Additional Antibacterial Diterpenes from the Bark of Juniperus procera

The bark of Juniperus procera yielded the diterpene 7β-hydroxyabieta-8,13-dien-11,12-dione (1) with strong activity against Mycobacterium species, and the hitherto unreported bisnorlabdane derivative 14,15-bisnor-13-oxolabd-8(17),11( E )-dien-19-oic acid (4). In addition, the bark yielded the known compounds crypotrienolic acid, isocupressic acid and sugiol. Structural assignments were largely based on the spectral data, including those derived from 2D NMR COSY and HETCOR experiments.