RESUMO
The Hypoxyloideae (Xylariaceae with Nodulisporium-like anamorphs) were evaluated by a morphological and HPLC-based chemotaxonomic survey of more than 2000 specimens and cultures. Conspecificity of recent records with ancient type specimens were established in many cases by HPLC, since their characteristic metabolites may remain stable for over 200 years. Most constitute novel natural products that were identified in the course of concurrent "mycochemical" studies. A comparison of HPLC profiles considering relationships within the Hypoxyloideae as inferred from the biogenesis of these pigments agreed fairly with concurrent molecular phylogenetic studies, based on sequences of actin, beta-tubulin, and 5.8S/ITS nrDNA genes. Anamorphic morphology and secondary metabolism of cultures agreed well at generic level and above. A combination of chemical and morphological traits is favored over PCR-based approaches for species discrimination, if only relatively few taxa of these diverse genera have been sequenced. An overview on the chemical structures and biological activities of the characteristic metabolites is provided, their ecological importance is discussed, and the utility of chemotaxonomy to support and predict phylogenetic relationships in the Hypoxyloidae is demonstrated. A polythetic approach is most useful to elucidate the phylogeny of the Xylariaceae. Chemotaxonomy to assess fungal biodiversity has considerable utility(AU)
Assuntos
Pigmentos Biológicos/química , Pigmentos Biológicos/isolamento & purificação , Resorcinóis/química , Resorcinóis/isolamento & purificação , Tubulinos/genética , Xylariales/química , Xylariales/classificação , Xylariales/genética , Reação em Cadeia da Polimerase , Ácido Benzoico/química , Ácido Benzoico/isolamento & purificação , Benzopiranos/química , Benzopiranos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Naftalenos/química , Naftalenos/isolamento & purificação , FilogeniaRESUMO
En los últimos años el arsenal de fármacos orales útiles en el tratamiento de la diabetes mellitus tipo 2 se ha ampliado. La repaglinida es el primero de una nueva clase de antidiabéticos orales derivados del ácido benzoico, no pertenecientes al grupo de las sulfonilureas, con acción estimuladora de la secreción de insulina. La repaglinida mejora la regulación de la glucemia prandial, al corregir la secreción disminuida y retrasada de insulina relacionada con las comidas en los diabéticos tipo 2. Utilizada en monoterapia tiene una eficacia similar a las sulfonilureas o a la metformina en reducir la glucemia basal y la hemoglobina glucosilada. (AU)
