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Flavonoid biosynthesis in petals of Rhododendron simsii

(1993) PHYTOCHEMISTRY. 33(6). p.1419-1426
Author
Organization
Abstract
The results of a comparative in vivo study of flavonoid biosynthesis in Rhododendron simsii petals, with [2-C-14]p-coumaric acid and [2-C-14]caffeic acid indicate that p-coumaric acid is the true precursor. Moreover, supplementary in vitro experiments with enzyme preparations show that p-coumaroyl-CoA is a much better substrate for chalcone synthase than caffeoyl-CoA. This suggests that in Rhododendron the 3'-hydroxylation of the B-ring occurs at the stage of a C-15 intermediate. In addition, flavonoid 3'-hydroxylase activity was demonstrated by means of comparative in vivo experiments with, respectively, [4a,6,8-C-14]naringenin and [4a,6,8-C-14]dihydrokaempferol as C-15 precursors. In both cases, the formation of radioactive 3',4'-hydroxylated co-pigments and anthocyanins was established. Furthermore, co-pigment biosynthesis may proceed via the sequence: naringenin, eriodictyol, dihydroquercetin (3'-hydroxylation at the flavanone stage), whereas the formation of the anthocyanins may take place via naringenin, dihydrokaempferol and dihydroquercetin (3'-hydroxylation at the dihydroflavonol level).
Keywords
RHODODENDRON-SIMSII, ERICACEAE, PETALS, BIOSYNTHESIS, FLAVONOIDS, ANTHOCYANINS, CO-PIGMENTS, CHALCONE SYNTHASE, FLAVONONE 3-HYDROXYLASE, 3'-HYDROXYLATION, INCANA R BR, PETUNIA-HYBRIDA, CELL-CULTURES, SINNINGIA-CARDINALIS, CHALCONE SYNTHASE, FLOWER EXTRACTS, GENETIC-CONTROL, 3-HYDROXYLASE, FLAVANONE, CONVERSION

Citation

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Chicago
De Cooman, Luc, Evert SW Everaert, Pierre Faché, Karel Vande Casteele, and Christiaan Vansumere. 1993. “Flavonoid Biosynthesis in Petals of Rhododendron Simsii.” Phytochemistry 33 (6): 1419–1426.
APA
De Cooman, Luc, Everaert, E. S., Faché, P., Vande Casteele, K., & Vansumere, C. (1993). Flavonoid biosynthesis in petals of Rhododendron simsii. PHYTOCHEMISTRY, 33(6), 1419–1426.
Vancouver
1.
De Cooman L, Everaert ES, Faché P, Vande Casteele K, Vansumere C. Flavonoid biosynthesis in petals of Rhododendron simsii. PHYTOCHEMISTRY. 1993;33(6):1419–26.
MLA
De Cooman, Luc, Evert SW Everaert, Pierre Faché, et al. “Flavonoid Biosynthesis in Petals of Rhododendron Simsii.” PHYTOCHEMISTRY 33.6 (1993): 1419–1426. Print.
@article{202899,
  abstract     = {The results of a comparative in vivo study of flavonoid biosynthesis in Rhododendron simsii petals, with [2-C-14]p-coumaric acid and [2-C-14]caffeic acid indicate that p-coumaric acid is the true precursor. Moreover, supplementary in vitro experiments with enzyme preparations show that p-coumaroyl-CoA is a much better substrate for chalcone synthase than caffeoyl-CoA. This suggests that in Rhododendron the 3'-hydroxylation of the B-ring occurs at the stage of a C-15 intermediate. In addition, flavonoid 3'-hydroxylase activity was demonstrated by means of comparative in vivo experiments with, respectively, [4a,6,8-C-14]naringenin and [4a,6,8-C-14]dihydrokaempferol as C-15 precursors. In both cases, the formation of radioactive 3',4'-hydroxylated co-pigments and anthocyanins was established. Furthermore, co-pigment biosynthesis may proceed via the sequence: naringenin, eriodictyol, dihydroquercetin (3'-hydroxylation at the flavanone stage), whereas the formation of the anthocyanins may take place via naringenin, dihydrokaempferol and dihydroquercetin (3'-hydroxylation at the dihydroflavonol level).},
  author       = {De Cooman, Luc and Everaert, Evert SW and Fach{\'e}, Pierre and Vande Casteele, Karel and Vansumere, Christiaan},
  issn         = {0031-9422},
  journal      = {PHYTOCHEMISTRY},
  keyword      = {RHODODENDRON-SIMSII,ERICACEAE,PETALS,BIOSYNTHESIS,FLAVONOIDS,ANTHOCYANINS,CO-PIGMENTS,CHALCONE SYNTHASE,FLAVONONE 3-HYDROXYLASE,3'-HYDROXYLATION,INCANA R BR,PETUNIA-HYBRIDA,CELL-CULTURES,SINNINGIA-CARDINALIS,CHALCONE SYNTHASE,FLOWER EXTRACTS,GENETIC-CONTROL,3-HYDROXYLASE,FLAVANONE,CONVERSION},
  language     = {eng},
  number       = {6},
  pages        = {1419--1426},
  title        = {Flavonoid biosynthesis in petals of Rhododendron simsii},
  url          = {http://dx.doi.org/10.1016/0031-9422(93)85102-W},
  volume       = {33},
  year         = {1993},
}

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