Chika Mouri

Identification of anthraquinone markers for distinguishing Rubia species in madder-dyed textiles by HPLC

AbstractThe anthraquinone components of the roots of various species of madder (Rubia spp.) have been used for millennia as red colorants in textiles, carpets and other objects. Although many species of Rubia are known, only a few of them have been used widely for dyeing. Furthermore, though nearly 70 anthraquinones have been found in Rubia species, only a few of these occur consistently at relatively high levels. Knowledge of the plant dyestuffs is helpful for establishing the location of production, production method and/or history of the dyed object. Using plant material and dyed textile fibers obtained from a number of sources, and HPLC with photodiode array and mass spectrometric detection for analysis, we have been able to identify marker anthraquinones that permit differentiation of the more common species of madder used for dyeing in Eurasia. Textiles dyed with all of the species examined contain varying amounts of purpurin, but only those dyed with Rubia akane contain large amounts of 6-hydroxyrubiadin (1,3,6-trihydroxy-2-methylanthraquinone) or its glycosides. Textiles dyed with R. tinctorum contain primarily alizarin, whereas those dyed with R. cordifolia and R. peregrina contain mostly purpurin, munjistin and pseudopurpurin, but little or no alizarin or 6-hydroxyrubiadin. The latter two species cannot reliably be distinguished from each other, however. The plants themselves often contain glycoside precursors not usually seen in the dyed materials. FigureThe analysis, based on HPLC retention time, UV/Visible spectra and molecular mass, of ancient madder (Rubia)-dyed textile extracts can identify the species used for dyeing.

The relationship between growth of the aerial part and alkaloid content variation in cultivated Aconitum carmichaeli Debeaux

Processed root of aconite, Aconitum carmichaeli Debeaux—known as bushi in Japan—is indispensable for treating diseases among elderly persons in Japanese and Chinese traditional medicine. Its active component is bushi diester alkaloid (BDA), which consists of aconitine (ACO), mesaconitine (MES), hypaconitine (HYP), and jesaconitine (JES). Since an overdose of BDA results in severe side effects, the BDA content should be within safe limits. However, the BDA content of raw aconite root, even that produced by standard cultivation procedures, varies greatly. In this study, to clarify the cause of BDA variation, we examined the weight and BDA content of each part of cultivated A. carmichaeli: the aerial part, the mother tuberous root (MT), the daughter tuberous root (DT), and the rootlet (RL). We found the following positive relationships: between aerial part weight and DT weight, aerial part weight and BDA content in stem of apex, and BDA content in stem of apex and total BDA of DT attached to the plant. Furthermore, DT belonging to a higher weight group showed less BDA content variation. In addition, BDA of DT and those of MT and RL differ in both content and composition. In conclusion, it was suggested that the weight or the size of the aerial part was a good marker for monitoring BDA content and its variation in the tuberous root, and it was found to be desirable to prevent mixing MT and RL at harvest.

Identification and partial characterization of C-glycosylflavone markers in Asian plant dyes using liquid chromatography-tandem mass spectrometry.

Flavonoids in the grasses (Poaceae family), Arthraxon hispidus (Thunb.) Makino and Miscanthus tinctorius (Steudel) Hackel have long histories of use for producing yellow dyes in Japan and China, but up to now there have been no analytical procedures for characterizing the dye components in textiles dyed with these materials. LC-MS analysis of plant material and of silk dyed with extracts of these plants shows the presence, primarily, of flavonoid C-glycosides, three of which have been tentatively identified as luteolin 8-C-rhamnoside, apigenin 8-C-rhamnoside and luteolin 8-C-(4-ketorhamnoside). Two of these compounds, luteolin 8-C-rhamnoside (M=432), apigenin 8-C-rhamnoside (M=416), along with the previously known tricin (M=330) and several other flavonoids that appear in varying amounts, serve as unique markers for identifying A. hispidus and M. tinctorius as the source of yellow dyes in textiles. Using this information, we have been able to identify grass-derived dyes in Japanese textiles dated to the Nara and Heian periods. However, due to the high variability in the amounts of various flavonoid components, our goal of distinguishing between the two plant sources remains elusive.

Preliminary Studies Toward Identification of Sources of Protoberberine Alkaloids used as Yellow Dyes in Asian Objects of Historical Interest

Abstract The protoberberines bright yellow alkaloids that have been used for centuries in Chinese and other traditional medicines and also as dyes for textiles and paper. The most frequently cited source for protoberberine dyes is the Amur cork tree (phellodendron amurense). However, many plants contain protoberberines, and, as shown here, the analysis of dyed objects often permits identification of plant types, which sheds light on the resources available to early dyers. In this study, representatives of five genera (Berberis, coptis, Fibraurea, Mahonia, phellodendron) of protoberberine-yielding plants were analyzed, all of which have been reported as having been used in Asia as sources of yellow colorants, using high-performance liquid chromatography (HPLC) with diode array and mass spectrometric detection. It is shown that their contents of berberine, palmatine, jatrorrhizine and other protoberberines are distinctive enough to allow them to be distinguished from one another. As a result, analysis of the dyes used in several historical objects allows conclusions to be drawn as to the plant source of the dye. Knowledge of the type of colorant used in an object is important for its conservation because the protoberberine alkaloids, as a class, are both very water-soluble and relatively unstable (among yellow dyes) to light.

Analysis of dyes in textiles from the Chehrabad salt mine in Iran

This study describes the analysis of dyes from three textile specimens associated with human remains found in the Chehrabad salt mine in northwestern Iran dating to 2000 ± 400 years BP. They are unique for this part of the world not only because of their age, but because they represent textiles used by common people (salt miners) as opposed to funerary garments of the wealthy. Samples of yarns from these specimens were extracted and analyzed by high performance liquid chromatography with diode array and mass spectrometric detection. The red dye was obtained from madder (specifically Rubia tinctorum L.), and the blue was from an indigo plant, probably woad (Isatis tinctoria L.), both of which are known in Iran. Two yellow, plant-derived, flavonol dyes were found. The first seems to be from a species of tamarisk (Tamarix sp.), whereas the second, found in both yellow and green yarns, is from a so-far unidentified plant. This work represents the first detailed study of these salt mine dyes, and the first evidence for the use of tamarisk as a dyestuff.