cis-Clerodane diterpene lactones from Amphiachyris dracunculoides. 2

Nine cis-clerodane lactones, amphiacrolides E (1), F (2), G (3), H (4), I (5), O (6), and P (7) and amphiacric acids A (9) and B (8) were isolated from the ethanolic extract of the aerial parts of Amphiachyris dracunculoides, and their structures were established by physical methods. High-field 1D and 2D NMR techniques were used to make complete assignments for the 1H- and 13C-NMR spectra. Amphiacrolides O (6) and P (7) are α-L- arabinopyranosyl ester glycosides of the aglycon amphiacric acids B (8) and A (9), respectively. Amphiacrolides G (3), H (4), and O (6) were reported earlier from Gutierrezia texana; the others are new natural products.