Studies on the constituents of Umbelliferae plants. XVI. Isolation and structures of three new ligustilide derivatives from Angelica acutiloba.

Abstract

Three new ligustilide derivatives (3-5) were isolated from the crude drug toki, the dried roots of the Umbelliferae plant Angelica acutiloba, together with a known ligustilide dimer, levistolide A (2), and four known oxygenated ligustilide derivatives, senkyunolide E (6), senkyunolide F (7), senkyunolide H (8) and senkyunolide I (9). Compound 3 was shown to be the angeloyl ester of 7. Compounds 4 and 5, designated tokinolide A and tokinolide B, are dimeric ligustilide derivatives with Diels-Alder-type (5) and cyclobutane-type (4) cyclization systems, respectively. The occurrence of compounds 2 to 9 in a fresh A. acutiloba sample was confirmed.