In the present study, we evaluated the in vitro antiprotozoal activity of a guaianolide (11,13-dehydrocompressanolide) isolated from Tanacetum parthenium against Trypanosoma cruzi and investigated the possible combinational effect of guaianolide and benznidazole. The isolated compound was shown to be effective against T. cruzi, with IC(50) values of 18.1±0.8 and 66.6±1.3μM against the multiplicative epimastigote and amastigote forms, respectively. The best results were obtained against trypomastigotes, with an EC(50) of 5.7±0.7μM. The guaianolide presented no toxicity in LLCMK(2) cells (CC(50) of 93.5μM) and was 16.4-fold more selective for trypomastigotes. The study of the combinational effect of benznidazole and guaianolide revealed the presence of a synergistic effect against the epimastigote form and marginal additive effect against the trypomastigote form. Striking morphological changes were observed in epimastigotes treated with guaianolide, such as thinning and stretching of the cell body and flagellum and changes in the format of the cell body with apparent leakage of the cytoplasmic content in trypomastigote forms. The ultrastructural analysis of epimastigotes revealed the presence of membranes that involved organelles and formation of myelin-like figures. Flow cytometry revealed a cell volume reduction and decrease in mitochondrial membrane potential. However, no major changes in cell membrane integrity were found in the epimastigote form treated with guaianolide.

To discover new possible therapies for Chagas' disease, we evaluated against all Trypanosoma cruzi life stages the in vitro trypanocidal and synergistic activity of terpenes isolated from Copaifera oleoresins collected in the Amazon and investigated their possible mechanism of action. Seven acid diterpenes and one sesquiterpene were tested. Terpenes promoted changes in oxidative metabolism followed by autophagic processes in the parasite cell leading to selective death. Furthermore, they were more effective against replicative forms, in particular amastigotes. A synergistic effect occurred. Cytotoxicity to erythrocytes and nucleated cells was moderate. This is the first study showing synergic activity between two terpenes against T. cruzi. Combinations of natural compounds can show high activity and may lead to new alternative treatments in the future.

The in vitro activity of parthenolide against Leishmania amazonensis was investigated. Parthenolide is a sesquiterpene lactone purified from the hydroalcoholic extract of aerial parts of Tanacetum parthenium. This isolated compound was identified through spectral analyses by UV, infrared,(1)H and (13)C nuclear magnetic resonance imaging, DEPT (distortionless enhancement by polarization transfer), COSY (correlated spectroscopy), HMQC (heteronuclear multiple-quantum coherence), and electron spray ionization-mass spectrometry. Parthenolide showed significant activity against the promastigote form of L. amazonensis, with 50% inhibition of cell growth at a concentration of 0.37 microg/ml. For the intracellular amastigote form, parthenolide reduced by 50% the survival index of parasites in macrophages when it was used at 0.81 microg/ml. The purified compound showed no cytotoxic effects against J774G8 macrophages in culture and did not cause lysis in sheep blood when it was used at higher concentrations that inhibited promastigote forms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with gelatin as the substrate showed that the enzymatic activity of the enzyme cysteine protease increased following treatment of the promastigotes with the isolated compound. This finding was correlated with marked morphological changes induced by parthenolide, such as the appearance of structures similar to large lysosomes and intense exocytic activity in the region of the flagellar pocket, as seen by electron microscopy. These results provide new perspectives on the development of novel drugs with leishmanicidal activities obtained from natural products.

Leishmaniasis is a group of diseases with a large spectrum of clinical manifestations caused by protozoans of the genus Leishmania. Here we demonstrate the leishmanicidal activity of the essential oil of Ocimum gratissimum as well as its main constituent, eugenol. The eugenol-rich essential oil of O. gratissimum progressively inhibited Leishmania amazonensis growth at concentrations ranging from 100 to 1000 mug/ml. The IC(50)(sub-inhibitory concentration) of the essential oil for promastigotes and amastigotes were respectively 135 and 100 mug/ml and the IC(50) of eugenol was 80 mug/ml for promastigote forms. L. amazonensis exposed to essential oil at concentrations corresponding to IC(50) for promastigotes and for amastigotes underwent considerable ultrastructural alterations, as shown by transmission electron microscopy. Two or more nuclei or flagella were observed in 31% and 23.3% of treated amastigote and promastigote forms, respectively, suggesting interference in cell division. Considerable mitochondrial swelling was observed in essential oil-treated promastigotes and amastigotes, which had the inner mitochondrial membrane altered, with a significant increase in the number of cristae; in some amastigotes the mitochondrial matrix became less electron-dense. The minimum inhibitory concentration for both promastigotes and amastigotes was 150 mug/ml. Pretreatment of mouse peritoneal macrophages with 100 and 150 mug/ml essential oil reduced the indices of association between promastigotes and the macrophages, followed by increased in nitric oxide production by the infected macrophages. The essential oil showed no cytototoxic effects against mammalian cells. This set of results suggests that O. gratissimum essential oil and its compounds could be used as sources for new antileishmanial drugs.

The in vitro antiproliferative effects of 4 neolignans purified from the ethyl-acetate extract from leaves of Piper regnellii (MIQ.) C. DC. var. pallescens (C. DC.) YUNCK against Trypanosoma cruzi were investigated. These isolated compounds were identified through spectral analyses of UV, EI-MS,(1)H-,(13)C-NMR, H-H COSY, gNOE, HETCOR, and HMBC. The compounds eupomatenoid-5, eupomatenoid-6, and conocarpan showed considerable activity against epimastigote forms of T. cruzi, with 50% inhibition concentrations (IC(50)) of 7.0, 7.5, and 8.0 mug/ml respectively. After methylation, these compounds showed a lessened inhibitory activity to the growth of the protozoan, suggesting that loss of the hydroxyl group from their molecules reduces the activity. The compound eupomatenoid-3 showed lower activity than the hexane fraction. Eupomatenoid-5 was significantly more active than benznidazole, the antiparasitic drug of choice for treatment of Chagas' disease. The crude extract, hexane fraction, and eupomatenoid-5 caused no lysis in sheep blood at concentrations which inhibit the growth of epimastigote forms. The compound eupomatenoid-5 showed low cytotoxic effects against Vero cells. These results provide new perspectives on the development of novel drugs obtained from natural products with trypanocidal activity. However, the extracts and active compound isolated from P. regnellii var. pallescens should be further studied in animal models for in vivo efficacy.

ETHNOPHARMACOLOGICAL RELEVANCE: Copaiba oil has been used in folk medicine since the 19th century. The use of copaiba oils to treat leishmaniasis is cited in several ethnopharmacological studies. Nevertheless, the potential antileishmania of copaiba oils had not been studied. AIM OF THE STUDY: Eight different kinds of Brazilian copaiba oils were screened for antileishmanial activity. MATERIALS AND METHODS: The antiproliferative effect of promastigote and amastigote axenic were determined. To determine the survival index peritoneal macrophage were infected with promastigotes of Leishmania amazonensis and treated with copaiba oil. The cytotoxic effect of copaiba oil was assessed on macrophage strain J774G8 by assay of sulforhodamine B. RESULTS: Copaiba oils showed variable levels of activity against promastigote forms with IC(50) values in the range between 5 and 22mug/mL. The most active oil was that from Copaifera reticulata (collected in Pará State, Brazil) with IC(50) values of 5, 15, and 20mug/mL for promastigote, axenic amastigote and intracellular amastigote forms, respectively. Amphotericin B showed IC(50) of 0.058 and 0.231mug/mL against promastigote and amastigote forms, respectively. Cytotoxicity assay showed that this copaiba oil obtained from Copaifera reticulata showed low cytotoxicity against J774G8 macrophages. CONCLUSION: Copaiba oils showed significant activity against the parasite Leishmania amazonensis.

Development of effective strategies for treatment of candidiasis and other fungal diseases has posed a challenge, considering the increase in opportunistic fungal infections in HIV-positive and immunocompromised patients. The in vitro antifungal activity of essential oil from Ocimum gratissimum was investigated in order to evaluate its efficacy against Candida albicans, Candida krusei, Candida parapsilosis, and Candida tropicalis. Transmission and scanning electron microscopy and negative staining in light microscopy were performed to reveal the effects of the essential oil on the morphology of these yeasts. Determination of minimal inhibitory concentrations and time-kill curves demonstrated that the essential oil showed fungicidal activity against all of the Candida species studied. Analysis of the ultrastructure of the yeast cells revealed changes in the cell wall and in the morphology of some subcellular organelles. Bud formation in the yeasts was impaired in treated cells. The essential oil of O. gratissimum is a potential candidate as a phytotherapeutic agent in some fungal diseases and for the control of fungi in the environment.

Infections by protozoans of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which show renal and cardiac toxicity. As part of a search for new drugs against leishmaniasis, we evaluated the in vitro leishmanicidal activity of the (-) mammea A/BB. The compound (-) mammea A/BB is a coumarin-type mammea purified from a dichloromethane crude extract of leaves of Calophyllum brasiliense Cambess (Clusiaceae). The isolated compound was characterized using spectral analyses by UV, infrared, nuclear magnetic resonance of (1)H,(13)C, distortionless enhancement by polarization transfer, correlation spectroscopy, heteronuclear multiple bond correlation, and heteronuclear multiple quantum coherence. The compound (-) mammea A/BB showed significant activity against promastigote and amastigote forms of L. amazonensis, with IC(50)(50% inhibition concentration of cell growth) at a concentration of 3.0 and 0.88 mug/ml and IC(90)(90% inhibition concentration of cell growth) of 5.0 and 2.3 mug/ml, respectively. The coumarin (-) mammea A/BB showed no cytotoxicity against J774G8 macrophages in culture, when it was tested at high concentrations that inhibited promastigote forms. Electron microscopy studies revealed considerable ultrastructural changes when promastigote forms of L. amazonensis were treated with 3.0 mug/ml of the coumarin (-) mammea A/BB for 72 h. We observed significant changes such as mitochondrial swelling with concentric membranes in the mitochondrial matrix and intense exocytic activity in the region of the flagellar pocket. Other alterations included the appearance of binucleate cells and multiple cytoplasmic vacuolization. These results showed that (-) mammea A/BB is a potent growth inhibitor of L. amazonensis and caused important changes in the parasite's ultrastructure. This study provided new perspectives on the development of novel drugs with leishmanicidal activity obtained from natural products.

Chemical evaluation of the semi-purified fraction from the seeds of guaraná, Paullinia cupana H.B.K. var. sorbilis (Mart.) Ducke, yielded the following compounds: caffeine, catechin, epicatechin, ent-epicatechin, and procyanidins B(1), B(2), B(3), B(4), A(2), and C(1). Measurement of the antioxidant activity by reduction of the DPPH radical confirmed the anti-radical properties of the aqueous (AqE) and crude (EBPC) extracts and semi-purified (EPA and EPB) fractions. The EPA fraction showed radical-scavenging activity (RSA) and protected DPPH from discoloration at 5.23+/-0.08 (RSD%=1.49) mug/mL, and for the phosphomolybdenum complex showed a higher Relative Antioxidant Capacity (RAC) at 0.75+/-0.01 (1.75). The EPA fraction had a total polyphenolics content of 65.80%+/-0.62 (RSD%=0.93). The plant drug showed 5.47%+/- 0.19 (RSD%=3.51) and 6.19%+/- 0.08 (RSD%=1.29) for total polyphenolics and methylxanthines, respectively. In vitro assessment of the antibacterial potential of the Paullinia cupana extracts against Streptococcus mutans showed that these could be used in the prevention of bacterial dental plaque.

OBJECTIVES: The main objective of this work was to investigate the antifungal activity of a crude extract, fractions and subfractions from Stryphnodendron adstringens (Mart.) Coville, known as 'barbatimão'. METHODS: The growth inhibition by 'barbatimão' of 103 isolates of yeasts from vaginal fluid was determined using the broth microdilution method. In addition, the effect of the most active subfraction on cell surface hydrophobicity (CSH), germ-tube formation, budding, ultrastructure and phagocytosis of Candida albicans was analysed. Fluconazole and nystatin were used as reference drugs. The cytotoxicity of 'barbatimão' to Vero cells, macrophages and red blood cells was assessed. The most active subfraction was characterized by mass and (13)C NMR spectroscopy. RESULTS: Subfraction F2.4 had the best antifungal action at concentrations above 7.80 mg/L. Its action was similar to nystatin, and only slightly less effective than fluconazole. CSH and the capacity for adhering to Vero cells and a glass surface were lower in treated yeasts. In addition, the inhibition of formation of the germ tube, the increase in the number of buds and changes in the cell wall ultrastructure of C. albicans were also demonstrated.'Barbatimão' extracts showed low cytotoxicity to Vero cells, macrophages and red blood cells. Subfraction F2.4 is composed of proanthocyanidin polymers of prodelphinidin and prorobinetinidin units and gallic acid of molecular weight 2114 Da. CONCLUSIONS: The antifungal action of subfraction F2.4 on C. albicans can be attributed to condensed tannins. It is considered moderate antifungal activity. These properties of 'barbatimão' on the growth of C. albicans, putative virulence factors and its low cytotoxicity justify further studies to investigate the mechanisms of action and the possible development of a new antifungal agent.

Aeromonas isolates from tap water, mineral water, and artesian well water were investigated for their ability to produce different potential virulence factors or markers such as hemolysins, cytotoxins, phospholipase, DNase, hydrophobicity and their ability to adhere to epithelial cells and to abiotic surfaces. The susceptibility to antibiotics of Aeromonas isolates was also examined. Majority of the isolates displayed hemolytic activity against sheep erythrocytes, while only 7 of the 23 Aeromonas strains displayed DNase activity and 4 of the 23 Aeromonas strains tested were regarded as positive for phospholipase production. Most of the isolates showed cytotoxic activities in culture filtrate dilutions at titer of 1/8 or lower. No general relation between the strain isolated and the ability to interact with epithelial cells could be established. Using the bacterial adherence to hydrocarbons method, most of the strains were classified as highly hydrophilic. All five Aeromonas jandaei strains isolates, 9 of the 12 Aeromonas sp strains and four of the five Aeromonas hydrophila were multidrug resistant. The most active antimicrobial was ciprofloxacin (susceptible in 100% of the isolates), and the least active antibiotic was ampicillin (resistance in 92% of the isolates). The majority of the isolates tested were not killed by chlorine at 1.2 mg/l. Whether the high tolerance to chlorine of Aeromonas isolates can be linked to greater virulence is not know.

Several beta-carboline compounds were evaluated for in vitro trypanocidal activity against Trypanosoma cruzi and their potential toxic effects was also assessed. beta-Carboline derivative 4 showed good activity against epimastigote, trypomastigote, and amastigote forms of T. cruzi, with a dose-dependent inhibitory effect. It showed an IC(50) of 14.9muM against the epimastigote form and an EC(50) of 45muM and 33muM against trypomastigote and amastigote forms, respectively. Additionally, 4 was able to be active on mammalian cell-protozoan interaction, reducing the number of infected cells and the number of internalized parasites. The compound showed low cytotoxicity, with a selective index 31 times higher to the parasite than for mammalian cells. In human red-blood cells beta-Carboline 4 at 14.9muM not caused haemolysis. Observed at electron microscopy 4-treated epimastigotes showed abnormal swelling of the mitochondrion, a diffuse kinetoplast, and distortions of the parasite cell body. The present data support the potential effect of this class of compounds against T. cruzi and encourage further experiments in vitro to evaluate the action mechanism of this drug and also with in vivo models.