Prota 3: Dyes and tannins/Colorants et tanins
Journ. Linn. Soc., Bot. 20: 162 (1883).
Origin and geographic distribution
Danais ligustrifolia is endemic to Madagascar.
The roots of Danais ligustrifolia are one of the main sources of orange to red dyes, used in traditional textiles in Madagascar to dye raffia and silk. Red is one of the most important colours in these textiles, for instance in ‘raffia ikats’. Raffia ikats are long pieces of raffia cloth in which some portions of the warp yarns are tied with thick threads to protect the patterns before dyeing the yarn; successive patterns of tying and dyeing in different dye baths create multicoloured designs, usually in the natural ivory colour of the raffia fibre, red, orange or pink, two shades of blue, black and yellow or green. Red vegetable dye is also very important in the ‘lamba mena’, fine textiles used as shrouds. Before dyeing it with the root of Danais ligustrifolia, the fibre is prepared by boiling it in water to which ash is added, then it is washed and dried. The roots of Danais ligustrifolia are pounded and put into almost boiling water; usually 2 parts of root with 3 parts of water make up the total volume of the dye bath. Then the fibre is added, submerged and left for 1–6 hours, depending on the intensity of the colour wanted. Subsequently the dyed fibre is washed again and dried. Many Danais species also have medicinal uses in Madagascar and neighbouring islands, the roots being used against herpes and the bark as a febrifuge.
Like other Danais species, the bark and roots of Danais ligustrifolia, most probably contain the anthraquinones danain and danaidin, which are the sources of the orange and red dyes obtained from these plants. The leaves of many Danais species contain high proportions of aluminium (up to 1% of the dry matter weight in Danais fragrans (Comm. ex Lam.) Pers.), which can be used as an organic mordant since aluminium salts are the most useful substances employed in dyeing processes, to strengthen and multiply the chemical bonds between textile fibres and most natural dyes.
Liana or climbing shrub, with stems up to 25 m long. Leaves decussately opposite, simple, entire, glabrous; stipules deltoid, c. 2 mm long; petiole 3–10 mm long; blade elliptical to lanceolate-ovate, 3–12 cm × 1.5–4.5 cm, base cuneate, apex acuminate. Inflorescence a usually terminal, pyramidal panicle with cymose branches, up to 14 cm × 10 cm; peduncle up to 3.5 cm long. Flowers bisexual, regular, 5-merous, heterodistylous, fragrant; pedicel up to 1 mm long; calyx tubular with triangular lobes up to 2.5 mm long; corolla tubular, tube funnel-shaped, up to 4.5 mm long, greenish white, hairy in throat, lobes oblong, up to 2 mm long, yellow-orange; stamens included in long-styled flowers, exserted for c. 4 mm in short-styled flowers; ovary inferior, globose, c. 1 mm in diameter, style plus stigma 6–8 mm long in long-styled flowers, shorter than corolla tube in short-styled flowers, stigma lobes 2. Fruit a globose capsule c. 3 mm in diameter, thin-walled, glabrous. Seeds c. 1 mm in diameter, dark brown, with a broad, irregularly lacerate wing.
Danais comprises about 25 species, most of them endemic to Madagascar. The genus is closely related to the Madagascan genera Schismatoclada (about 20 species) and Payera (about 10 species), the 3 forming a complex partly fitting in subfamily Rubioideae, and partly in subfamily Cinchonoideae, which makes its systematic position in Rubiaceae still unclear. Danais ligustrifolia closely resembles Danais microcarpa Baker, also endemic to Madagascar, whose leaves are usually smaller. The roots of several other Danais species are similarly used as sources of red dyes, the most important species being Danais cernua Baker, Danais rhamnifolia Baker (synonym: Danais chapelieri Drake) and Danais volubilis Baker (synonym: Danais latisepala Homolle). A paste of pounded rootbark of Danais rhamnifolia dyes raffia a dark blood red. With some lemon juice added, the roots of Danais cernua dye a deep red, while those of Danais volubilis dye more orange. Danais cernua is widespread all over Madagascar; its leaves are mostly opposite, but occasionally arranged in whorls of 3 and measure up to 9 cm × 4 cm. When its tissue is damaged an unpleasant foetid odour is emitted, possibly caused by the iridoid glycoside paederoside. Danais volubilis, endemic to Madagascar, has its leaves always in whorls of 3 (or sometimes 4) and has larger flowers and fruits. Danais rhamnifolia is endemic in eastern Madagascar and is closely related to Danais microcarpa and Danais ligustrifolia. It has larger, membranous leaves, larger inflorescences with flowers that have typically thin, filiform corolla tubes. Flowering of Danais ligustrifolia is mainly in March–June, fruiting in October–June.
Danais ligustrifolia occurs in the eastern lowland rainforest of Madagascar, sometimes in valleys and ravines, from sea-level up to 1000 m altitude.
Genetic resources and breeding
Danais ligustrifolia is rather widespread in Madagascar and does not seem to be in danger of genetic erosion as long as its habitat is not endangered.
Danais ligustrifolia and other Danais species represent interesting sources of orange to red dyes, with the aluminium present in the leaves functioning as a mordant. In Madagascar, several development programmes are presently promoting the renewed use of natural dyes, including the reds from various Danais species, in the production of raffia, silk and mohair textiles, inspired by traditional textiles and created by young Malagasy fashion designers. Possibilities for cultivation and chemical compositions deserve further investigation.
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• Decary, R., 1946. Plantes et animaux utiles de Madagascar. Annales du Musée Colonial de Marseille, 54e année, 6e série, 4e volume, 1er et dernier fascicule. 234 pp.
• Puff, C. & Buchner, R., 1994. Revision of Danais Vent. (Rubiaceae) in Madagascar and the Comores. Bulletin du Muséum National d’Histoire Naturelle, séries 4, Section B, Adansonia 16: 11–64.
• Buchner, R. & Puff, C., 1993. The genus complex Danais-Schismatoclada-Payera (Rubiaceae). Character states, generic delimitation and taxonomic position. Bulletin du Muséum National d’Histoire Naturelle, séries 4, Section B, Adansonia. 15: 23–74.
• Jansen, S., Dessein, S., Piesschaert, F., Robbrecht, E. & Smets, E., 2000. Aluminium accumulation in leaves of Rubiaceae: systematic and phylogenetic implications. Annals of Botany 85: 91–101.
• Jansen, S., Watanabe, T., Dessein, S., Smets, E. & Robbrecht, E., 2003. A comparative study of metal levels in leaves of some Al-accumulating Rubiaceae. Annals of Botany 91: 657–663.
Correct citation of this article:
Jansen, P.C.M., 2005. Danais ligustrifolia Baker In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.