Analysis of the ethanolic extract of the bark from Parapiptadenia rigida resulted in the isolation of the new catechin derivatives 4',3''-di-O-methylapocynin-D (10), 4',3''-di-O-methylapocynin-B (11), epigallocatechin-3-O-ferulate (8), and 4'-O-methylepigallocatechin-3-O-ferulate (9) and the
Structure elucidation and conformation analysis of four proanthocyanidins isolated from the bark of Parapiptadenia rigida were performed by two-dimensional NMR spectroscopy, HRESIMS, CD, and molecular mechanics (MM+) force field calculations. The known prodelphinidin,