YYÜ GCRIS Basic veritabanının içerik oluşturulması ve kurulumu Research Ecosystems (https://www.researchecosystems.com) tarafından devam etmektedir. Bu süreçte gördüğünüz verilerde eksikler olabilir.

Browsing by Author "Jensen, SR"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Article
    Acylated Flavone Glycosides From Veronica
    (Pergamon-elsevier Science Ltd, 2003) Albach, DC; Grayer, RJ; Jensen, SR; Özgökce, F; Veitch, NC
    A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two unusual allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-rhamnopyranosyl(1"'-->2")[6"-O-acetyl-beta-glucopyranoside] and 6-hydroxyluteolin 7-O-(6"-O -(E)-caffeoyl)-beta-glucopyranoside, respectively. Isoscutellarein 7-O-(6"'-O-acetyl)-beta-allopyranosyl(1'''--> 2")-beta-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete H-1 and C-13 NMR spectral assignments are presented for both isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens. (C) 2003 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Article
    Veronica
    (Pergamon-elsevier Science Ltd, 2005) Albach, DC; Jensen, SR; Özgökce, F; Grayer, RJ
    Molecular phylogenetic analyses have revealed many relationships in Veronica (Plantaginaceae) never anticipated before. However, phytochemical characters show good congruence with DNA-based analyses. We have analysed a combined data set of 49 species and subspecies derived from the nuclear ribosomal ITS-region (18 new sequences) and the plastid trnL-F region (12 new sequences) of Veronica emphasizing subgenera Chamaedrys and Pocilla and separate analyses of subgenera Pentasepalae (ITS only) and Pseudolysimachium. Results for subgenus Chamaedrys show that European and Asian perennial species are monophyletic sister groups with the annual species consecutive sisters to them. All species of Veronica that contain cornoside are found in this subgenus, although some species seem to have secondarily lost the ability to produce this compound. Subgenera Pocilla and Pentasepalae are well supported sister groups characterized by the occurrence of 8-hydroxyflavones. The traditional subsection Biloba of subgenus Pocilla is biphyletic with Veronica intercedens being clearly separate from the rest of the group. This result is mirrored by the unusual phytochemical arsenal of V. intercedens, which is the only species in the genus analysed to date to contain melittoside and globularifolin. Subgenus Pentasepalae appears to be a clade of diverse lineages from southwestern Asia and a single European clade. Species shown to have 6-hydroxyflavones do not form a monophyletic group. Subgenus Pseudolysimachium seems to have originated in Eastern Asia. 6-Hydroxyflavones acylated with phenolic acids are common in this subgenus but may have originated only later in the evolution of the group. Possible chemotaxonomic markers for other groups are discussed. (c) 2005 Elsevier Ltd. All rights reserved.