''Chrozophora tinctoria'' (commonly known as dyer's croton, giradol, turnsole or dyer's litmus plant) is a plant species native to the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...

, the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's fifth-most populous country, with a population of almost 243 million people, and has the world's second-lar ...

, and

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

.Kew World Checklist of Selected Plant Families
/ref> It is also present as a weed in North America and Australia.

Description

It is an annual, typically found in nutrient-poor ground. It develops a large

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

. The plant is erect and covered with wool-like hairs. The ash-green leaves are alternate. The tiny monecious flowers are grouped in a raceme. The lower, female flowers lack petals and the upper male flowers have five small yellow petals. Pollination is by ants. The fruits are conspicuous and consist of three dark green conjoined spheres. Their surface is decorated with white scales and warty structures. Each sphere contains three seeds, which are propelled away from the plant by the mechanical force of the mature fruit twisting as it opens.

Use for dye

''Chrozophora tinctoria'' produced the blue-purple colorant " turnsole" (also known as katasol or folium ) used in medieval illuminated manuscripts and as a food colorant in Dutch cheese and certain liquors. Its use was mostly as substitute of the more expensive Tyrian purple, the famous dye obtained from Murex molluscs.M. Aceto, E. Calà, A. Agostino, G. Fenoglio, A. Idone, C. Porte, M. Gulmini, On the identification of folium and orchil on illuminated manuscripts, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, http://dx.doi.org/10.1016/j.saa.2016.08.046 The color comes from the plant's fruit, specifically its dry outer coat. The colorant is also obtained from the translucent sap contained in the plant cells when the leaves of the plant are broken off and exposed to the air., s.v. ''Chrozophora tinctoria'' Different shades of blue and purple may also be obtained when the juice extracts are exposed to the vapors emitted from

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

(NH₃), and which in France, during the late 19th century, was produced by applying fresh horse manure and urine to the fabric that was soaked with the plant extract. The plant has historically been used throughout the

Levant The Levant () is an approximate historical geographical term referring to a large area in the Eastern Mediterranean region of Western Asia. In its narrowest sense, which is in use today in archaeology and other cultural contexts, it is ...

to dye clothing. of the plant produces of sap, and with this quantity one is able to dye of fabric rolls. In 2020, an interdisciplinary team of researchers from FCT NOVA, University of Porto and

University of Aveiro The University of Aveiro ( pt, Universidade de Aveiro) is a public university, in addition to providing polytechnic education, located in the Portuguese city of Aveiro. Founded in 1973, it has a student population of approximately 12,500, distri ...

, identified the complex chemical structure of the medieval purple-blue dye extracted from the fruits of ''Chrozophora tinctoria''. The chemical structure of the medieval dye was a mystery until now. The extracts obtained showed a novel blue chemical, chrozophoridine as the main chromophore.

References

{{Taxonbar, from=Q1984236 Chrozophoreae Plants described in 1753 Taxa named by Carl Linnaeus Taxa named by Adrien-Henri de Jussieu Flora of Asia Plant dyes Flora of Malta