Recebido em 31/8/04; aceito em 11/3/05; publicado na web em 10/8/05 ANTIFUNGAL COMPOUNDS OF Xylaria sp., AN ENDOPHYTIC FUNGUS ISOLATED FROM Palicourea marcgravii (RUBIACEAE). Five compounds, 2-hexyl-3-methyl-butanodioic acid (1), cytochalasin D (2), 7-dechlorogriseofulvin (3), cytochalasin B (4) and griseofulvin (5), have been isolated from the endophytic fungus Xylaria sp., and their structures were elucidated on the basis of spectroscopic data. In the bioautography assay against Cladosporium cladosporioides and Cladosporium sphaerospermum, compounds 1 and 2 were found to be active while compounds 3, 4 and 5 did not show antifungal activity.
Recebido em 14/12/05; aceito em 4/8/06; publicado na web em 10/1/07 ALKALOIDS FROM FLOWERS AND LEAVES OF Erythrina speciosa ANDREWS. In vitro bioassays with leave extracts of Erythrina speciosa showed promising activity against Trypanosoma cruzi. From the flowers of E. speciosa two alkaloids were isolated: erysotrine and erythartine. The leaves furnished one alkaloid, nororientaline. The structures were determined on the basis of spectroscopic evidence. This is the first report about the investigation of alkaloids in flowers and leaves of this species, as well the first report of nororientaline occurrence in this plant.Keywords: Erythrina speciosa; alkaloids; trypanocidal activity. INTRODUÇÃOOs extratos de folhas, cascas e de raízes de várias espécies do gênero Erythrina são usados na medicina popular no tratamento de diversas doenças, tais como disenteria, asma, dor estomacal, infertilidade feminina e, principalmente, infecções microbianas. O gênero é conhecido pela bioprodução significativa de alcalóides, sendo que estudos mais recentes revelaram também a presença de flavanonas, isoflavonas e pteropcarpanos , o que serviu como estímulo adicional para iniciar atividades de investigação química da espécie.O presente trabalho descreve o isolamento e a caracterização estrutural dos alcalóides erisotrina (1) e eritrartina (2) obtidos do extrato etanólico das flores e da nororientalina (3), do extrato etanólico das folhas de E. speciosa. A literatura registra o isolamento de alcalóides de sementes e cascas de E. speciosa 2,10,11 , porém este é o primeiro registro de estudo de flores e folhas desta espécie. RESULTADOS E DISCUSSÃOO fracionamento cromatográfico do extrato etanólico das flores de E. speciosa forneceu um grupo de frações eluídas com uma mistura de diclorometano/etanol 10%, que revelou teste positivo com reagente de Dragendorff, sugerindo a presença de substância nitrogenada. A purificação deste material resultou no isolamento e posterior identificação dos alcalóides erisotrina (1) e eritrartina (2) .
One new natural product, 1-phenylethyl-O-α-L-rhamnopyranoside, together with eight known diketopiperazines and two benzene derivatives were isolated from the endophytic fungus Colletotrichum crassipes, whereas six known compounds including two griseofulvins, three cytochalasins and one dihydroisocoumarin were produced from the endophyte Xylaria sp., both endophytic fungi are associated with leaves of Casearia sylvestris. Cyclo(D)-Pro-(D)-Phe, N-(2-phenylethyl)acetamide and 5-carboxy-6-hydroxy-3-methyl-3,4-dihydroisocoumarin exhibited potent antifungal activity against Cladosporium cladosporioides and C. sphaerospermum. The compounds cyclo(D)-Pro-(D)-Phe, griseofulvin, cytochalasin B and cytochalasin D exhibited antioxidant activity, and the compounds cyclo(D)-Pro-(D)-Phe, cytochalasin B and cytochalasin C showed potent acetylcholinesterase (AChE) inhibition. In addition, this is the first report on the isolation of secondary metabolites from two endophytic fungal strains, associated with Casearia sylvestris.
a b s t r a c tA set of five fungal species, Botrytis cinerea, Trichoderma viride and Eutypa lata, and the endophytic fungi Colletotrichum crassipes and Xylaria sp., was used in screening for microbial biocatalysts to detect monooxygenase and alcohol dehydrogenase activities (for the stereoselective reduction of carbonyl compounds). 4-Ethylcyclohexanone and acetophenone were biotransformed by the fungal set. The main reaction pathways involved reduction and hydroxylations at several positions including tertiary carbons. B. cinerea was very effective in the bioreduction of both substrates leading to the chiral alcohol (S)-1-phenylethanol in up to 90% enantiomeric excess, and the cis-trans ratio for 4-ethylcyclohexanol was 0:100. trans-4-Ethyl-1-(1S-hydroxyethyl)cyclohexanol, obtained from biotransformation by means of an acyloin-type reaction, is reported here for the first time. The absolute configurations of the compounds trans-4-ethyl-1-(1S-hydroxyethyl)cyclohexanol and 4-(1S-and 4-(1R-hydroxyethyl)cyclohexanone were determined by NMR analysis of the corresponding Mosher's esters.
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