Studies on the constituents of bark of Parameria laevigata Moldenke

One new trimeric proanthocyanidin, epicatechin-(2 beta -->O -->7,4 beta -->6)-epicatechin-4 beta -->8)-epicatechin (5) and two new tetrameric proanthocyanidins, epicatechin-(2 beta -->O -->7,4 beta -->8)-[epicatechin-(4 beta -->6)]-epicatechin-(4 beta -->8)-epicatechin, named as parameritannin A-1 (6), and epicatechin-(2 beta -->O -->5,4 beta -->6)-[epicatechin-(2 beta -->O -->7, 4 beta ,8)]-epicatechin-(4 beta -->8)-epicatechin, named as parameritannin A-2 (7), have been isolated from the bark of Parameria laevigata Moldenke (Apocynaceae) along with the two known dimers, proanthocyanidin A-2 (1) and proanthocyanidin A-6 (2), and two trimers, cinnamtannin B-1 (3) and aesculitannin B (4). These structures were elucidated by spectral and chemical evidence.