Navegando por Palavras-chave "Benzophenones"

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    Leishmanicidal activity of benzophenones and extracts from Garcinia brasiliensis Mart. fruits
    (Elsevier B.V., 2010-04-01) Pereira, I. O.; Marques, M. J.; Pavan, A. L. R.; Codonho, B. S.; Barbieri, C. L. [UNIFESP]; Beijo, L. A.; Doriguetto, A. C.; D'Martin, E. C.; Santos, M. H. dos; Universidade Federal de São Paulo (UNIFESP)
    Infections by protozoans of the genus Leishmania are the major worldwide health problem, with high endemicity in developing countries. the drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which exert renal and cardiac toxicity. Thus, there is a strong need for safer and more effective treatments against leishmaniasis. the present study was designated to evaluate, by a bioguided assay, the leishmanicidal activity of extracts (hexane, ethyl-acetate and ethanolic) and molecules both obtained by means of extraction from pericarps of Garcinia brasiliensis fruits. the hexane extract presented the best activity on the extracellular (promastigotes) and intracellular (amastigotes) forms of Leishmania (L.) amazonensis, when compared to the other extracts. Based on these findings, this extract was fractionated by silica gel column chromatography, affording nine fractions then resulting in three purified prenylated benzophenones - 7-epi-clusianone (1), garciniaphenone (2) and guttiferone-a (3). They showed significant activity on Leishmania (L) amazonensis, and little toxicity for mammalian cells. Structure-activity relationships were evaluated showing that the IC(50) value displayed is dependent of prenyl groups and phenolic hydroxyls number, and inversely proportional to the hydrophobicity. Our results are promising, showing that these compounds are biologically active on Leishmania (L) amazonensis. (C) 2009 Elsevier GmbH. All rights reserved.
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    Natural polyprenylated benzophenones inhibiting cysteine and serine proteases
    (Elsevier B.V., 2009-03-01) Martins, Felipe T.; Assis, Diego M.; Santos, Marcelo H. dos; Camps, I.; Veloso, Marcia P.; Juliano, Maria A. [UNIFESP]; Alves, Lira C.; Doriguetto, Antonio C.; Univ Fed Alfenas; Universidade Federal de São Paulo (UNIFESP)
    We have investigated the in vitro inhibition of papain, trypsin, and cathepsins B and G by five benzophenone-type compounds, three natural ones isolated from Garcinia brasiliensis and two synthetic derivatives. the activities of pentaprenylated trihydroxy-substituted benzophenone guttiferone A (1) on all assayed enzymes were approximately 2-69 folds higher than that manifested by mono-hydroxylated tetraprenylated and triprenylated compounds epiclusianone (2) and garciniaphenone (3), respectively, the other natural benzophenones that also inhibited significantly the four enzymes. Differently, the synthetic derivatives 2,2',4-trihydroxybenzophenone (4) and diphenylmethanone (5) have inhibited weakly the studied proteases. Furthermore, compound 1 has bonded preferentially to cathepsin G, once its IC(50) value (2.7 +/- 0.1 mu M) on such peptidase is quite similar to that of the classical inhibitor of serine proteases, chymostatin (2.1 +/- 0.1 mu M). Interesting structure-activity relationships (SARs) were confirmed by flexible docking simulations, likewise the potential usefulness of natural compound 1 as antitumoral drug is strengthened by our results concerning the antiproteolytic activity. (C) 2008 Elsevier Masson SAS. All rights reserved.