Rare biscoumarins and a chlorogenic acid derivative from Erycibe obtusifolia

Four compounds including two symmetrical biscoumarins were isolated from the roots of Erycibe obtusifolia . Their structures were elucidated by spectroscopic methods. Three coumarins, 7,7′-dihydroxy-6,6′-dimethoxy-3,3′-biscoumarin ( 1 ), 7,7′-dihydroxy-6,6′-dimethoxy-8,8′-biscoumarin ( 2 ) and 7-O-[4′-O-(3″,4″-dihydroxycinnamyl)-β- d -glucopyranosyl]-6-methoxycoumarin ( 3 ), and a chlorogenic acid derivative, methyl-3-O-(4″-hydroxy-3″,5″-dimethoxybenzoyl)-chlorogenate ( 4 ) were isolated from the roots of Erycibe obtusifolia along with four known coumarins, scopoletin ( 5 ), scopolin ( 6 ), cleomiscosin A ( 7 ) and cleomiscosin B ( 8 ). Their structures were elucidated by spectroscopic methods. Among them, compounds ( 1 ) and ( 2 ) are rare carbon–carbon linked symmetrical biscoumarins.