Formation and secretion of a new brown benzoquinone by hairy root cultures of Lithospermum erythrorhizon

Hairy roots of Lithospermum erythrorhizon in Murashige-Skoog medium produce a new brown benzoquinone derivative instead of red naphthoquinone (shikonin) derivatives as the main secondary metabolites. The structure of the new quinone was elucidated to be 2-[4-(E-4-hydroxymethyl-3-pentenyl)-furan-2-yl]-1,4-benzoquinone (called hydroxyechinofuran B) based on spectroscopic data. Its biosynthesis may be via geranylhydroquinone, a key biosynthetic intermediate of shikonin.