- Degradation of lucidin: New insights into the fate of this natural pigment present in Dyer's madder (Rubia tinctorum L.) during the extraction of textile artefacts
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The complex mixtures of colorants present in different madder species can provide significant information about which plant species or technique was used to dye the fibres of historical textile artefacts, hence, when extracting and analysing colorants from textile artefacts as much of this information as possible should be preserved. Historical textiles are most commonly extracted with 37% hydrochloric acid: methanol: water (2:1:1, v/v/v), but this solvent system hydrolyses dye glycosides and may also induce chemical reactions. One of the primary components in Dyers’ madder (Rubia tinctorum L.) is lucidin primeveroside, but it is rarely seen in artefacts, nor is the corresponding aglycon lucidin. It has been demonstrated that the hydrochloric acid method causes hydrolysis of anthraquinone glycosides to their aglycon counterpart. Herein it is demonstrated that lucidin is not stable in such acidic conditions and degrades rapidly to xanthopurpurin. This is confirmed by HPLC, LC-MS and 1H NMR, which also provide evidence of the mechanism of degradation being a retro-aldol process.
- Ford, Lauren,Rayner, Christopher M.,Blackburn, Richard S.
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- Crystal structures of mollugin and lucidin
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Mollugin was isolated from the extract of Rubia tinctorum roots. Lucidin was obtained by semisynthesis from xanthopurpurin. Mollugin crystallises in space group P-1 (No. 2), a = 8.5857(7), b = 11.473(4), c = 15.024(1) A, α = 77.64(2)°, β = 89.36(1)°, γ = 89.71(2)°, and V = 1445.5(5) A3, lucidin crystallises in space group P2 1/c (No.14), a = 16.800(6), b = 9.637(2), c = 7.073(7) A, β = 98.01(5)°, and V = 1134(1) A3.
- Jegorov, Alexandr,Cvak, Ladislav,Cejka, Jan,Kratochvil, Bohumil,Sedmera, Petr,Havlicek, Vladimir
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- Antifeedant activity of an anthraquinone aldehyde in Galium aparine L. against Spodoptera litura F.
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The insect antifeedant anthraquinone aldehyde nordamnacanthal (1,3-dihydroxy-anthraquinone-2-al) was identified in Galium aparine L., and isolated from the root powder of akane (Rubia akane), a member of the Rubiaceae. Structure-activity relationship (SAR) studies using a series of anthraquinone analogues suggested that the aldehyde group on the anthraquinone was more important than the quinone moiety for antifeedant activity against the common cutworm (Spodoptera litura). High levels of nordamnacanthal were found in the seed leaf stage and in callus tissue induced from seedlings of G. aparine, but its concentration decreased with plant development. Since these compounds are natural pigments for dying textiles, we also evaluated the antifeedant activity against the carpet beetle (Attagenus japonicus), a textile pest was also evaluated. While nordamnacanthal had strong antifeedant activity against the common cutworm, it did not show any antifeedant activity against the carpet beetle. The most effective antifeedant against the carpet beetle was the major constituent in the extract of R. trictorum, lucidin- 3 - O-primeveroside, a food pigment. 2002 Elsevier Science Ltd. All rights reserved.
- Morimoto, Masanori,Tanimoto, Kumiko,Sakatani, Akiko,Komai, Koichiro
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p. 163 - 166
(2007/10/03)
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- Anthraquinones from Neonauclea calycina and their inhibitory activity against DNA topoisomerase II
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In a series of searches for DNA topoisomerase II inhibitors from naturally occurring compounds, a wood extract of Neonauclea calycina MERR. (Rubiaceae) showed a moderate effect in vitro. Purification of the extract resulted in the isolation of seven known anthraquinones. The structures were characterized as damnacanthal, rubindin 1-methyl ether, nordamnacanthal, morindone, damnacanthol, lucidin 3-O-primeveroside and morindone 6-O- primeveroside by spectral analysis, respectively. Damnacanthal and morindone showed an intensive inhibitory effect against topoisomerase II (IC50: 20 μg/ml and 21 μg/ml).
- Tosa, Hideki,Iinuma, Munekazu,Asai, Fujio,Tanaka, Toshiyuki,Nozaki, Hiroshi,Ikeda, Shougo,Tsutsui, Ken,Tsutsui, Kimiko,Yamada, Masashi,Fujimori, Shiho
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p. 641 - 642
(2007/10/03)
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- BIOSYNTHESIS OF ANTHRAQUINONES AND RELATED COMPOUNDS IN GALIUM MOLLUGO CELL SUSPENSION CULTURES
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From Galium mollugo cell suspension cultures, 1,4-dihydroxy-3-prenyl-2-naphtholic acid methyl ester diglucoside was isolated along with anthraquinones and mollugin.Production of the diglucoside was much increased by administering 2-succinylbenzoate to the cultures.The incorporation of 2-succinylbenzoate into lucidin-3-primeveroside, mollugin and the diglucoside in the mode so far proposed for rubiaceous anthraquinones was verified by administration of 13C-labelled 2-succinylbenzoate to the cell cultures.Key Word Index - Galium mollugo; Rubiaceae; lucidin-3-primeveroside; 1,4-dihydroxy-3-prenyl-2-naphthoic acid methyl ester diglucoside; biosynthesis; cell suspension culture; 13C NMR; mass spectrometry.
- Inoue, Kenichiro,Shiobara, Yoshinori,Nayeshiro, Hidekazu,Inouye, Hiroyuki,Wilson, Graham,Zenk, Meinhart H.
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p. 307 - 312
(2007/10/02)
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