Preparative separation of isomeric caffeoylquinic acids from Flos Lonicerae by pH-zone-refining counter-current chromatography.

This work concentrates on pH-zone-refining counter-current chromatography of two isomeric dicaffeoylquinic acids, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid along with 3-caffeoylquinic acid, from crude extracts of Flos Lonicerae. The elution sequence of the isomeric dicaffeoylquinic acids, the mixing zone and mechanism of separation are discussed. The separation of 2.136g of the crude sample from Flos Lonicerae yielded two isomeric compounds: 0.289g 3,5-dicaffeoylquinic acid and 0.106g 3,4-dicaffeoylquinic acid plus 0.690g 3-caffeoylquinic acid at a high purity of over 92.9%, 94.2% and 97.5%, respectively.