ChemInform Abstract: ISOLATION AND STRUCTURE ELUCIDATION OF NEAPOLITANOSE (O‐β‐D‐GLUCOPYRANOSYL‐(1 → 2)‐O‐(β‐D‐GLUCOPYRANOSYL‐(1 → 6))‐D‐GLUCOSE), A NEW TRISACCHARIDE FROM THE STIGMAS OF GARDEN CROCUSSES (CROCUS NEAPOLITANUS VAR.)

Rychener, M.; Bigler, Peter; Pfander, Hanspeter

doi:10.1002/chin.198422320

Cited by 3 publications

(3 citation statements)

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“…In cell suspension cultures of C. sativus a crocetin with two trisaccharide molecules has been identified, two O -β- D -glucopyranosyl-(1→2)- O -[β- D -glucopyranosyl-(1→6)]- D -glucose groups are present at each end of the molecule ( Dufresne et al, 1997 ), but this crocin has never been reported in the plant. This type of crocin with six glucose molecules, was also identified in Crocus neapolitanus , and accordingly the trisaccharide structure designated as neapolitanose ( Rychener et al, 1983 ). Crocin-3 has six glucose molecules and its retention time and spectral data suggest that crocin-3 is a crocetin neapolitanosyl di-ester.…”

Section: Discussionmentioning

confidence: 91%

Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus

et al. 2015

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Crocin biosynthesis in Crocus has been proposed to proceed through a zeaxanthin cleavage pathway catalyzed by carotenoid cleavage dioxygenase 2 (CCD2), and followed by glucosylation reactions catalyzed by CsGT2 (UGT74AD1). In Crocus ancyrensis flowers, crocins with eight (crocin-1), seven (crocin-2), and six glucose (crocin-3) moieties accumulated both in stigma and tepals. We have characterized the structure of these highly glucosylated crocins and follow up their accumulation by high-resolution liquid chromatography coupled with diode array detector along the development of both tissues, and coupled to the isolation and analysis of the expression of eighteen genes (PSY-I, PSY-II, PDS-(I-V), ISO-ZDS, ZDS, CtrISO, LYC-I and II, BCH, CaCCD2, UGT74AD2-5) related with the apocarotenoid metabolism in C. ancyrensis tepals and stigmas. Structure elucidation of crocin-1 and crocin-2 was done by the combined use of 1D and 2D [1H, 1H] (gCOSY and TOCSY and ROESY) and [1H-13C] NMR experiments, revealing that for crocin-1 was all-trans-crocetin O-[β-D- Glucopyranosyl)-(1→4)-(β-D-glucopyranosyl)-(1→2)]-O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranosyl diester, while crocin-2 showed an identical structure except for the absence of one glucose residue in one end of the molecule. Crocins accumulation was not synchronically regulated in stigma and tepals, although in both cases crocins accumulation parallels tissue development, decreasing at anthesis. The expression of the carotenogenic genes PSY, ZDS-V, BCH, and LCY-II was correlated with crocins accumulation. In addition, CaCCD2 and only one of the four glucosyltransferase encoding genes, UGT74AD2, were highly expressed, and the expression was correlated with high levels of crocins accumulation in stigma and tepals.

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Section: Discussionmentioning

confidence: 91%

Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus

et al. 2015

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“…The crocins pattern of several autumn Crocus stigmas had been analysed previously [16], but only one study has been performed on one spring-flowering species [44]. The detection of crocins with different glucosylation profiles in the tepals of these species, prompted us to determine whether crocins follow a similar pattern in the stigma tissue.…”

Section: Resultsmentioning

confidence: 99%

Crocins with High Levels of Sugar Conjugation Contribute to the Yellow Colours of Early-Spring Flowering Crocus Tepals

et al. 2013

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Crocus sativus is the source of saffron spice, the processed stigma which accumulates glucosylated apocarotenoids known as crocins. Crocins are found in the stigmas of other Crocuses, determining the colourations observed from pale yellow to dark red. By contrast, tepals in Crocus species display a wider diversity of colours which range from purple, blue, yellow to white. In this study, we investigated whether the contribution of crocins to colour extends from stigmas to the tepals of yellow Crocus species. Tepals from seven species were analysed by UPLC-PDA and ESI-Q-TOF-MS/MS revealing for the first time the presence of highly glucosylated crocins in this tissue. β-carotene was found to be the precursor of these crocins and some of them were found to contain rhamnose, never before reported. When crocin profiles from tepals were compared with those from stigmas, clear differences were found, including the presence of new apocarotenoids in stigmas. Furthermore, each species showed a characteristic profile which was not correlated with the phylogenetic relationship among species. While gene expression analysis in tepals of genes involved in carotenoid metabolism showed that phytoene synthase was a key enzyme in apocarotenoid biosynthesis in tepals. Expression of a crocetin glucosyltransferase, previously identified in saffron, was detected in all the samples. The presence of crocins in tepals is compatible with the role of chromophores to attract pollinators. The identification of tepals as new sources of crocins is of special interest given their wide range of applications in medicine, cosmetics and colouring industries.

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“…Similarly, Dufresne et al (1999) in experiments with C. sativus cell suspensions supplemented with crocetin detected the presence of more-polar crocetin glucosides as major products, which were not detected in stigma tissue. However, crocetin glucosides with more glucose molecules than those detected in C. sativus stigmas have been found in Crocus neapolitanus stigmas (Rychener et al 1984), suggesting that in planta the GTase enzyme is able to form long glucose chains attached to the crocetin molecule, similar in length and complexity to the crocetin glucosyl esters regulated by other enzyme activities, such as degrading enzymes.…”

Section: Discussionmentioning

confidence: 97%

Glucosylation of the saffron apocarotenoid crocetin by a glucosyltransferase isolated from Crocus sativus stigmas

Rubio-Moraga¹,

Nohales²,

Pérez³

et al. 2004

Planta

132

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Saffron, the dry stigma of Crocus sativus L., is considered to be the world's most expensive spice. Three major apocarotenoids--crocin, crocetin and picrocrocin--are responsible for the colour and bitter taste of saffron. The final step in the biosynthesis of the 20-carbon esterified carotenoid crocin is the transformation of the insoluble crocetin into a soluble and stable storage form by glucosylation. These glucosylation reactions are catalysed by glucosyltransferases (GTases) that play a crucial role in natural-product biosynthesis. Using degenerate primers designed to match the plant secondary product GTase (PSPG) box we cloned two cDNAs, UGTCs2 and UGTCs3, from C. sativus stigmas that encode putative polypeptides of 460 and 475 amino acids, respectively. These genes were expressed differentially in saffron tissues. UGTCs2 was mainly expressed in fully developed stigmas, whereas UGTCs3 was mainly expressed in stamens. The UGTCs2 transcript was not detected in the stigma tissue of a Crocus species that does not synthesize crocin, while UGTCs3 and other structural genes for carotenoid biosynthesis were expressed in the stigma of all tested Crocus species. To identify the biochemical function of UGTCs2, the isolated cDNA was expressed in Escherichia coli cells. The recombinant protein UGTCs2 had glucosylation activity against crocetin, crocetin beta-D-glucosyl ester and crocetin beta-D-gentibiosyl ester. These results might suggest that the isolated clone UGTCs2 codes for a saffron crocetin GTase.

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ChemInform Abstract: ISOLATION AND STRUCTURE ELUCIDATION OF NEAPOLITANOSE (O‐β‐D‐GLUCOPYRANOSYL‐(1 → 2)‐O‐(β‐D‐GLUCOPYRANOSYL‐(1 → 6))‐D‐GLUCOSE), A NEW TRISACCHARIDE FROM THE STIGMAS OF GARDEN CROCUSSES (CROCUS NEAPOLITANUS VAR.)

Abstract: Aus der Titelpflanze werden die Carotinoide (I) isoliert.

Cited by 3 publications

References 1 publication

Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus

Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus

Crocins with High Levels of Sugar Conjugation Contribute to the Yellow Colours of Early-Spring Flowering Crocus Tepals

Glucosylation of the saffron apocarotenoid crocetin by a glucosyltransferase isolated from Crocus sativus stigmas

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