Gallomyrtucommulones G and H, New Phloroglucinol Glycosides, from Bioactive Fractions of against Species.

Myrtaceae family is a continuous source of antimicrobial agents. In the search for novel antimicrobial agents against species, bioactive fractions of L., growing in the Sardinia island (Italy) have been investigated. Their phytochemical analysis led us to isolate and characterize four alkylphloroglucinol glycosides (-), three of them gallomyrtucommulones G-H (,), and myrtucommulonoside () isolated and characterized for the first time. The structures of the new and known compounds, endopreroxide G3 (), myricetin-3--glycosides (,) were determined based on the spectroscopic evidence including 1D-/2D-NMR and HR-MS spectrometry. Enriched fractions as well as pure compounds were tested for their antimicrobial activity by broth micro-dilution assay against and Results reported herein demonstrated that gallomyrtucommulone G () showed a selective antimicrobial activity against both strains (ATCC 29213 and 43300) until 16 μg/mL while gallomyrtucommulone D () showed the best growth inhibition value at 64 μg/mL.