Eurobusones A-D, four antibacterial formyl phloroglucinol meoterpenoids from Eucalyptus robusta.

Four antibacterial formyl phloroglucinol meroterpenoids (FPMs), eurobusones A-D (1–4), as well as six known analogues (5–10), were isolated from the leaves of Eucalyptus robusta. Their structures were determined by the analysis of spectroscopic data and electron circular dichroism (ECD) calculation, along with the application of Snatzke helicity rules. Among them, compounds 2 and 8 – 10 showed good activity against Staphylococcus aureus , Pseudomonas aeruginosa and Bacillus subtilis with MIC 50 values less than 1.00 μg/mL. [Display omitted] • Four formyl phloroglucinol meroterpenoids (1 – 4) were isolated from Eucalyptus robusta. • Their absolute configurations were determined by the electron circular dichroism calculation and the Snatzke helicity rules. • All isolates showed activity against Staphylococcus aureus , Pseudomonas aeruginosa and Bacillus subtilis. [ABSTRACT FROM AUTHOR]