Studies on constituents from Chamaecyparis pisifera and antibacterial activity of diterpenes

In the course of our research for biologically active constituents from coniferous plants, a chromone derivative (1) and an abietane derivative (2) were isolated along with several diterpenes from Chamaecyparis pisifera. Structures of the new compounds were determined to be 5,7-dihydroxy-2-(1-acetyl-2-methoxycarbonylethyl)-chromone and rel-(8R,10R,20S)-8,10,20-trihydroxy-9(10 --> 20)-abeo-abieta-9,13-dien-12-one by means of spectral methods including two-dimensional NMR experiments. Some of these abietane-type compounds isolated from this plants showed antibacterial activity against the gram-positive bacteria Staphylococcus aureus and Bacillus subtilis.