Diterpenes and Diterpene Glucosides from <i>Phlogacanthus curviflorus</i>

Abstract

Abstract magnified image The four new diterpene and diterpene glucosides 1 – 4 , the new bergamotene derivative 5 , and the two new iridoid monoterpenoid glucosides 6 and 7 , together with the eleven known compounds 8 – 18 , were isolated from the EtOH extract of the roots of Phlogacanthus curviflorus. On the basis of chemical and spectroscopic evidence, their structures were identified as (4 α ,5 β ,10 α ,14 α )‐14,19‐dihydroxyabieta‐8,13(15)‐dieno‐16,12‐lactone 19‐( β ‐ D ‐glucopyranoside) (=curvifloruside A; 1 ), (4 α ,5 β ,10 α ,14 α )‐14,19‐dihydroxyabieta‐8,13(15)‐dieno‐16,12‐lactone 19‐[2‐ O ‐(4‐hydroxy‐3,5‐dimethoxybenzoyl)‐ β ‐ D ‐glucopyranoside] (=curvifloruside B; 2 ), (4 α ,5 β ,10 α )‐19‐hydroxy‐14‐oxoabieta‐8,13(15)‐dieno‐16,12‐lactone 19‐[2‐ O ‐(4‐hydroxy‐3,5‐dimethoxybenzoyl)‐ β ‐ D ‐glucopyranoside] (=curvifloruside C; 3 ), 19‐hydroxyjolkinolide E ( 4 ), 9‐oxo‐ α ‐bergamoten‐1‐yl β ‐ D ‐glucopyranoside (=curvifloruside D; 5 ), 6‐deoxyharpagoside (=curvifloruside E; 6 ), and 6‐epiharpagoside (=curvifloruside F; 7 ). This is the first report on sesquiterpene and iridoid glycosides from the Phlogacanthus genus.