Origin of Indigo of Woad

Epstein, Emily S.; Nabors, Murray W.; Stowe, Bruce B.

doi:10.1038/216547a0

Cited by 55 publications

(39 citation statements)

References 14 publications

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“…From these data, the O-atom at C(3) was the only possible linkage for the carbohydrate portion in 3. So far, the NMR data were in agreement with the hitherto accepted structure of isatan B [5] [10]. However, the NMR data of the carbohydrate unit were inconsistent with a 5-ketogluconate.…”

supporting

confidence: 79%

“…However, Hoogewerff and ter Meulen established in 1900 the structure of indican (1) in Indigofera as −indoxyl-b-d-glucoside× 1 ), and, in the same year, Beijerinck convincingly demonstrated the differing properties of woad-type −indican× and −indoxyl-b-d-glucoside× [4]. On the basis of its chromatographic behavior and the chemical properties of the carbohydrate moiety (and some derivatives), Epstein and co-workers [5] concluded in 1967 that the indigo precursor in woad was −indoxyl-5-ketogluconate× (2) and proposed the name isatan B for this new structure. Subsequent research on woad was based on the assumption of the correctness of this structure, and included studies on the biosynthesis [6] and seasonal variation of isatan B [7] [8], and on woad-processing technologies [9].…”

mentioning

confidence: 98%

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The Elusive Indigo Precursors in Woad (Isatis tinctoria L.) – Identification of the Major Indigo Precursor, Isatan A, and a Structure Revision of Isatan B

Oberthür¹,

Schneider

Graf³

et al. 2004

Chemistry & Biodiversity

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A metabolite-profiling study of shock-frozen leaves of Isatis tinctoria L., an old indigo dye plant and medicinal herb, revealed a complex pattern of indigo-forming compounds with higher polarities than the known indigo precursors isatan B and indican. These highly unstable compounds underwent rapid post-harvest transformation and were not detected in air-dried leaves. The major indigo precursor, named isatan A (4), was isolated by rapid normal-phase and gel chromatography, along with isatan B (3). A full spectral data set of 3 showed that the previous structure assignment as 'indoxyl-5-ketogluconate' has to be revised to 1H-indol-3-yl beta-D-ribohex-3-ulopyranoside. Isatan A (4) was identified as 1H-indol-3-yl 6'-O-(carboxyacetyl)-beta-D-ribohex-3'-ulopyranoside. In aqueous solution, glycosides 3 and 4 occur as hydrates and undergo rapid hydrolysis under very mild acidic or basic conditions.

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supporting

confidence: 79%

mentioning

confidence: 98%

The Elusive Indigo Precursors in Woad (Isatis tinctoria L.) – Identification of the Major Indigo Precursor, Isatan A, and a Structure Revision of Isatan B

Oberthür¹,

Schneider

Graf³

et al. 2004

Chemistry & Biodiversity

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“…The pathway from D-glucose involves an oxidation of carbon-I of the sugar, an epimerization of carbon-5, and retention of the primary alcohol function at carbon-6. New information pertinent to this pathway is found in a report that describes a naturally occurring derivative of 5-keto gluconate (2) and also in the observation that carbons 1 through 4 of L-ascorbic acid are converted to (+)-tartaric acid in grape berries (21).…”

Section: Baig Kelly and Loewusmentioning

confidence: 99%

l-Ascorbic Acid Biosynthesis in Higher Plants from l-Gulono-1, 4-lactone and l-Galactono-1, 4-lactone

1970

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Detached bean (Phaseolus vulgaris) and strawberry (Fragaria) fruits fed L-gulono-1,4-lactone or L-galactono-1,4-lactone convert this compound, in part, to L-ascorbic acid. When L-galactono-1, 4-lactone is given as a 0.25% solution to detached bean shoots, the ascorbic acid content is tripled in less than 10 hours. L-Gulono-1,4-lactone is only 5 to 10% as effective as its epimer. Experiments with specifically labeled L-gulono-I,A4-lactone and L-galactono-l, 4-lactone prove that conversion is direct. Ascorbic acid is labeled at the same carbon as its precursor.A method is described for preparation of L-galactono-1 , 4-lactone-2-_4C from myo-inositol-2-14C. This method can be extended to the preparation of L-ascorbic acid-2-14C on the basis of results obtained in the present study.During the conversion of an uronic acid ester or lactone to ascorbic acid in higher plants, reduction of carbon-I precedes the oxidative step (6,15 MATERIALS AND METHODSPreparation of L-Galactono-1,4-lactone-2-'4C. myo-Inositol-2-14C is readily converted to D-galacturonic acid-5-'4C in detached ripening strawberries (13). In this study, three ripening strawberries (5 g) were administered myo-inositol-2-14c (2 j,c, 0.5 Aimole in 0.1 ml of water) through freshly severed stems. Label was taken up by the berries in about 2 hr. After 24 hr, berries were ground in 70% ethanol (v/v), and the insoluble residue was washed with fresh portions of solvent until all of the soluble 14C was removed. The residue was hydrolyzed with Pectinol R-10 (Rohm and Haas' commercial pectinase) and D-galacturonic acid (14 mg, containing 21% of the "C supplied) was recovered by procedures already described (13). The labeled D-galacturonic acid was converted to its sodium salt and was reduced to the corresponding L-galactonate with sodium borohydride. Recovery of the free acid was achieved by placing the borohydride reaction mixture (after destroying excess borohydride with formic acid) on a column of Dowex 1 exchange resin (formate form) and then by eluting with a formic acid gradient (13). The free acid was converted to its 1,4-lactone by flash evaporation from glacial acetic acid and finally, by heating the residue to 60 C under reduced pressure. A portion of the lactone was converted to its trimethylsilyl ether, and was found to have the same retention time on SE-30 and OV-1 gas chromatographic columns as an authentic sample of tetrakis-O-trimethylsilyl-L-galactono-1 ,4-lactone (9). The final product had a specific radioactivity of 6 ,uc per mmole.Preparation of L-Gulono-1,4-lactone-1-14C and -6-14C. DGlucuronic acid-6-"4C and-1-"4C, respectively, were converted to sodium salts, were reduced to L-gulonic acids, were purified and lactonized as described above. The labeled D-glucuronic acids used in this preparation had been purified previously (20).Final specific radioactivity of L-gulono-1 ,4-lactone-

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“…18 The use of indigo as a textile dye dates back to the Bronze age ( 7000). 26,27 In temperate climates, woad (Isatis tinctoria), has served as its source. The woad industry declined in the sixteenth century because of competition from indigo produced from the tropical plant Indigofera tinctoria and collapsed in the nineteenth century following the chemical synthesis of indigo by Adolf von Baeyer in 1878.…”

Section: Introductionmentioning

confidence: 99%

Blue natural organic dyestuffs—from textile dyeing to mural painting. Separation and characterization of coloring matters present in elderberry, logwood and indigo

et al. 2006

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Natural dyestuffs used for painting or dyeing of textiles are complex mixtures of compounds of various chemical properties. Proper identification of the dye used by a painter and, even better, its origin is possible only when its compositional 'fingerprint' can be evaluated. For this reason gradient program for liquid chromatographic separation of 16 color compounds--components of natural blue dyes: elderberry, logwood and indigo--has been developed. Two detector systems were used simultaneously: UV-Vis spectrophotometry (at 280, 445, 520 and 600 nm) and ESI mass spectrometry (positive and negative SIM mode). It was found that fragmentation observed in ESI-MS is affected not only by ion source parameters, but also by chromatographic conditions, especially in case of the less stable substances: cyanidin glucosides, tannic acid, rutin and hematoxylin. Examination of characteristic dissociation pathways of the compounds under investigation after direct admission into ion source or after chromatographic separation allowed to select proper ions for SIM detection and to develop novel and efficient reversed phase high performance liquid chromatographic (RP-HPLC)-UV-Vis/ESI-MS method for the analysis of natural blue dyes. The procedure was successfully applied for identification of indigotin and carminic acid-main colorants extracted from a fiber taken from the blue-red 'Italian' tapestry (the collection of the National Museum in Warsaw, Poland).

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Origin of Indigo of Woad

Cited by 55 publications

References 14 publications

The Elusive Indigo Precursors in Woad (Isatis tinctoria L.) – Identification of the Major Indigo Precursor, Isatan A, and a Structure Revision of Isatan B

The Elusive Indigo Precursors in Woad (Isatis tinctoria L.) – Identification of the Major Indigo Precursor, Isatan A, and a Structure Revision of Isatan B

l-Ascorbic Acid Biosynthesis in Higher Plants from l-Gulono-1, 4-lactone and l-Galactono-1, 4-lactone

Blue natural organic dyestuffs—from textile dyeing to mural painting. Separation and characterization of coloring matters present in elderberry, logwood and indigo

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