Isolation and Purification of Five Phloroglucinol Derivatives From Agrimonia Pilosa Ledeb by Counter-Current Chromatography Using Non-Aqueous Solvent Systems

Abstract

Five non-polar phloroglucinol derivatives, viz. pseudo-aspidin, α-kosin and agripinol A-C were isolated and purified from Agrimonia pilosa Ledeb by semi-preparative counter-current chromatography. The separation was performed by a two-step elution with non-aqueous solvent systems. In the first step, an elution mode of a two-phase solvent system consisting of n-hexane-acetonitrile-dichloromethane-methanol (6:6:0.5:0.5, v/v/v/v) was used. We obtained sample Ι containing three components (47.0mg) and sample ΙΙ containing two components (24.8mg) from crude extract (371.0mg). In the second step, sample Ι was successfully separated by closed-loop recycling mode with a solvent system consisting of n-hexane-acetonitrile-dichloromethane (10:7:3, v/v/v), yielding 17.8mg of pseudo-aspidin, 18.5mg of α-kosin and 6.4mg of agripinol A. The other two compounds-8.7mg of agripinol B and 13.6mg of agripinol C-were obtained from sample ΙΙ in the same manner. All the isolated compounds had a high purity exceeding 95%.