Antileishmanial activity of new thiophene-indole hybrids: Design, synthesis, biological and cytotoxic evaluation, and chemometric studies.

In the present work, thirty-two hybrid compounds containing cycloalka[b]thiophene and indole moieties (TN5, TN5 1-7, TN6, TN6 1-7, TN7, TN7 1-7, TN8, TN8 1-7) were designed, synthesized and evaluated for their cytotoxic and antileishmanial activity against Leishmania amazonensis promastigotes. More than half of the compounds (18 compounds) exhibited significant antileishmanial activity (IC50 lower than 10.0µg/L), showing better performance than the reference drugs (tri- and penta-valent antimonials). The most active compounds were TN8-7, TN6-1 and TN7 with respective IC50 values of 2.1, 2.3 and 3.2µg/mL. Demonstrating that all of the compounds were less toxic than the reference drugs, even at the highest evaluated concentration (400µg/mL), no compound tested presented human erythrocyte cytotoxicity. Compound TN8-7's effectiveness against a trivalent antimony-resistant culture was demonstrated. It was observed that TN8-7's antileishmanial activity is associated with DNA fragmentation of L. amazonensis promastigotes. Chemometric studies (CPCA, PCA, and PLS) highlight intrinsic solubility/lipophilicity, and compound size and shape as closely related to activity. Our results suggest that hybrid cycloalka[b]thiophene-indole derivatives may be considered as lead compounds for further development of new drugs for the treatment of leishmaniasis.

Neolignan Licarin A presents effect against Leishmania (Leishmania) major associated with immunomodulation in vitro.

Leishmaniasis' treatment is based mostly on pentavalent antimonials or amphotericin B long-term administration, expensive drugs associated with severe side effects. Considering these aforementioned, the search for alternative effective and safe leishmaniasis treatments is a necessity. This work evaluated a neolignan, licarin A anti-leishmanial activity chemically synthesized by our study group. It was observed that licarin A effectively inhibited Leishmania (Leishmania) major promastigotes (IC50 of 9.59 ± 0.94 µg/mL) growth, by inducing in these parasites genomic DNA fragmentation in a typical death pattern by apoptosis. Additionally, the neolignan proved to be even more active against intracellular amastigotes of the parasite (EC50 of 4.71 ± 0.29 µg/mL), and significantly more effective than meglumine antimoniate (EC50 of 216.2 ± 76.7 µg/mL) used as reference drug. The antiamastigote activity is associated with an immunomodulatory activity, since treatment with licarin A of the infected macrophages induced a decrease in the interleukin (IL)-6 and IL-10 production. This study demonstrates for the first time the antileishmanial activity of licarin A and suggests that the compound may be a promising in the development of a new leishmanicidal agent.

Antibacterial and antiparasitic effects of Bothropoides lutzi venom.

The therapeutic potential of toxins has aroused great interest in the scientific community. Microbial resistance is a serious current public health problem, in part because of the wide use of antimicrobial drugs. Furthermore, there are several problems in the treatment of parasitic diseases such as leishmaniosis and Chagas' disease, including the low efficacy in some clinical phases of the diseases and the loss of effectiveness of benzonidazole in the chronic phase of Chagas' disease. In this context, the aim of this work was to study the antimicrobial and antiparasitic effects of Bothropoides lutzi total venom (BltTV). The venom exerted an antibacterial effect on S. aureus, with MIC=MLC=200 microg/mL. The inhibitory effects of BltTV on promastigote forms of Leishmania amazonensis and L. chagasi were assessed by counting of viable cells after incubation with BltTV. IC50 values of 234.6 microg/mL and 61.2 microg/mL, were obtained, respectively. Furthermore, the venom repressed epimastigote forms of Trypanosoma cruzi growth. Finally, BltTV was verified to affect murine peritoneal macrophages, causing a cytotoxic effect at the highest concentrations (100 and 50 microg/mL). In conclusion, Bothropoides lutzi venom demonstrated antibacterial and antiparasite effects, suggesting that the venom contains some substance(s) of therapeutic value.

Synthesis, evaluation against Leishmania amazonensis and cytotoxicity assays in macrophages of sixteen new congeners Morita-Baylis-Hillman adducts.

We report the design, synthesis, in vitro evaluation against Leishmania amazonensis (IC(50)), cytotoxicity assays in macrophages (CC(50)), and selectivity index (SICC(50)/IC(50)) of sixteen new congeners aromatic Morita-Baylis-Hillman adducts 1-16. The 1-16 were prepared in good to excellent yields (58%-97%) from the "one pot" Morita-Baylis-Hillman Reaction between the aldehydes 29-36 and the acrylates 27 or 28 under DABCO as promoter. The MBHA 2-[Hydroxy(2-nitrophenyl)propyl] propanoate (1, IC(50) = 7.52 µg/mL or 28.38 µM; CC(50) = 35.77 µg/mL or 134.98 µM; SI = 4.75) and 2-[Hydroxy(2-nitrophenyl)hydroxyethyl] propanoate (9, IC(50) = 5.48 µg/mL or 20.52 µM; CC(50) = 29.81 µg/mL or 111.64c µM and, SI = 5.43) were the most effective and safe evaluated compounds.

Design, synthesis and antileishmanial in vitro activity of new series of chalcones-like compounds: a molecular hybridization approach.

The chalcone-like series 1a-1g was efficiently synthesized from Morita-Baylis-Hillman reaction (52-74% yields). Compounds 1a-1g were designed by molecular hybridization based on the anti-inflammatory drug methyl salicylate (3) and the antileishmanial moiety of the Morita-Baylis-Hillman adducts 2a-2g. The 1a-1g compounds were much more actives than precursor series 2a-2g, for example, IC(50)=7.65 µM on Leishmania amazonensis and 10.14 µM on Leishmania chagasi (compound 1c) when compared to IC(50)=50.08 µM on L. amazonensis and 82.29 µM on L. chagasi (compound 2c). The IC(50) values of compound 3 (228.49 µM on L. amazonensis and 261.45 µM on L. chagasi) and acryloyl salicylate 4 (108.50 µM on L. amazonensis and 118.83 µM on L. chagasi) were determined here, by the first time, on Leishmania.

Morphological and physiological changes in Leishmania promastigotes induced by yangambin, a lignan obtained from Ocotea duckei.

We have previously demonstrated that yangambin, a lignan obtained from Ocotea duckei Vattimo (Lauraceae), shows antileishmanial activity against promastigote forms of Leishmania chagasi and Leishmania amazonensis. The aim of this study was to determine the in vitro effects of yangambin against these parasites using electron and confocal microscopy. L. chagasi and L. amazonensis promastigotes were incubated respectively with 50 µg/mL and 65 µg/mL of pure yangambin and stained with acridine orange. Treated-parasites showed significant alterations in fluorescence emission pattern and cell morphology when compared with control cells, including the appearance of abnormal round-shaped cells, loss of cell motility, nuclear pyknosis, cytoplasm acidification and increased number of acidic vesicular organelles (AVOs), suggesting important physiological changes. Ultrastructural analysis of treated-promatigotes showed characteristics of cell death by apoptosis as well as by autophagy. The presence of parasites exhibiting multiples nuclei suggests that yangambin may also affect the microtubule dynamic in both Leishmania species. Taken together our results show that yangambin is a promising agent against Leishmania.

Efficient synthesis of 16 aromatic Morita-Baylis-Hillman adducts: Biological evaluation on Leishmania amazonensis and Leishmania chagasi.

Sixteen aromatic Morita-Baylis-Hillman adducts (MBHA) 1-16 were efficiently synthesized in a one step Morita-Baylis-Hillman reaction (MBHR) involving commercial aldehydes with methyl acrylate or acrylonitrile (81-100% yields) without the formation of side products on DABCO catalysis and at low temperature (0°C). The toxicities of these compounds were assessed against promastigote form of Leishmania amazonensis and Leishmania chagasi. The low synthetic cost of these MBHA, green synthetic protocols, easy one-step synthesis from commercially available and cheap reagents as well as the very good antileishmanial activity obtained for 14 and 16 (IC50 values of 6.88µgmL⁻¹ and 11.06µgmL⁻¹ respectively on L. amazonensis; 9.58µgmL⁻¹ and 14.34µgmL⁻¹ respectively on L. chagasi) indicates that these MBHA can be a novel and promising class of anti-parasitic compounds.

Anti-mitotic activity towards sea urchin eggs of dichloromethane fraction obtained from Allamanda schottii Pohl (Apocynaceae) / Atividade anti-mitótica da fração diclorometano obtida de Allamanda schottii Pohl (Apocynaceae) sobre ovos do ouriço do mar

Allamanda (Apocynaceae) is a genus of climbing shrubs known for producing compounds with a range of biological activities. Previous works have shown the anti-proliferative effect of the ethanolic extract of Allamanda schottii on leukemic cells. The present work was conducted to evaluate the effects of dichloromethane fraction, obtained from Allamanda schottii, on sea urchin Echinometra lucunter eggs, as a multicellular model for evaluating anti-tumor activity. Our results show an inhibition of sea urchin development in a dose-dependent manner in the presence of dichloromethane fraction. The IC50 values for first and third cleavage and blastulae stage were 103.7 µg/mL, 33.1 µg/mL and 10.2 µg/mL, respectively. These results also demonstrate the cumulative effect of this fraction on sea urchin embryos. In the present work, the expressive anti-mitotic activity of dichloromethane fraction towards sea urchin eggs, a multicellular model, reinforces the anti-tumor potential of the Allamanda schotti.

Allamanda (Apocynacea) é um gênero de arbustos escandentes conhecido por produzir compostos com várias atividades biológicas. Trabalhos anteriores têm mostrado um efeito anti-proliferativo do extrato etanólico de Allamanda schottii sobre células leucêmicas. O presente trabalho foi realizado para avaliar o efeito da fração diclorometano, obtida de Allamanda schotti, sobre os ovos de ouriço-do-mar de Echinometra lucunter, como um modelo multicelular para estudar atividade anti-tumoral. Nossos resultados mostram uma inibição do desenvolvimento dos ovos de uma maneira dose-dependente na presença da fração diclorometano. Os valores de IC50 para a primeira e terceira clivagem e para o estágio de blástula foram de 103,7 µg/mL, 33.1 µg/mL e 10,2 µg/mL, respectivamente. Estes resultados também demonstram um efeito acumulativo da fração sobre os embriões do ouriço-do-mar. No presente trabalho, esta expressiva atividade anti-mitótica da fração diclorometano sobre o desenvolvimento embrionário do ouriço-do-mar, um modelo multicelular, reforça o potencial antitumoral de Allamanda schotti.

Improved synthesis of seven aromatic Baylis-Hillman adducts (BHA): evaluation against Artemia salina Leach. and Leishmania chagasi.

We described a very efficient procedure to prepare seven aromatic compounds (1-7), a new class of antileishmanial substances, through Baylis-Hillman reaction (BHR). With one, all the Baylis-Hillman adducts were prepared in quantitative yields by reaction of the corresponding aromatic aldehydes in acrylonitrile at 0 degrees C in only 10-40min reaction time. We present our results about the toxicities of these compounds evaluated on the microcrustaceous Artemia salina Leach. and against promastigote Leishmania chagasi. All substances evaluated in this work have showed high bioactivity. The 3-hydroxy-2-methylene-3-(4-bromopheny)propanenitrile (4) (LC(50)=30.9 microg/mL on A. salina; IC(50)=25.2 microM on L. chagasi) was the most active compound evaluated on A. salina Leach. and on promastigote L. chagasi. The 2-[hydroxy(pyridin-4-yl)methyl]acrylonitrile (7) (LC(50)=30.9 microg/mL on A. salina Leach.; IC(50)=4.8 microg/mL on L. chagasi) was also a very active substance evaluated in this work on promastigote L. chagasi.

Yangambin cytotoxicity: a pharmacologically active lignan obtained from Ocotea duckei vattimo (Lauraceae).

The in vitro cytotoxic potential of yangambin was evaluated. Yangambin is a pharmacologically active furofuran lignan obtained from the leaves of Ocotea duckei. It is the major compound from the lignoids fraction. Yangambin presented low cytotoxicity in all in vitro models analyzed. Its cytotoxicity to murine macrophages was measured by the Trypan blue dye exclusion test and MTT reduction assay, resulting in high CC50 values of 187.0 microg/mL (383.3 microM) and 246.7 microg/mL (504.3 microM), respectively. The difference obtained in the inhibitory concentrations aforementioned can be explained, at least in part, by the different principles of the methods. While the MTT reduction assay evaluates the ability of yangambin to inhibit the activity of the mitochondrial enzyme succinate dehydrogenase, the Trypan blue dye exclusion test evaluates possible damages to the integrity of the cytoplasmic membrane which result in cell death. The capacity of yangambin to inhibit the sea urchin embryonic development showed that it has low antimitotic and teratogenic potential, once continued exposure of embryos to concentrations up to 500 microg/mL (1.025 microM) did not result in an inhibitory effect on the first egg cleavages. Such low in vitro cytotoxicity is correlated with the low acute toxicity previously studied. All these data, together with the various therapeutic properties of yangambin, make this lignan a promising one for a new drug.

Análise da perspectiva ciência, tecnologia e sociedade em materiais didáticos / Analyzing the perspective science, technology and society in didactic materials

Esse trabalho propõe a análise da produção parcial de materiais didáticos para o ensino de ciências na perspectiva Ciência, Tecnologia e Sociedade (CTS), elaborados por um grupo de professores e estudantes universitários, bem como professores de ciências da rede pública de ensino. Os materiais foram desenvolvidos no âmbito do projeto “Instrumentação para o ensino interdisciplinar das Ciências daNatureza e da Matemática”, pelo Centro de Divulgação Científica e Cultural da Universidade de São Paulo em parceria com a Universidade Federal de São Carlos. Como resultados principais, os materiais didáticos selecionados das áreas de Biologia e Química (kits experimentais) demonstram uma preocupação com a contextualização dos conhecimentos científicos e tecnológicos, uso de recursos locais e estabelecimento de relações globais, a construção de ações em que os estudantes têm um papel ativo para a tomada de decisões e resolução de problemas, sendo o papel do professor o de facilitador da aprendizagem.

Crude ethanolic extract, lignoid fraction and yangambin from Ocotea duckei (Lauraceae) show antileishmanial activity.

Crude ethanolic extract, lignoid fraction and the purified compound yangambin were obtained from Ocotea duckei (Lauraceae) and their antileishmanial activity was tested against promastigote forms of Leishmania chagasi and Leishmania amazonensis cultivated in Schneider medium, supplemented with 20% of fetal bovine serum. All substances presented antileishmanial activity with IC50 values of 135.7 microg/mL for the crude ethanolic extract, 26.5 microg/mL for the lignoid fraction and 49.0 microg/mL for yangambin on L. chagasi. For L. amazonensis the IC50 values were 143.7 microg/mL, 48.2 microg/mL and 64.9 microg/mL for the crude ethanolic extract, the lignoid fraction, and the purified compound yangambin, respectively. The crude ethanolic extract, lignoid fraction, and yangambin caused an inhibition higher than Glucantime, a reference drug used for the treatment of leishmaniasis.