Biologically Active Macrocyclic Diterpenoids from Chinese Drug “Fáng Féng Cáo” I. Isolation and Structure1

Abstract

Three novel macrocyclic diterpepoids, 4,7-oxycycloanisomelic acid (4), 4-methylene-5-hydroxyovatodiolode (5) and 4-methylene-5-oxoanisomelic acid (6) were isolated from the dried whole plant of the Chinese crude drug Fáng Féng Cáo (Anisomeles indica, Labiatae), together with ovatodiolide (1), 4, 5-epoxyovatodiolide (2) and anisomelic acid (3). The structures of the novel compounds were deduced by the comparison of spectral data with those of known relative compounds. Isolated compounds were subjected to the examination of inhibitory activity of angiotensin converting enzyme, cytotoxic activity and calcium antagonistic activity.