Isolation and characterization of macrocarpals B--G antibacterial compounds from Eucalyptus macrocarpa.

Six novel phloroglucinol dialdehyde diterpene derivatives (macrocarpals B--G), which have antibacterial activity, were isolated from leaves of Eucalyptus macrocarpa. These compounds have closely related structures, the molecular formula for B--F being C28H40O6, and that of G being C28H38O5. The structures of macrocarpals B, D, and G were analyzed by means of NMR analyses.