Abstract
The roots of Lithospermum erythrorhizon Sieb. and Zucc., (violet root, Japanese name, Shikon) contain shikonin and its esters as purple pigments. The coloring matter of the root of Alkanna tinctoria in Europe is a mixture of the enantiomeric alkannin and its esters. The racemic compound of shikonin and alkannin was named shikalkin by R. Kuhn and H. Brockmann. From ancient times these purple pigments have been well-known as valuable materials having antiinflammatory, antibacterial, antitumor actions, and as ancient purple deys and cosmetics. Here, the history, structural determination, synthesis and pharmacology of shikonin, alkannin, and their derivatives will be reviewed.
