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'' (lithospermum root or ''Lithospermi Radix'') is a Chinese herbal medicine with various antiviral and biological activities, including inhibition of human immunodeficiency virus type 1 (HIV-1).

The genome sequence of ''Lithospermum erythrorhizon'' is sequenced and has facilitated the discovery of a putative retrotransposition-derived duplication event that produced a 4-hydroxybenzoate geranyltransferase gene involved in alkannin biosynthesis.

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.

Uses

It has been cultivated in Japan since the Nara period for its root, which can be used for herbal medicine and to make dyes.

Before the introduction of synthetic dyes to Meiji period Japan, the roots were commonly used as a dyestuff for luxury textiles, typically high-end kimono and . The process of extracting purple dyestuff from the roots was an exceedingly long, complex and time-consuming process, necessitating its relatively high expense:

For a deep purple, up to 50 dips could be needed. dye loses colour remarkably fast, literally as the fibers are being dipped, meaning it was often used for (ombré) dying, and the resulting colour was varied and uneven, with each strand a slightly different shade.

One Japanese word for the plant, ''murasaki'' (紫), 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'' (紫色). Additional terms were used for specific shades of purple within this range, particularly during the Heian period; names such as ("pale purple") and ("light purple") formed important distinctions when dressing in specifically-layered clothing, and could also indicate (typically high) rank.

The dyes made from its root also had other names, such as ''shikon'' (紫根), 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.

See also

* List of kampo herbs

References

{{Taxonbar, from=Q15592453

erythrorhizon
Plants described in 1846