Separation of Madecassoside and Madecassic Acid Isomers by High Performance Liquid Chromatography Using beta-Cyclodextrin as Mobile Phase Additive

摘要

An improved HPLC method for the separation of madecassoside isomers(madecassoside and asiaticoside-B)has been developed.The isomers can be separated with high resolution from extracts of Centella asiatica by HPLC using beta-cyclodextrin as a mobile phase added on a C18 column.The result shows that the isomers can be separated with a mobile phase consisting of methanol:water(50:50,v/v)with 4 mmol/L beta-CD.To elucidate the mechanism of the separation of madecassoside and asiaticoside-B,this paper studied the separation of their aglycon parts(madecassic acid and terminolic acid),another pair of isomers.The isomers can also be separated with high resolution with a mobile phase consisting of methanol:water(65:35,v/v)with 4 mmol/L beta-CD and the pH of the mobile phase was adjusted to 4.The paper also studied the separation of the two isomers by HPLC using alpha-CD and Glucosyl-betalpha-CD as a mobile phase additive in order to elucidate the mechanism of the separation process.