Rikke Nørbæk

Flower pigment composition of Crocus species and cultivars used for a chemotaxonomic investigation

Abstract A survey of floral anthocyanins and other flavonoids by analytical high-performance liquid chromatography (HPLC) was performed among 70 species and subspecies, 43 cultivars and six artificial hybrids of Crocus and the results were compared with taxonomical delimitations established by Mathew (The Crocus. B.T. Batsford Ltd, London, 1982). Nine anthocyanins were detected. The Crocus species and cultivars were placed into seven chemotypes according to their contents of 3,7- di - O -, 3,5- di - O -glucosides or 3- O -rutinosides of delphinidin and petunidin and to the presence of 3,7- di - O -malonyl-glucosides of petunidin and malvidin and delphinidin 3- O -glucoside-5- O -malonylglucoside. These malonated anthocyanins have only been found in Crocus and may be characteristic for this genus. The same 18 flavonoids were detected in every taxon. However, quantitative differences were noted and four chemotypes of Crocus were defined by their major contents of flavonoids. Six of the flavonoids appear to be unique for Crocus. The anthocyanin/flavonoid patterns of some of the taxa provide a valuable supplement to the taxonomy based on morphological and cytological patterns. Most chemotypes were represented in several series but the chemical data were useful in distinguishing different species. For all series except Series h the chemical data were very similar for all subspecies or accessions within a species, and chemotypes within a series were more similar than between series. However for six species, the analyses suggest that they should be further investigated using other methods, to evaluate their relations to other series.

Flavonol glycosides from flowers of Crocus speciosus and C. antalyensis

From the flower extracts of Crocus speciosus and C. antalyensis nine flavonol glycosides have been isolated. One of these products is a new flavonol glycoside identified as kaempferol 3-O-alpha-(2,3-di-O-beta-D-glucopyranosyl)rhamnopyranoside by UV, mass and NMR spectroscopy.

Anthocyanins from flowers of Cichorium intybus

From the blue perianth segments of Cichorium intybus we isolated four anthocyanins. The pigments were identified as delphinidin 3,5-di-O-(6-O-malonyl-beta-D-glucoside) and delphinidin 3-O-(6-O-malonyl-beta-D-glucoside)-5-O-beta-D-glucoside and the known compounds were delphinidin 3-O-beta-D-glucoside-5-O-(6-O-malonyl-beta-D-glucoside) and delphinidin 3,5-di-O-beta-D-glucoside. In addition 3-O-p-coumaroyl quinic acid has been identified.

Anthocyanins from flowers of Lilium (Liliaceae)

Abstract The perianth segments of 10 cultivars including Asiatic and Oriental hybrids and one species of Lilium, were investigated by HPLC for their content of anthocyanins. The investigation revealed the presence of one new and one known anthocyanin. The novel anthocyanin, cyanidin 3-O-β-rutinoside-7-O-β-glucoside and cyanidin 3-O-β-rutinoside were both isolated from the red flowers of Lilium Holean. Within both Asiatic and Oriental hybrids, cultivars with or without the novel anthocyanin were found, whereas the known anthocyanin was always present in none-white genotypes. The structural determination of the compounds was achieved by 1D and 2D NMR techniques and other spectral evidence.

Flavonoids from flowers of two Crocus chrysanthus-biflorus cultivars: “Eye-catcher” and “Spring Pearl” (Iridaceae)

Abstract Eight flavonoids, of which five are new flavonols, were isolated from perianth segments of two Crocus chrysanthus-biflorus cultivars. The new flavonols were identified as 3- O -α- l -(2- O -β- d -glucopyranosyl)rhamnopyranoside-7- O -β- d -glucopyranosides of kaempferol, quercetin and myricetin, and two were the corresponding modified kaempferol triglycosides acylated at OH-6 of the 7-glucoside with malonic acid or acetic acid. The flavonols coexist with the known 7- O -β- d -glucosides of dihydrokaempferol and apigenin and with isorhamnetin 3,4′-di- O -β- d -glucoside. Complete structural determination of all compounds was achieved using 1-D and 2-D NMR techniques and other spectral evidence.

Anthocyanins from flowers of Crocus (iridaceae)

Abstract The perianth segments of three cultivars of Crocus were investigated by HPLC for their content of anthocyanins. The investigation revealed the presence of four known and two new anthocyanins. The novel anthocyanins were isolated from the blue flowers of C. chrysanthus ‘Skyline’, and identified as petunidin 3-O-(6-O- malonyl -β- d -glucoside )-7-O-(6-O- malonyl -β- d -glucoside ) and malvidin 3-O-(6-O- malonyl -β- d -glucoside )-7-O-(6-O- malonyl -β- d -glucoside ) . The anthocyanins, isolated from the blue flowers of C. sieberi ssp. sublimis ‘Tricolor’, were identified as 3,5-β- d -diglucosides of delphinidin and petunidin, and from C. chrysanthus ‘Eyecatcher’ were as their 3-β-rutinosides. The complete structural determination of each compound was achieved by use of 1D and 2D NMR techniques and other spectral evidence.

Anthocyanins in chilean species of Alstroemeria

Abstract The tepals of 28 Chilean Alstroemeria species were investigated by HPLC for their content of anthocyanins. The investigation revealed the presence of at least seven anthocyanins of which six were identified. The anthocyanins were isolated from the cultivars ‘Regina’ and ‘Cana’ and identified as 6-hydroxydelphinidin 3-rutinoside, 6-hydroxycyanidin 3-rutinoside, delphinidin 3-rutinoside, cyanidin 3-rutinoside, delphinidin 3-malonylglucoside and cyanidin 3-malonylglucoside. The position of the malonyl group in the acylated anthocyanins could not be determined due to their instability and low amounts. Most of the Alstroemeria species investigated can be placed into three groups regarding their contents of major pigments. The use of anthocyanins as taxonomic markers in Alstroemeria is discussed.

Further anthocyanins from flowers of Crocus antalyensis (Iridaceae)

As a part of a continuing chemotaxonomic survey of pigments in Crocus two new and three known anthocyanins have been isolated from the blue perianth segments of Crocus antalyensis [Mathew, B., The Crocus. B.T. Batsford, London]. The novel anthocyanins were identified as delphinidin 3-O-(β-d-glucopyranoside)-5-O-(6-O-malonyl-β-d-glucopyranoside and petudin 3,7-di-O-(β-d-glucopyranoside. Further 3,7-di-O-β-d-glucoside of delphinidin was isolated together with two minor components, 3,5-di-O-β-d-glucosides of delphinidin and petunidin. The complete structural determination of the compounds was achieved by use of 1D and 2D NMR techniques and other spectral evidence.

Changes in Concentrations of Cytokinins (CKs) in Root and Axillary Bud Tissue of Miniature Rose Suggest that Local CK Biosynthesis and Zeatin-Type CKs Play Important Roles in Axillary Bud Growth

Involvement of cytokinins (CKs) in axillary bud growth of miniature rose was studied. Variation in root formation and axillary bud growth was induced by two indole 3-butyric acid (IBA) pretreatments in two cutting sizes. At six physiological developmental stages around the onset of axillary bud growth, concentrations of CKs were determined in both root and axillary bud tissue by liquid chromatography combined with electrospray tandem mass spectrometry (LC-ESP-MS/MS). Chronological early onset of axillary bud growth occurred in long cuttings pretreated at low IBA concentration, whereas physiological early root formation was associated with long cuttings and high IBA concentration. The CKs zeatin (Z), isopentenyl adenine (iP), zeatin riboside (ZR), dihydrozeatin riboside (DHZR), isopentenyl adenosine (iPA), zeatin O-glucoside (ZOG), zeatin riboside O-glucoside (ZROG), zeatin riboside 5′-monophosphate (ZRMP), and isopentenyl adenosine 5′-monophosphate (iPAMP) were detected. Concentrations of CKs in axillary bud tissue far exceeded those in root tissue. Indole 3-butyric acid pretreatment influenced the concentration of CKs in axillary bud tissue more than did cutting size, whereas pretreatments only slightly affected CKs in root tissue. The dominant CKs found were iPAMP and ZR. An early and large increase in iPAMP indicated rapid CK biosynthesis in rootless cuttings, suggesting that green parts, including the axillary bud, can synthesize CKs. At the onset of axillary bud growth an increase in concentration of Z, ZR, ZRMP, ZOG, and ZROG was largely coincident with a decrease in iPAMP, iPA, iP, and DHZR. After the onset of axillary bud growth, CK content largely decreased. These results strongly indicate a positive role for CKs in axillary bud growth, and presumably ZRMP, ZR, and Z are active in miniature rose.