Lithospermum ruderale: Partial characterization of the principal polyphenol isolated from the roots

Abstract Lithospermic acid from L. ruderale roots is a polyphenolic carboxylic acid with an empirical formula believed to be C 16 H 14 O 7 . The molecule has two 1,2,4-trisubstituted benzene rings, each containing o -dihydroxy groupings; and an olefinic grouping which is conjugated with one of the rings. The last oxygen atom is probably present as a tertiary alcohol. Optical activity indicates that the molecule contains one or more asymmetric centres. The structure of this molecule is discussed.