Diterpenes and diterpene glucosides from Phlogacanthus curviflorus

Abstract

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 (4α,5β, 10α,14α)-14,19-dihydroxyabieta-8,13(15)-dieno-16,12-lactone 19-(β-D-glucopyranoside) (=curvifloruside A; 1), (4α,5β, 10α,14α)-14,19-dihydroxyabieta-8,13(15)-dieno-16,12-lactone 19-[2-O-(4-hydroxy-3,5-dimethoxybenzoyl)-β-D-glucopyranoside] (=curvifloruside B; 2), (4α,5β,10α)-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-a-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. © 2009 Verlag Helvetica Chimica Acta AG.