Xanthone
Mostrando 13-24 de 27 artigos, teses e dissertações.
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13. Chemical constituents of Salacia elliptica (Celastraceae)
The chemical investigation of Salacia elliptica allowed to the isolation of 20 constituents: two polyols, one xanthone, a mixture of long chain hydrocarbons, one carboxylic acid, one polymer, two steroidal compounds, one aromatic ester and eleven pentacyclic triterpenes. These triterpenes include 3β-stearyloxy-oleanane, 3β-stearyloxy-ursane, one seco-fried
Química Nova. Publicado em: 2010
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14. Isolamento e avaliação biológica de compostos fenólicos de espécies de hypericum nativas do sul do Brasil
The pharmacological effects of some Hypericum species are worldwide recognized, mostly by the comproved efficacy of H. perforatum as antidepressant. The south Brazilian species have been showing promissing results. Hypericum polyanthemum and H. caprifoliatum presented antinociceptive effect, while an antidepressant-like activity of H. caprifoliatum was repor
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2010
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15. Constituintes químicos de Parmotrema lichexanthonicum Eliasaro & Adler: isolamento, modificações estruturais e avaliação das atividades antibiótica e citotóxica
From the lichen Parmotrema lichexantonicum were isolated the depsidone salazinic acid, the xanthone lichexanthone, and the depside atranorin. The two major compounds, salazinic acid and lichexanthone, were selected for structure modifications. Salazinic acid afforded O-alkyl salazinic acids, some of them potentially cytotoxic against tumor cell lines (HCT-8,
Química Nova. Publicado em: 2009
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16. Diversidade de policetídeos produzidos por espécies de Penicillium isoladas de Melia azedarach e 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 panic
Química Nova. Publicado em: 2007
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17. Chemical and antimicrobial activity of stem Kielmeyera cuspidata. / Estudo químico e da atividade antimicrobiana do caule da Kielmeyera cuspidata.
The present work describes the phytochemical investigation Kielmeyera cuspidata that belongs to the family Clusiaceae. This species was studied chemically for the first time. Many species of Clusiaceae family are known to possess mainly xanthones that exhibit some important bioactivities. The hexane and methanolic extract were obtained by percolation of the
Publicado em: 2006
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18. Antibacterial xanthones from Kielmeyera variabilis mart. (Clusiaceae)
The bioassay-guided fractionation of stems from Kielmeyera variabilis, traditionally used in Brazilian folk medicine, yielded assiguxanthone-B (1), kielcorin (4), 2,5-dihydroxybenzoic acid (3), and a mixture of xanthones containing assiguxanthone-B (1) and 1,3,5,6-tetrahydroxy-2-prenylxanthone (2) (1:1 w/w). The xanthone mixture inhibited Staphylococcus aure
Memórias do Instituto Oswaldo Cruz. Publicado em: 2003-06
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19. Aspectos quimicos da polinização de especies do genero Clusia e sintese da (+)-cis-nortailoriona e 7S-isotiociano-7, 8-Di-hidro-alfa-bisaboleno
This work has been divided in two main topics: a) Natural product isolation. In the first topic we have developed a non traditional phytochemical research concerning the identification of the constituents of floral oils and resins and their role in the Clusia polination phenomenon as well as their importance in the pollinating bee s life.We have focused on t
Publicado em: 1997
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20. Initial reactions of xanthone biodegradation by an Arthrobacter sp.
This study examined the catabolism of xanthone by an Arthrobacter sp. (strain GFB100) capable of growth on xanthone as its main source of carbon and energy. An early catabolic intermediate was 3,4-dihydroxyxanthone. This compound was isolated from the growth medium of a mutant strain of the Arthrobacter sp. which lacked the xanthone-inducible dihydroxyxantho
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21. Anthraquinones in the biosynthesis of sterigmatocystin by Aspergillus versicolor.
14C-labeled averufin, versiconal hemiacetal acetate, and versicolorin A were efficiently converted to sterigmatocystin by Aspergillus versicolor, thus providing experimental evidence that these anthraquinones are biosynthetic precursors of sterigmatocystin, a xanthone.
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22. Potentiation of an antimalarial oxidant drug.
In a previous report we described the synergistic antimalarial interaction between two structurally similar compounds, rufigallol and exifone. To explain this phenomenon, we proposed that exifone is transformed inside the parasitized erythrocyte into a xanthone with potent antimalarial properties. We speculated that the transformation process was induced by
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23. 3,4-Dihydroxyxanthone dioxygenase from Arthrobacter sp. strain GFB100.
Bacterial extradiol ring-fission dioxygenases play a critical role in the transformation of multiring aromatic compounds to more readily biodegradable aromatic or aliphatic intermediates. Arthrobacter sp. strain GFB100 utilizes an extradiol meta-fission dioxygenase, 3,4-dihydroxyxanthone dioxygenase (DHXD), in the catabolism of the three-ring oxygen heterocy
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24. Unified synthesis of caged Garcinia natural products based on a site-selective Claisen/Diels–Alder/Claisen rearrangement
A unified synthetic strategy toward caged Garcinia natural products has been designed and implemented. Central to the strategy is a tandem Claisen/Diels–Alder/Claisen rearrangement of a suitably substituted xanthone precursor to form forbesione (1a). Serving as a template, forbesione is then used to deliver representative members of this family, including
National Academy of Sciences.