Plant 392

Carthamus species (Asteraceae)


Until the development of twentieth-century aniline dyes, the thistle-like, annual safflower was an important dye plant in Asia and North Africa. Safflower, naturally distributed from south-west to Central Asia, appears to have originated in cultivation through domestication of a wild, weedy species common throughout the region.

The deep orange-red petals of the safflower contain low concentrations of pigments. Yellow pigments are unique, water-soluble flavonoids; the red pigment is mainly water-insoluble carthamin. Mature flower heads are harvested, dried and the intricate process of pigment extraction begins. To stain one kilogramme of cotton bright crimson, the flowerheads from up to five hectares of safflower must be harvested.

Prolonged steeping of the flowers in acidified water removes the yellow pigments that are used to dye wool, silk and cotton. The remaining floral pulp is shaped into blocks and dried for storage or mixed with soda ash to dissolve the carthamin. Red carthamin, precipitated from this alkaline solution by adding acid, is used to dye fibres or incorporated into paints and cosmetics. These processes require careful control if the best quality pigments are to be extracted. Consequently, the skills of safflower farmers and dyers are crucial for profitable dye production.

Safflower pigments have been used since antiquity to colour textiles, cosmetics and food. Safflower dye has been identified in Mesopotamian cuneiform inscriptions and Egyptian textiles approximately 4,000 years old. Garlands of safflower adorn mummies from the Eighteenth Dynasty, whilst its fruits were found in Tutankhamen's tomb. Outside Egypt, the oldest-known, scientifically authenticated, examples of safflower dyes are on eighth-century CE Japanese textiles. Geishas used bright red safflower pigment as lipstick, whilst the same pigment, mixed with rice flour, was in Japanese printing ink. In Britain, safflower’s red dye stained the cotton tape used to tie-up legal briefs, giving us the phrase 'red tape', whilst safflower’s yellow dyes were substitutes for true saffron, giving the plant its other common names, bastard or dyer's saffron.

Safflower is also used as a source of vegetable oil. In Syria, there is evidence safflower was grown for oil production at least 7,000 years ago, probably for cooking and lighting. Like sunflower, safflower fruits yield unsaturated oils, rich in linoleic and oleic acids. There are two types of safflower, one rich in oleic acid and the other rich in linoleic acid; the former is used for human food, the latter for industrial purposes, such as paint manufacture and biodiesel production.

Chapman MA et al. 2010. Population genetic analysis of safflower (Carthamus tinctorius; Asteraceae) reveals a Near Eastern origin and five centers of diversity. American Journal of Botany 97: 831-840.

Clementi C et al. 2014. Carthamus tinctorius L.: a photophysical study of the main coloured species for artwork diagnostic purposes. Dyes and Pigments 103: 127-137.

Dajue L and Mündel H-H 1996. Safflower. Carthamus tinctorius L. IPK and IPGRI.

Stephen Harris