Recebido em 25/9/06; aceito em 23/5/07; publicado na web em 9/11/07 DIVERSITY OF POLYKETIDES PRODUCED BY Penicillium SPECIES ISOLATED FROM Melia azedarach AND Murraya paniculata. Eight compounds comprising four groups of polyketides, the xanthone fusarindin, the mixed peptide alkaloid-polyketide GKK1032, the anthraquinones crisophanol, citreoveridin and janthinone, and the azaphylones dihydrocitrinone, citrinin and citrinin H-1, were identified in Penicillium species isolated as endophytic fungi from Melia azedarach and Murraya paniculata. The antibacterial activity of the azaphylones was tested and showed that citrinin H-1 is more active than citrinin.Keywords: polyketide, endophytic fungus; Penicillium. INTRODUÇÃOOs policetídeos de origem fúngica constituem uma grande classe de metabólitos secundários, apresentando uma das maiores diversidades estruturais entre os produtos naturais 1 . A maioria desses compostos é ativa em diversos sistemas biológicos 2 . Portanto, a busca de policetídeos em microorganismos vem sendo apontada como uma boa estratégia para pesquisas de substâncias bioativas.Os policetídeos são biossintetisados por um conjunto de enzimas usualmente denominadas de "policetídeo sintases" (ou PKS, "Polyketide Synthase"). Segundo Hertweck 2 , as enzimas, cetosintase (KS), aciltransferase (AT), proteína carregadora de grupo ácido (ACP), cetoredutase (KR) e deidratase (DH) devem fazer parte do conjunto PKS. A ação dessas enzimas em conjunto ou uma expressão diferenciada de alguma delas deve resultar em diferentes classes de policetídeos. Dada a grande importância dos policetídeos, esforços vêm sendo feitos para se conseguir a expressão controlada dos genes que codificam as enzimas PKS 2 . Na natureza, a expressão dos genes PKS é dependente de uma série de fatores ainda pouco conhecidos. Conforme a atuação do conjunto das enzimas PKS durante a biossíntese, os policetídeos podem ser compostos aromáticos poliidroxilados (como a maioria dos pigmentos fúngicos), compostos alifáticos pouco oxigenados (ou policetídeos parcialmente reduzidos, como a lovastatina) e alifáticos altamente reduzidos (e.g. ácidos graxos) 3,4 . O entendimento de como esses fatores de expressão gênica atuam é um grande desafio. A busca por policetídeos em cepas fúngicas selvagens pode auxiliar nesses estudos, além de apontar novas fontes para compostos de reconhecida importância pelas atividades biológicas.Em trabalhos anteriores relacionados ao estudo do metabolismo secundário de microorganismos endofíticos isolados de Melia azedarach, foram isolados vários policetídeos bioativos do fungo Penicillium janthinellum 5. Um desses compostos, a citrinina, mostrou importante atividade inibitória de crescimento de Leishmania mexicana, e outros compostos mostraram significativos efeitos inibidores do crescimento de bactérias. Na busca por uma maior diversidade estrutural desses compostos em fungos, está sendo relatada agora a identificação dos policetídeos emodina (1), citreoroseina (2), janthinona (3), diidrocitrinona (4) e citrinina H-1 (6)...

Antibiotic resistance results in higher medical costs, prolonged hospital stays and increased mortality and is rising to dangerously high levels in all parts of the world. Therefore, this study aims to search for new antimicrobial agents through bioprospecting of extracts of endophytic fungi from Bauhinia guianensis, a typical Amazonian plant used in combating infections. Seventeen (17) fungi were isolated and as result the methanolic extract of the fungus Exserohilum rostratum showed good activity against the bacteria tested. The polyketide monocerin was isolated by the chromatographic technique, identified by NMR and MS, showing broad antimicrobial spectrum.

This study evaluated in vitro activity of ethanol extract, fractions, and isolated substance from Amazon species against promastigotes of L. amazonensis. The ethanol extracts were concentrated and fractionation. The anti-promastigote activity was evaluated through the cell viability assessment method (MTT). The ethanol extract, fractions, and isolated substance from Himatanthus articulatus and Parahancornia fasciculata were inactive in promastigote of L. amazonensis, as the ethanol extract of Physalis angulata. The hexane fractions from different parts of Montrichardia linifera showed anti-promastigote activity probably due to the presence of steroids and terpenes. All species in studies were inactive, except of M. linifera. The few polar constituents can be responsible for the activity. Therefore, the isolation and purification of the active on L. amazonensis promastigotes are urgently required.

The present work reports the isolation of eight compounds from Pestalotiopsis sp. EJC07 isolated as endophytic from Bauhinia guianensis, a tipical plant of the Amazon. The compounds (4S)-4,8-dihydroxy-1-tetralone (1), uracil (2), uridin (3), p-hydroxybenzoic acid (4), ergosterol (5), ergosterol peroxide (6), cerevisterol (7) and ducitol (8) were isolated by chromatographic procedures and identifi ed by spectral methods of 1D and 2D NMR and MS. The compound 1 is being reported for the fi rst time in the genus Pestalotiopsis.

The use bulbs of Eleutherine bulbosa for treatament of diseases caused by malaria, amoeba and bacteria. This study accomplished the botanical and phytochemical characterization, antimicrobial activity and cytotoxic of E. bulbosa. For the anatomical studies, the studied material was fixed in formaldehyde – acetic acid and ethanol and it was dyed in safranin and in astra blue. For histochemistry, was fixed in buffered neutral formalin and in ferrous sulphate in formalina. Ethanolic Extract (EE) was submitted to fractionation in a chromatographic column and four (4) fractions were obtained from it. The Dichloromethane Fraction (DF) was submitted to a new fractionation. The biological activity was evalueted by diffusion in agar, microdilution and celular viability MTT. The bulb of E. bulbosa is characterized by a reduced caulinar axis and by succulent amiliferous cataphylls, epidermis with the presence of anthocyanins, homogeneous mesophyll with idioblasts of prismatic crystals of calcium oxalate and phenolic compounds. In agar diffusion it was observed that EE, DF and ethyl acetate fraction (ACF) were active for Staphylococcus aureus. In microdilution, DF (Inhibitory minimum concentration= 125 µg/ mL) was more active. For all samples the Minimous Bactericidal Concentration was >1000 µg/ mL. The fractionation contributes positively with the citotoxicity, being subfractions S1 and S2 the most citotoxic ones. The Fraction Dichloromethane was the most active one for S. aureus and more citotoxicity to VERO cells. Probably the less citotoxicity of EE is related to the presence of anthocyanins that are present on bulbs epidermis.