Preparation of Bioactive Iridoid Glycosides from the Stem Bark of Catalpa ovata Using High-Speed Counter-Current Chromatography

A preparative high-speed counter-current chromatography (HSCCC) method was developed for the isolation of the major iridoid glycosides from the stem bark of Catalpa ovata (Bignoniaceae). A biphasic solvent system comprising EtOAc/BuOH/water (10:1:10, v/v) was selected as the optimal condition for purification, leading to the isolation of catalposide (1, 3.9 mg, 98.1% purity) and 6-O-trans-feruloyl catalpol (2, 12.2 mg, 99.2% purity) from 100 mg of a 70% EtOH crude extract. The structures of the isolates were identified by the ¹H- and ¹³C-NMR spectroscopy and HR-MS, and their purities were determined by HPLC-ELSD analysis. As 6-O-trans-feruloyl catalpol (2) has recently been proposed as a promising therapeutic agent for liver regeneration, the optimized HSCCC conditions may serve as an efficient preparative strategy for this bioactive compound.