Abstract: In order to obtain Atype oligomeric procyanidins from litchi pericarp with higher purity,C18 silica gel column was used to optimize the traditional preparation process,which was purified and enriched by using AB-8 macroporous resin.According to the component analysis,HPLC and LC-MS identification of litchi pericarp oligomeric procyanidins (LPOPC) prepared by C18 silica gel,the total phenol content of LPOPC was up to 940±123 mg/g,in which (-)-epicatechin monomer,A-type procyanidin dimer and trimer played an important role,occupying 44.86%,36.02% and 9.86%,respectively.The average polymerization degree of the new LPOPC was about 1.62.Consequently,the known A-type procyanidin oligomers,such as procyanidin A2 and trimer,epicatechin (4β→8,2β→O→7)-epicatechin-(4β→8)-epicatechin,can be isolated from the LPOPC more efficiently by Toyopearl HW-40s column.In addition,the isobologram analysis suggested that the purified A-type procyanidin dimer and trimer all possessed strong radical scavenging capacities,and showed synergistic antioxidant effect.

Key words: litchi pericarp, A-type procyanidin oligomer, C18 silica gel, antioxidant