Ferulsinaic acid, a sesquiterpene coumarin with a rare carbon skeleton from Ferula species

Fractionation of methylene chloride extracts of the resin of Ferula vesceritensis and F. sinaica afforded three new sesquiterpene coumarins and a new glucose derivative. One of them was a sesquiterpene with a rare carbon skeleton. The structures of these compounds were determined by extensive NMR studies, including DEPT, COSY, NOE, HMQC, and HMBC.