In vitro efficacy of isoflavonoids and terpenes against Leishmania (Leishmania) infantum and L. amazonensis.

The main form of control of leishmaniasis is the treatment, however various side effects and poor efficacy are associated with presently available drugs. The investigation of bioactive natural products for new antileishmanial drugs is a valid approach. The present study reports the in vitro efficacy of natural isoflavonoids and terpenes against Leishmania infantum and L. amazonensis and their cytotoxicity against HepG2 cells. L. infantum and L. amazonensis promastigotes were exposed to the terpenes kaurenoic acid, xylopic acid, and (-)-α-bisabolol and to the isoflavonoids (-)-duartin and (3R)-claussequinone for antileishmanial activity and to cytotoxicity to HepG2 cells. The most effective substance against both L. infantum and L. amazonensis species was (3R)-claussequinone (IC50 = 3.21 µg/mL and 2.47 µg/mL, respectively) that disclosed low cytotoxicity against HepG2 cells (CC50 = 387.79 µg/mL). The efficacy of (3R)-claussequinone against intracellular amastigotes of L. infantum and the externalization of phosphatidylserine in promastigotes of this isoflavanoid were investigated by infection of Raw 264.7 macrophages and marking with Annexin V-FITC and propidium Iodide for flow cytometry analysis. The results for amastigotes showed that (3R)-claussequinone was able to reduce the rate of infection with IC50 = 4.61 µg/mL and did not alter the externalization of phosphatidylserine. In conclusion it is presently reported, for the first time, the striking antileishmanial activity of (3R)-claussequinone against L. infantum and L. amazonensis associated to low cytotoxicity. Furthermore, these results suggest that (3R)-claussequinone is a new hit aiming to develop new therapeutic alternatives.

Conhecer para prevenir: complementação do conhecimento dos alunos do ensino fundamental sobre microbiologia e parasitologia em três escolas de Uberlândia-MG / Know to prevent: complementation of the knowledge of the students of fundamental education on microbiology and parasitology in three schools of Uberlândia-MG

O conhecimento sobre microbiologia e parasitologia é considerado abstrato, pois muitos agentes causadores de doenças não são vistos a olho nu, o que distancia os alunos da realidade. Assim, nossos objetivos foram promover ações educativas por meio de ferramentas didáticas lúdicas que possibilitassem a complementação do aprendizado dos alunos frente aos diferentes grupos de microorganismos e parasitos e das ações de profilaxia relacionadas aos mesmos, e avaliar se ao final eles tinham condições de discriminar os grupos e relacionar com as doenças e as formas de profilaxia. Para tanto, foram feitas entrevistas junto aos professores para levantamento das possíveis atividades a serem desenvolvidas. A ação foi definida e então dividida em três momentos (aula expositiva, jogo didático e mostra científica) realizados entre agosto e novembro de 2018, atingindo aproximadamente 350 alunos, de oitavos e nonos anos, de três escolas públicas da zona urbana e rural da cidade de Uberlândia-MG. Para avaliar o impacto da ação foi feita uma análise comparativa de questionários aplicados antes (pré-intervenção) e após a ação (pós-intervenção). O percentual das respostas corretas nos questionários pós-intervenção aumentou em duas escolas (p>0,005). Quanto à análise por questões, as menores porcentagens de acertos foram observadas em perguntas relacionadas à distinção entre doenças bacterianas e virais, o reconhecimento dos sintomas e a associação das formas de transmissão com a profilaxia. Assim, este estudo reforça a importância da educação em saúde para que os alunos se mobilizem frente ao combate das doenças.(AU)

The knowledge about microbiology and parasitology is considered abstract since causative agents of diseases cannot be seen with the naked eye, leading to students' detachment from reality. Therefore, this work aimed to promote educational actions through playful tools that could complement students' learning regarding the different groups of microorganisms and parasites and the prophylactic measures related to them. Furthermore, at the end of the actions it was evaluated if the students were able to discriminate the groups of microorganisms and relate them to the diseases they cause and the different forms of prophylaxis. To this end, interviews were conducted with teachers to survey the possible activities that could be used. The action was defined and then divided into three moments (expository class, didactic game and scientific show) held between August and November 2018, reaching approximately 350 students, from the eighth and ninth years, from three public schools in the urban and rural area of the city oftUberlândia-MG. To assess the impact of the action, a comparative analysis of questionnaires was applied before (pre-intervention) and after the action (post-intervention). The percentage of correct answers in the questionnaires post-intervention increased in two schools (p>0,005). Regarding the analysis by questions, the lowest percentages of correct answers were observed in questions related to the distinction between bacterial and viral diseases, the recognition of the symptoms and the association of transmission ways with prophylaxis. Thus, this study reinforces the importance of health education for students to mobilize in the fight against diseases.(AU)

Efficacy of lapachol on treatment of cutaneous and visceral leishmaniasis.

Leishmaniasis is one of the most important neglected diseases worldwide. It is a life-threatening disease and causes significant morbidity, long-term disability, and early death. Treatment involves disease control or use of intervention measures, although the currently used drugs require long-lasting therapy, and display toxicity and reduced efficacy. The use of natural products isolated from plants, such as lapachol, an abundant naphthoquinone naturally occurring in South American Handroanthus species (Tabebuia, Bignoniaceae), is a promising option for the treatment of leishmaniasis. In this study, we investigated the leishmanicidal activity of lapachol in vitro and in vivo against Leishmania infantum and L. amazonensis, causative agents of visceral and cutaneous leishmaniasis, respectively. Low cytotoxicity in HepG2 cells (3405.8 ±â€¯261.33 µM), good anti-Leishmania activity, and favorable selectivity indexes (SI) against promastigotes of both L. amazonensis (IC50 = 79.84 ±â€¯9.10 µM, SI = 42.65) and L. infantum (IC50 = 135.79 ±â€¯33.04 µM, SI = 25.08) were observed. Furthermore, anti-Leishmania activity assays performed on intracellular amastigotes showed good activity for lapachol (IC50 = 191.95 µM for L. amazonensis and 171.26 µM for L. infantum). Flow cytometric analysis demonstrated that the cytotoxic effect of lapachol in Leishmania promastigotes was caused by apoptosis-like death. Interestingly, the in vitro leishmanicidal effect of lapachol was confirmed in vivo in murine models of visceral and cutaneous leishmaniasis, as lapachol (25 mg/kg oral route for 24 h over 10 days) was able to significantly reduce the parasitic load in skin lesions, liver, and spleen, similar to amphotericin B, the reference drug. These results reinforce the therapeutic potential of lapachol, which warrants further investigations as an anti-leishmaniasis therapeutic.

In vitro antileishmanial activity of leaf and stem extracts of seven Brazilian plant species.

ETHNOPHARMACOLOGICAL RELEVANCE: Leishmaniasis is a parasitic disease that affects people all over the world. The number of cases of leishmaniasis is increasing and the drugs used for its treatment are toxic and not always effective. The recognition of the global nature of this disease and its direct or indirect effects on health economics and actions focuses attention on the development of new therapeutic options. In Brazil, this parasitic disease is endemic in many regions. The plants used by the population against leishmaniasis can be good starting points in the search of new lead compounds for antileishmanial drugs. AIM OF THE STUDY: The aim of the present study was to investigate the antileishmanial activity of extracts from leaves and stems of seven Brazilian plant species used by the population to treat leishmaniasis, and symptoms that might be related to Leishmania infections. MATERIALS AND METHODS: Twenty two extracts from seven plants belonging to five different botanical families were prepared by different methods and evaluated for their effect on the viability of promastigote forms of Leishmania infantum (MHOM/BR/1967/BH46) using the resazurin-based colorimetric assay. The extracts were considered active when they inhibited the growth of promastigotes in a percentage greater than or equal to 50% at 100 and 200 µg/mL. The active samples were further investigated to determine IC50, CC50 and SI values against promastigote forms of L. infantum. The active and non-cytotoxic extracts (SI> 10) were evaluated against amastigote forms of L. infantum. In addition, the active extracts against the amastigote forms were analyzed by TLC and HPLC, while the EtOAc extract of stems from Aspidosperma tomentosum was also evaluated by GC/MS. RESULTS: Among the twenty two extracts evaluated, two were considered active against L. infantum. The EtOH extract of leaves from Dyospiros hispida (IC50 55.48 ±â€¯2.77 µg/mL and IC50 80.63 ±â€¯13.17 µg/mL, respectively) and the EtOAc extract of stems from Aspidosperma tomentosum (IC50 9.70 ±â€¯2.82 µg/mL and IC50 15.88 ±â€¯1.53 µg/mL, respectively) inhibited significantly the growth of promastigote and amastigote forms of L. infantum. Some extracts, although active in the initial screening, were considered toxic since the SI was lower than 10. In TLC and HPLC analysis the leaf extract of Dyospiros hispida showed the presence of anthraquinones, terpenes and saponins, and in the EtOAc extract of stems from Aspidosperma tomentosum alkaloids and flavonoids were detected. In addition, in the latter extract the indole alkaloids uleine and dasycarpidone could be identified by GC/MS. CONCLUSIONS: The ethnopharmacological data of Aspidosperma tomentosum and Dyospiros hispida in part support the results found in the biological models used. Extracts of Aspidosperma tomentosum and Dyospiros hispida presented promising results against L. infantum.