Tigloylshikonin, a New Minor Shikonin Derivative, from the Roots and the Commercial Root Extract of Lithospermum erythrorhizon

Tigloylshikonin, a new shikonin derivative esterified with tiglic acid ((E)-2-methylbut-2-enoic acid), was isolated as a minor pigment from a food colorant "Shikon color," a commercial root extract from Lithospermum erythrorhizon SIEBOLD et ZUCCARINI The structure of tigloylshikonin was elucidated using H-1, C-13, the difference nuclear Overhauser effect (NOE), and 2D NMR techniques Its stereochemistry was determined by chiral-phase HPLC analysis Tigloylshikonin was also found in the roots of L erythrorhizon, which indicated that this new shikonin derivative is a typical component of naphthoquinone pigments in the roots of L erythrorhizon