Perfil fitoquímico e ensaio microbiológico dos extratos da entrecasca de Maytenus rigida Mart. (Celastraceae) / Phytochemistry and microbiological assay of the bark extracts of Maytenus rigida Mart. (Celastraceae)

Maytenus rigida Mart (Celastraceae), conhecida por "Bom-homem", "Bom-nome", "Cabelo-de-negro", "Casca-grossa" e "Pau-de-colher", é uma arvore de pequeno porte. A entrecasca do caule é empregada popularmente no Nordeste do Brasil no tratamento das dores em geral, infecções e inflamações. O presente trabalho avaliou tanto o perfil fitoquímico de M. rigida por meio de um roteiro analítico, quanto à atividade antibiótica dos extratos pelo método de Kirby-Bauer modificado. Os resultados demonstraram que os extratos etanólico, aquoso, clorofórmico, acetato de etila e hidroalcoólico de M. rigida apresentam atividade antibacteriana contra Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus, enquanto que a fração hexânica não exibe qualquer atividade. Catequinas, quinonas, esteróides, triterpenos, saponinas, flavonóides e compostos fenólicos foram detectados na análise fitoquímica.

Maynetus rigida Mart (Celastraceae), known as "Bom-homem", "Bom-nome", "Cabelo-de-negro", "Casca-grossa" and "Pau-de-colher", is a small tree. The stem bark is used by the population in the northeast of Brazil to treat aches, infections and inflammations in general. The present work evaluated both the phytochemistry of M. rigida Mart by an analytical routine, and the antimicrobial activity of the bark extracts by the Kirby-Bauer modified method. Our results showed the aqueous, methanol, chloroform, ethyl acetate and hydroalcoolic extracts of M. rigida Mart has antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, while the hexane extract does not have any activity. Catechins, quinones, steroids, triterpenes, saponins, flavonoids and phenolic compounds were detected by the phytochemical analysis.

Resistance of Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis to nitric oxide correlates with disease severity in Tegumentary Leishmaniasis.

BACKGROUND: Nitric oxide (NO*) plays a pivotal role as a leishmanicidal agent in mouse macrophages. NO* resistant Escherichia coli and Mycobacterium tuberculosis have been associated with a severe outcome of these diseases. METHODS: In this study we evaluated the in vitro toxicity of nitric oxide for the promastigote stages of Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis parasites, and the infectivity of the amastigote stage for human macrophages. Parasites were isolated from patients with cutaneous, mucosal or disseminated leishmaniasis, and NO* resistance was correlated with clinical presentation. RESULTS: Seventeen isolates of L. (L.) amazonensis or L. (V.) braziliensis promastigotes were killed by up to 8 mM of more of NaNO2 (pH 5.0) and therefore were defined as nitric oxide-susceptible. In contrast, eleven isolates that survived exposure to 16 mM NaNO2 were defined as nitric oxide-resistant. Patients infected with nitric oxide-resistant Leishmania had significantly larger lesions than patients infected with nitric oxide-susceptible isolates. Furthermore, nitric oxide-resistant L. (L.) amazonensis and L. (V.) braziliensis multiplied significantly better in human macrophages than nitric oxide-susceptible isolates. CONCLUSION: These data suggest that nitric oxide-resistance of Leishmania isolates confers a survival benefit for the parasites inside the macrophage, and possibly exacerbates the clinical course of human leishmaniasis.

Differential effects of antigens from L. braziliensis isolates from disseminated and cutaneous leishmaniasis on in vitro cytokine production.

BACKGROUND: Disseminated leishmaniasis is an emerging infectious disease, mostly due to L. braziliensis, which has clinical and histopathological features distinct from cutaneous leishmaniasis. METHODS: In the current study we evaluated the in vitro production of the cytokines IFN-gamma, TNF-alpha, IL-5 and IL-10 by peripheral blood mononuclear cells (PBMC) from 15 disseminated leishmaniasis and 24 cutaneous leishmaniasis patients upon stimulation with L. braziliensis antigens genotyped as disseminated leishmaniasis or cutaneous leishmaniasis isolates. RESULTS: Regardless of the source of L. braziliensis antigens, PBMC from cutaneous leishmaniasis patients produced significantly higher IFN-gamma than PBMC from disseminated leishmaniasis patients. Levels of TNF-alpha by PBMC from cutaneous leishmaniasis patients were significantly higher than disseminated leishmaniasis patients only when stimulated by genotyped cutaneous leishmaniasis antigens. The levels of IL-5 and IL-10 production by PBMC were very low and similar in PBMCs from both disseminated leishmaniasis and cutaneous leishmaniasis patients. The immune response of each patient evaluated by the two L. braziliensis antigens was assessed in a paired analysis in which we showed that L. braziliensis genotyped as disseminated leishmaniasis isolate was more potent than L. braziliensis genotyped as cutaneous leishmaniasis isolate in triggering IFN-gamma and TNF-alpha production in both diseases and IL-5 only in cutaneous leishmaniasis patients. CONCLUSION: This study provides evidence that antigens prepared from genotypically distinct strains of L. braziliensis induce different degrees of immune response. It also indicates that both parasite and host play a role in the outcome of L. braziliensis infection.