Lithospermum erythrorhizon


Lithospermum erythrorhizon, commonly called purple gromwell, red gromwell, red-root gromwell and redroot lithospermum, is a plant species in the genus Lithospermum. It is called zǐcǎo in Chinese, jichi in Korean, and murasaki in Japanese.
The dried root of Lithospermum erythrorhizon is a Chinese herbal medicine with various antiviral and biological activities, including inhibition of human immunodeficiency virus type 1.

Biochemistry

The enzyme 4-hydroxybenzoate geranyltransferase utilizes geranyl diphosphate and 4-hydroxybenzoate to produce 3-geranyl-4-hydroxybenzoate and diphosphate. Biosynthetically, alkannin is produced in plants from the intermediates 4-hydroxybenzoic acid and geranyl pyrophosphate. This enzyme is involved in shikonin biosynthesis.
The enzyme geranylhydroquinone 3''-hydroxylase uses geranylhydroquinone, NADPH, H+ and O2 to produce 3-hydroxygeranylhydroquinone, NADP+ and H2O.

Culture

It has been cultivated in Japan since the Nara period for its root, which can be used for herbal medicine and to make dyes.
One Japanese word for the plant, murasaki, inspired the pen name "Lady Murasaki" for the author of The Tale of Genji and is also the source of the general Japanese term for the color purple, murasaki iro.
The dyes made from its root also had other names, such as shikon, but all of them were difficult to work with because of their requirement for an alum-rich mordant and the resulting colors' extreme vulnerability to photobleaching. During the Heian Period, sumptuary laws restricted murasaki-dyed clothing to the Empress and her ladies in waiting.