Bioactive constitutents from the stems of Annona montana.

Three structurally related acid amides, N-trans-feruloyltyramine (1), N-p-coumaroyltyramine (2), and N-trans-caffeoyltyramine (3), one lignan, (-)-syringaresinol (4), one aromatic aldehyde, syringaldehyde (5), and two steroids, beta-sitosterol and beta-sitosterol-beta-D-glucoside were isolated from the stem parts of Annona montana (Annonaceae). N-trans-Caffeoyltyramine (3) is a new natural compound. These compounds and their acetate derivatives were subjected to the antiplatelet aggregation and cytotoxicity bioassay where some of them showed significant activities.