Further antibacterial diterpenes from the bark and leaves of Juniperus procera Hochst ex Endl

The bark of Juniperus procera yielded three antibacterial diterpenoids, (+)-E-communic acid (1), (+)Z-communic acid (2) and (+)-totarol (3). Compound 2 exhibited significant activity against Gram-positive bacteria, while 1 was found to be less active. Compound 3, on the other hand, demonstrated potent activity against Mycobacterium organisms, while its corresponding 3 beta-hydroxy-derivative 4 was found to be inactive. The chromatographic separation of(+)-Z-communic acid (2) from (+)-E-communic acid (1) and those previously unreported spectral data of 1 and 2 are described. In addition, the leaves yielded (+)-8 alpha-acetoxyelemol, beta-peltatin A methyl ether and deoxypodophyllotoxin.