ISHS Acta Horticulturae 673: IX International Symposium on Flower Bulbs
FLAVONOIDS AND THEIR DISTRIBUTION PATTERNS IN THE FLOWERS OF GLADIOLUS CULTIVARS |
| Authors: | T. Takemura, Y. Takatsu, M. Kasumi, W. Marubashi, T. Iwashina |
| Keywords: | Iridaceae, flower color, flavonols, anthocyanins, malvidin, kaempferol |
| Abstract:
The Gladiolus is the largest genus in the family Iridaceae that contains many bulbous plants from southern Africa. Flower coloration varies from white, yellow, pink, red to purple. Some anthocyanins have been isolated as flower pigments, but other flavonoids are hardly reported. In this survey, the anthocyanins and other flavonoids of the bluish cultivar, G. x grandiflora ‘Ariake’ were isolated and identified. When absorption spectra of the fresh perianth of ‘Ariake’ was compared with that of isolated anthocyanin, the former absorption maxima bathochromically shifted than the latter one, so it was presumed that the flower color was changed to more purple by the presence of copigments. It was shown by HPLC analysis that three anthocyanins and some flavonoids are present in the crude extract. The major anthocyanin was identified as malvidin 3,5-di-O-glucoside (malvin) and the two minor ones were characterized as malvidin glycosides. Of the flavonoids, three were identified as kaempferol 3-O-rutinoside, kaempferol 3-O-sophoroside and quercetin 3-O-rutinoside by LC-MS, UV, 1H- and 13C-NMR spectra, and direct PC and HPLC comparisons with authentic specimens. The remaining pigments were characterized as flavonol 3-O-glycosides based on kaempferol, quercetin, myricetin, laricitrin and syringetin. The pigment patterns of representative red, purple, pink, white and yellow cultivars were surveyed by HPLC. The purple flower cultivar contained many flavonols compared with other flower colors, e.g. pink and red suggesting that the flavonol glycosides represent the more purplish color as copigments. | |
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