Tannins and Related Compounds. XCIII. : Occurrence of Enantiomeric Proanthocyanidins in the Leguminosae Plants, Cassia fistula L. and C. javanica L

Proanthocyanidins containing flavan-3-ol (epiafzelechin and epicatechin) units with an abnormal 2S-configuration have been isolated from the pods of Cassia fistula L. and the bark of C. javanica L. (Leguminosae), together with common flavan-3-ols and proanthocyanidins The structures of these compounds have been established on the basis of chemical and spectroscopic evidenve. In addition, the flavan-3-ols and proanthocyanidins obtained from C. fistula have been found to be partly racemic, and the proportions of each enantiomer have beem determined by high-performance liquid chromatography using an optical resolution column.