1955 Volume 75 Issue 2 Pages 219-221
Anthraquinone pigments were isolated from Damnacanthus major Sieb. et Zucc., D. major Sieb. et Zucc. var. parvifolius Koidz., and D. indicus Gaertner fil. var. microphyllus Makino (Rubiacea family), and were designated as follows: Damnacanthal (m.p. 208°), juzunal (m.p. 248°), damnacanthol (m.p. 288°), damnidin (m.p. 180°), and a neutral substance (m.p. 160°). Of these, damnacanthal is identical with the substance, C16H10O5 (B), isolated by Perkin from Morinda umbellata L. It is an anthraquinone containing α-methoxyl and is saponified by sulfuric acid or alkali to form nordamnacanthal, m.p. 218°, which is the decarboxylation product of m.p. 218° obtained by Perkin. Heating of damnacanthal with alkali yielded purpuroxanthin.