Analysis of shikonin/alkannin derivatives in root extracts. Methanol extracts of L. erythrorhizon and E. plantagineum were subjected to HPLC with a chiral column, and each representative chromatogram is shown. Labeled compounds: 1, β-hydroxyisovalerylalkannin; 2, β-hydroxyisovalerylshikonin; 3, acetylalkannin; 4, acetylshikonin; 5, isobutyrylshikonin; 6, α-methyl-n-butyrylalkannin; 7, isovalerylalkannin; 8, α-methyl-n-butyrylshikonin; 9, isovalerylshikonin.