Study on triterpenoid acid constituents from the surface layer of Poria cocos

OBJECTIVE To study the triterpenoid chemical constituents from the surface layer of Poria cocos. METHODS The compounds were isolated and purified from extracts of surface layer of P. cocos by column chromatography and preparation HPLC methods,and the structures were identified by spectroscopic methods. RESULTS Eleven compounds were isolated,and their structures were identified as poricoic acid A( Ⅰ),poricoic acid B( Ⅱ),poricoic acid AM( Ⅲ),pachymic acid( Ⅳ),dehydroeburiconic acid( Ⅴ),dehydrotrametenonic acid( Ⅵ),dehydrotrametenolic acid( Ⅶ),eburicoic acid( Ⅷ),3- O- acetyl- 16α- hydroxytrametenolic acid( Ⅸ),3- O- formyl- dehydrotrame- tenolic acid( Ⅹ) and 3- O- formyl- eburicoic acid( Ⅺ). Compound Ⅹ and Ⅺ were isolated from the nature for the first time. CONCLUSION Compound Ⅹ and Ⅺ are artifact products during the isolation by validation experiments.