fungicidal concentration of 7·2 µmol l-1 on P. brasiliensis by in vitro microdilution and IC50 >964·0 µmol l-1 on murine macrophages. Its selectivity index (>263) indicated that this compound has selectivity for fungal cells. Morphological alterations were determined by optical and fluorescence microscopy, as well as scanning and transmission electron microscopy. Cytochalasin E affected P. brasiliensis bud-forming pseudohyphae, cell morphology, cell walls and cell membranes; caused the release of cellular material; and resulted in the production of reactive oxygen species. In murine macrophages, it affected cytoskeletal actin and inhibited phagocytosis. CONCLUSION: Cytochalasin E may be useful as an antifungal prototype against P. brasiliensis and in studies on phagocytosis. SIGNIFICANCE AND IMPACT OF THE STUDY: Paracoccidioides spp. are the etiological agents of paracoccidioidomycosis (PCM). Treatment is prolonged to control the clinical manifestations and prevent relapse. The study on the effects of cytochalasin E in P. brasiliensis is important because it can be used as a prototype for new antifungal drugs and consequently, broadens the treatment options for PCM.

Constituents from stem barks of Luehea ochrophylla Mart and evaluation of their antiparasitic, antimicrobial, and antioxidant activities.

Luehea species are found in almost all Central and South American countries. The present work describes the phytochemical study, isolation, and structural characterisation of friedelin, ß-friedelinol, lupeol, pseudotaraxasterol, ß-sitosterol, betulinic acid, taraxasterol, (-)-epicatechin, ß-sitosterol-3-O-ß-d-glucopyranoside, and (+)-epicatechin-(4ß→8)-epicatechin from stem barks of Luehea ochrophylla Mart. The structural identification of the isolated compounds was mainly performed by NMR analyses and comparison with the data from literature. These compounds were isolated for the first time in the genus Luehea, except ß-sitosterol glucopyranoside, (-)-epicatechin, and lupeol. Hexane extract (HE) and dichloromethane (DF) and ethyl acetate (AF) fractions exhibited antiparasitic activity against amastigote (intracellular) and trypomastigote culture forms of Trypanosoma cruzi. The ethanol extract (EE), DF, and ethanol fraction (EF) exhibited considerable antifungal activity against Candida albicans. Moreover, extracts and fractions exhibited significant percentage of capture free radicals of 2,2-diphenyl-picrylhydrazyl (DPPH) when compared to the standard of ascorbic acid.

In vitro activity of hypnophilin from Lentinus strigosus: a potential prototype for Chagas disease and leishmaniasis chemotherapy.

Hypnophilin and panepoxydone, terpenoids isolated from Lentinus strigosus, have significant inhibitory activity on Trypanosoma cruzi trypanothione reductase (TR). Although they have similar TR inhibitory activity at 10 µg/mL (40.3 µM and 47.6 µM for hypnophilin and panepoxydone, respectively; ~100%), hypnophilin has a slightly greater inhibitory activity (~71%) on T. cruzi amastigote (AMA) growth in vitro as well as on in vitro phytohemagglutinin (PHA)-induced peripheral blood mononuclear (PBMC) proliferation (~70%) compared to panepoxydone (69% AMA inhibition and 91% PBMC inhibition). Hypnophilin and panepoxydone at 1.25 µg/mL had 67% inhibitory activity onLeishmania (Leishmania) amazonensis amastigote-like (AMA-like) growth in vitro. The panepoxydone activity was accompanied by a significant inhibitory effect on PHA-induced PBMC proliferation, suggesting a cytotoxic action. Moreover, incubation of human PBMC with panepoxydone reduced the percentage of CD16(+) and CD14(+) cells and down-regulated CD19(+), CD4(+) and CD8(+) cells, while hypnophilin did not alter any of the phenotypes analyzed. These data indicate that hypnophilin may be considered to be a prototype for the design of drugs for the chemotherapy of diseases caused by Trypanosomatidae.

In vitro activity of hypnophilin from Lentinus strigosus: a potential prototype for Chagas disease and leishmaniasis chemotherapy

Hypnophilin and panepoxydone, terpenoids isolated from Lentinus strigosus, have significant inhibitory activity onTrypanosoma cruzi trypanothione reductase (TR). Although they have similar TR inhibitory activity at 10 μg/mL (40.3 μM and 47.6 μM for hypnophilin and panepoxydone, respectively; ~100 percent), hypnophilin has a slightly greater inhibitory activity (~71 percent) on T. cruzi amastigote (AMA) growth in vitro as well as on in vitro phytohemagglutinin (PHA)-induced peripheral blood mononuclear (PBMC) proliferation (~70 percent) compared to panepoxydone (69 percent AMA inhibition and 91 percent PBMC inhibition). Hypnophilin and panepoxydone at 1.25 μg/mL had 67 percent inhibitory activity onLeishmania (Leishmania) amazonensis amastigote-like (AMA-like) growth in vitro. The panepoxydone activity was accompanied by a significant inhibitory effect on PHA-induced PBMC proliferation, suggesting a cytotoxic action. Moreover, incubation of human PBMC with panepoxydone reduced the percentage of CD16+ and CD14+ cells and down-regulated CD19+, CD4+ and CD8+ cells, while hypnophilin did not alter any of the phenotypes analyzed. These data indicate that hypnophilin may be considered to be a prototype for the design of drugs for the chemotherapy of diseases caused by Trypanosomatidae.

Antifungal activities of compounds isolated from Piper abutiloides Kunth.

Piperaceae is a family of tropical plants known to have antifungal, antibacterial, tumour-inhibitory, antiviral, antioxidant, molluscicidal and leishmanicidal activities. In this work, extracts and fractions from aerial parts of Piper abutiloides (Piperaceae), a traditional medicinal plant, were evaluated against the fungal species Candida albicans, C. parapsilosis, C. krusei, C. glabrata, C. tropicalis, Cryptococcus neoformans and Sporothrix schenckii. The results have shown that the antifungal activity of this plant can be concentrated in the hexanic fraction after partitioning its hydroalcoholic extract between hexane and 90% aqueous methanol. The chromatographic fractionation of the bioactive part was monitored with a bioautographic assay using C. glabrata, and allowed the isolation of three antifungal compounds: pseudodillapiol, eupomatenoid-6 and conocarpan. These compounds presented different potencies against the fungi tested, with the strongest effect being observed for eupomatenoid-6 against C. glabrata, which presented a minimal inhibitory concentration value of 0.3 microg spot(-1). Conocarpan showed antifungal activity without apparent cytotoxic effect on normal human lymphocytes, as assessed by the proliferation assay with human peripheral blood mononuclear cells stimulated with phytohaemaglutinin. This work reveals for the first time the occurrence of these compounds in P. abutiloides and justifies further studies to clarify their mechanisms of action.

Efeito do miriadenolídeo isolado de Alomia myriadenia (Asteraceae) sobre o tumor de Erlich ascítico no camundongo / Effect of myriadenolide isolated from Alomia myriadenia (Asteraceae) on Ehrlich tumor in its ascitic form

Estudou-se atividade antineoplásica de um produto natural isolado de Alomia myriadenia (miriadenolídeo) no modelo do tumor de Ehrlich em camundongos. Dezoito fêmeas de camundongo Swiss foram inoculadas com 2x10(7) células viáveis de tumor de Ehrlich via intraperitoneal (0,3ml) e posteriormente distribuídas aleatoriamente em três grupos que receberam: grupo I (controle) - 0,3ml de solução de Hanks; grupo II - 31µg/kg de miriadenolídeo; e grupo III - 139µg/kg de miriadenolídeo. No oitavo dia de experimento, foram realizados exames hematológicos e perfil protéico sérico eletroforético. Coletou-se todo o líquido ascítico para avaliação do volume, aparência, pH, contagem de células viáveis e inviáveis, realização de esfregaços para contagem de células claras e escuras, leucócitos e avaliação das regiões organizadoras de nucléolos argentafins (AgNORs). Foram realizados exames macro e microscópicos do baço, fígado e rins e aspirado o conteúdo da medula óssea dos fêmures direito e esquerdo de cada animal para avaliação da relação mielóide:eritróide. Não houve diferença significativa no volume, pH, contagem de células viáveis e inviáveis entre os três grupos estudados, observando-se valores de 17,6 x 10(4) células tumorais viáveis no grupo III, 27,7 x 10(4) no grupo II e 21,1 x 10(4) no grupo I. As AgNORs apresentaram-se pequenas, com distribuição difusa e incontáveis no grupo I, e em menor quantidade no grupo III. Os animais do grupo III apresentaram a menor concentração protéica total sérica (4,7g/dl) (P<0,05) quando comparados com os do grupo II (5,3g/dl) e do grupo I (5,1g/dl). Os valores de albumina foram semelhantes nos três grupos (2,6g/dl), e as globulinas totais foram maiores (P<0,05) no grupo II (2,71g/dl) quando comparadas com os valores médios do grupo III (2,11g/dl) e semelhantes ao grupo I (2,43g/dl). Não houve diferença entre alfa e beta globulinas entre os três grupos estudados, porém as gamaglobulinas foram maiores...

Antitumoral activity of a natural product of Alomia myriadenia (myriadenolide) in Ehrlich tumor in mice was studied. Eighteen Swiss female mice were intra-peritoneal inoculated 2x10(7) viable cells of Ehrlich Tumor (0.3ml) and randomly distributed in three groups receiving via intra-peritoneal on the 3rd and 5th day post-inoculation the following treatments: group I (control) - 0.3ml Hanks solution; group II: 31µg/kg myriadenolide; and group III: 139µg/kg myriadenolide. On the eighth day of the experiment blood profile and protein serum electrophoresis were performed. All ascitic liquid was collected to evaluate the volume and pH; to observe the aspect; to count viable and no viable cells, dark and clear cells, leukocytes and nucleolar organizer regions (NORs). Macro and microscopic exams were performed and bone marrow was aspirated from right and left femurs of each animal to evaluate myeloid:erythroid ratio. It was not observed difference in volume, pH, counts viable and no viable cells in the groups, although group III showed smaller number of viable tumoral cells (17.6 x 10(4)) when compared to the group II (27.7 x 10(4)) and group I (21.1 x 10(4)). The investigation of NORs to evaluate the proliferative capacity of tumoral cells after myriadenolide treatment showed that cells were smaller, uncountable and with diffuse distribution in group I. They were in lower quantity in group III. These results suggest that myriadenolide in dose 139µg/kg (group III) delay the tumoral growing and, probably, cell proliferation. The animals of group III showed lower value of total protein (4.7g/dl) (P<0.05) when compared to animals from group II (5.3g/dl) and group I (5.1g/dl). The values of albumin were similar in all groups (2.6g/dl) and total globulin was higher (P<0.05) in group II (2.71g/dl) when compared to mean values of group III (2.11g/dl) and similar to group I (2.43g/dl). The decrease of total protein in group III occurred...