Estancia en Medellín, Colombia Febrero-Marzo 2016: Transferencia de Conocimientos PVCT15-53

Manejo de nuevas técnicas fluorescentes para la evaluación In Vivo de compuestos con actividad tripanocida y leishmanicida utilizando cepas transfectadas de Trypanosoma cruzi y Leishmania spp.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Genetic and toxinological divergence among populations of Tityus trivittatus Kraepelin, 1898 (Scorpiones: Buthidae) inhabiting Paraguay and Argentina

Autor de correspondencia: [email protected] by scorpions in genus Tityus is a public health problem in Tropical America. One of the most medically significant species is Tityus trivittatus, which is known to occur from southwest Brazil to central-northern and eastern Argentina. In this work, we studied the lethality, composition, antigenicity, and enzymatic activity of venom from a T. trivittatus population found further north in urban areas of eastern Paraguay, where it has caused serious envenomation of children. Our results indicate that the population is of medical importance as it produces a potently toxic venom with an LD50 around 1.19 mg/kg. Venom neutralization in preliminary mouse bioassays was complete when using Brazilian anti-T. serrulatus antivenom but only partial when using Argentinean anti-T. trivittatus antivenom. Venom competitive solid-phase enzyme immunoassays and immunoblotting from Argentinean and Paraguayan T. trivittatus populations indicated that antigenic differences exist across the species range. SDS-PAGE showed variations in type and relative amounts of venom proteins between T. trivitattus samples from Argentina and Paraguay. MALDI-TOF mass spectrometry indicated that while some sodium channel toxins are shared, including β-toxin Tt1g, others are population-specific. Proteolytic activity by zymography and peptide identification through nESI-MS/MS also point out that population-specific proteases may exist in T. trivitattus, which are postulated to be involved in the envenoming process. A time-calibrated molecular phylogeny of mitochondrial COI sequences revealed a significant (8.14%) genetic differentiation between the Argentinean and Paraguayan populations, which appeared to have diverged between the mid Miocene and early Pliocene. Altogether, toxinological and genetic evidence indicate that T. trivitattus populations from Paraguay and Argentina correspond to distinct, unique cryptic species, and suggest that further venom and taxonomic diversity exists in synanthropic southern South American Tityus than previously thought.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa de repatriación y radicación de investigadores del exteriorPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Programa Nacional de Incentivo a los Investigadore

Analysis of bioactivities and chemical composition of Ziziphus joazeiro Mart. using HPLC–DAD

AbstractThe aim of this study was to evaluate the chemical profile and antioxidant, antimicrobial and antiparasitic activities of the hydroalcoholic extract of the leaves of Ziziphus joazeiro Mart. (HELZJ). The antioxidant DPPH and FRAP assays and chemical profile were determined by colorimetric methods and HPLC/DAD. The antiparasitic, antibiotic and antibiotic-modifying activity were evaluated by microdilution assays. The HPLC–DAD assay showed the presence of mostly tannins and flavonoids, such as caffeic acid and quercetin. The levels of polyphenols and flavonoids were 183.136mg/g extract and 7.37mg/g extract, respectively. DPPH and FRAP showed low antioxidant activity for the extract. The antibacterial and antifungal activities were not of clinical relevance, showing MIC>1024μg/mL. However, synergism was observed between HELZJ and the antibiotics amikacin and gentamicin, which resulted in decreased bacterial drug resistance. EHFZJ showed low toxicity in fibroblasts in vitro, while antiparasitic results against Trypnosoma cruzi, Leishmania braziliensis and Leishmania infantum were not clinically relevant. Thus, our results indicate that Z. joazeiro Mart. (HELZJ) could be a source of plant-derived natural products that could lead to the development of promising new antibiotic compounds for infectious diseases

Exposición potencial a plaguicidas y evaluación de daño en el ADN a través del ensayo cometa y test de micronúcleos y nivel de colinesterasa plasmática en niños de población rural

El objetivo general del proyecto es determinar la prevalencia de daño al ADN (evaluado a través del Ensayo Cometa), presencia de micronúcleos (evaluado a través del test CBMN: cytikinesis-block micronucleu) la alteración de la colinesterasa plasmática y su relación a exposiciones a plaguicidas en dos grupos de niños menores de 10 años que habitan en zonas rurales.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Safety assessment and antioxidant activity of Lantana montevidensis leaves

Lantana camara, the widely studied species, and L. montevidensis, the less studied species of the genus Lantana are both used in traditional medicine for the same purpose (anti-asthma, anti-ulcer, anti-tumor, etc). However, little is known about the toxicity of L. montevidensis and there is limited information on its chemical constituents. Here, we investigated for the first time the genotoxicity and cytotoxicity of the ethanolic (EtOH) and aqueous extracts from the leaves of Lantana montevidensis in human leukocytes, as well as their ossible interaction with human erythrocyte membranes in vitro. The antioxidant activities of both extracts were also investigated in chemical and biological models. Treatment of leukocytes with EtOH or aqueous extracts (1-480 µg/mL) did not affect DNA damage index, but promoted cytotoxicity at higher concentrations (240-480 µg/mL). Both extracts did not modify the osmotic fragility of human erythrocytes. The extracts scavenged DPPH radical and prevented Fe2+-induced lipid peroxidation in rat’s brain and liver homogenates, and this was likely not attributed to Fe (II) chelation. The HPLC analysis of the extracts showed different amounts of polyphenolic compounds (isoquercitrin, gallic acid, catechin, ellagic acid, apigenin, kaempferol, caffeic acid, rutin, quercitrin, quercetin, chlorogenic acid, luteolin) that may have contributed to these effects. These results supported information on the functional use of L. mon-tevidensis in folk medicine

Engineering oral and parenteral amorphous amphotericin B formulations against experimental Trypanosoma cruzi infections

(Figure Presented) Chagas disease (CD) is a parasitic zoonosis endemic in most mainland countries of Central and South America affecting nearly 10 million people, with 100 million people at high risk of contracting the disease. Treatment is only effective if received at the early stages of the disease. Only two drugs (benznidazole and nifurtimox) have so far been marketed, and both share various limitations such as variable efficacy, many side effects, and long duration of treatment, thus reducing compliance. The in vitro and in vivo efficacy of poly-aggregated amphotericin B (AmB), encapsulated poly-aggregated AmB in albumin microspheres (AmB-AME), and dimeric AmB-sodium deoxycholate micelles (AmB-NaDC) was evaluated. Dimeric AmB-NaDC exhibited a promising selectivity index (SI = 3164) against amastigotes, which was much higher than those obtained for licensed drugs (benznidazole and nifurtimox). AmB-AME, but not AmB-NaDC, significantly reduced the parasitemia levels (3.6-fold) in comparison to the control group after parenteral administration at day 7 postinfection. However, the oral administration of AmB-NaDC (10-15 mg/kg/day for 10 days) resulted in a 75% reduction of parasitemia levels and prolonged the survival rate in 100% of the tested animals. Thus, the results presented here illustrate for the first time the oral efficacy of AmB in the treatment of trypanosomiasis. AmB-NaDC is an easily scalable, affordable formulation prepared from GRAS excipients, enabling treatment access worldwide, and therefore it can be regarded as a promising therapy for trypanosomiasis

AVALIAÇÃO DA ATIVIDADE TRIPANOCIDA, LEISHMANICIDA E CITOTÓXICA DO GERANIOL E CITRONELAL

Leishmanioses e tripanossomíases são doenças parasitárias globalmente difundidas com elevado índice de mortalidade e morbidade. O arsenal terapêutico é restrito e de efeitos colaterais indesejáveis. No entanto, a biodiversidade de plantas brasileiras representa rica fonte de novos compostos com potencial antiparasitário. O geraniol é um monoterpeno encontrado em plantas como Cymbopogon winteranus e Cymbopogon martinii. Ocitronelal é um fitoconstituínte monoterpenóide de Eucalyptus citriodora e Cymbopogon citratus. O objetivo deste estudo foi avaliar a atividade antiparasitária in vitro desses terpenoides isolados contra formas epimastigotas e promastigotas de Trypanosoma cruzi e Leishmania. brasiliensis, bem como verificar sua citotoxicidade em células de mamíferos. As substâncias foram testadas nas concentrações de 50 e 100 µg/mL, contudo, geraniol demonstrou baixa atividade contra T. cruzi, nestas concentrações, não demonstrando efeito contra promastigotas de L. braziliensis e revelando elevada citotoxicidade sobre células de mamíferos. O citronelal apresentou atividade moderada antipromastigota revelando altos índices de citotoxicidade.(http://dx.doi.org/10.14295/cad.cult.cienc.v13i2.841)

Multi-anti-parasitic activity of arylidene ketones and thiazolidene hydrazines against trypanosoma cruzi and Leishmania spp.

A series of fifty arylideneketones and thiazolidenehydrazines was evaluated against Leishmania infantum and Leishmania braziliensis. Furthermore, new simplified thiazolidenehydrazine derivatives were evaluated against Trypanosoma cruzi. The cytotoxicity of the active compounds on non-infected fibroblasts or macrophages was established in vitro to evaluate the selectivity of their anti-parasitic effects. Seven thiazolidenehydrazine derivatives and ten arylideneketones had good activity against the three parasites. The IC50 values for T. cruzi and Leishmania spp. ranged from 90 nM–25 μM. Eight compounds had multi-trypanocidal activity against T. cruzi and Leishmania spp. (the etiological agents of cutaneous and visceral forms). The selectivity of these active compounds was better than the three reference drugs: benznidazole, glucantime and miltefosine. They also had low toxicity when tested in vivo on zebrafish. Trying to understand the mechanism of action of these compounds, two possible molecular targets were investigated: triosephosphate isomerase and cruzipain. We also used a molecular stripping approach to elucidate the minimal structural requirements for their anti-T. cruzi activity

La salud de los ecosistemas, transmisión de enfermedades y alteración del hábitat: Importancia para la salud global y la conservación de la biodiversidad

El objetivo del trabajo fue examinar los efectos de la degradación del hábitat y del impacto antrópico sobre la salud de las poblaciones de mamíferos silvestres y los patrones de transmisión inter-especifica de parásitos entre animales silvestres, domésticos y humanos.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

Avaliação da citotoxicidade e atividade leishmanicida e tripanocida de extratos de Passiflora cincinnata Mast L.

A doença de Chagas e a leishmaniose são doenças que prevalecem em países pobres. Os fármacos disponíveis para o tratamento dessas doenças são altamente tóxicos, sendo este um dos motivos que dificulta à adesão terapêutica e, assim, levando à busca por novas drogas eficazes e seguras para seus tratamentos. A pesquisa utilizando produtos naturais tem se mostrado uma alternativa na procura de novos compostos com potencial clínico-terapêutico. O gênero Passiflora possui as seguintes atividades farmacológicas centrais como calmantes, sedativas, ansiolíticas e indutor do sono e atividades antiparasitarias. A Passiflora cincinnata possui ampla distribuição pelo Brasil sendo popularmente utilizada para distúrbios de sono. Neste estudo avaliamos sua atividade antiparasitária contra Leishmania brasiliensis, Leishmania infantum e Trypanosoma cruzi, bem como sua citotoxicidade em fibroblastos. Foram testados extratos hidroalcoólicos obtidos das folhas, casca, sementes e caule em diferentes concentrações. Os extratos das folhas, casca e sementes não foram eficazes contra L. brasiliensis e T. cruzi, porém, o extrato do caule promoveu uma inibição de 29,12 % contra T. cruzi numa concentração de 500 µg/mL, entretanto o extrato da casca de P. cincinnata foi o que apresentou a melhor atividade contra as formas parasitárias de L. infantum, causando um percentual de morte >20 % nas concentrações de 250 a 1000 µg/mL. Referente à toxicidade, o extrato das folhas foi o que apresentou maior citotoxicidade, quando comparado com os demais, causando a mortalidade de 68,63 % dos fibroblastos numa concentração de 1000 µg/mL. A baixa citotoxicidade revelada abre espaço para novos estudos biológicos