Sesquiterpenes and diterpenes from Ambrosia arborescens

Six compounds, eudesm-11(13)-en-4beta,9beta-diol, 15R,16-dihydroxy-3-oxoisopimar-9(11)-ene, 15S,16-dihydroxy-3-oxoisopimar-9(11)-ene, 1alpha-hydroxy-7-oxo-iso-anhydrooplopanone, 10alpha-hydroxy-11,13-dihydro-5-epi-psilostachyin, and 4beta-hydroxypseudoguaian-12,6-olide 4-O-beta-d-glucopyranoside, together with 12 known sesquiterpenes, were isolated from the leaves of Ambrosia arborescens. Structures were elucidated by 1D and 2D NMR spectroscopy including 1D-TOCSY, DQF-COSY, 2D-ROESY, HSQC, and HMBC experiments, as well as by ESI mass spectrometry. The absolute configuration of the 15,16-diol moiety in 15R,16-dihydroxy-3-oxoisopimar-9(11)-ene and 15S,16-dihydroxy-3-oxoisopimar-9(11)-ene was determined using Snatzke's method. All compounds were evaluated for antiproliferative activity.