title: Rhodomyrtone: a new candidate as natural antibacterial drug from Rhodomyrtus tomentosa.
abstract: Rhodomyrtone [6,8-dihydroxy-2,2,4,4-tetramethyl-7-(3-methyl-1-oxobutyl)-9-(2-methylpropyl)-4,9-dihydro-1H-xanthene-1,3(2H)-di-one] from Rhodomyrtus tomentosa (Aiton) Hassk. displayed significant antibacterial activities against gram-positive bacteria including Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Staphylococcus epidermidis, Streptococcus gordonii, Streptococcus mutans, Streptococcus pneumoniae, Streptococcus pyogenes, and Streptococcus salivarius. Especially noteworthy was the activity against MRSA with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) ranging from 0.39 to 0.78 microg/ml. As shown for S. pyogenes, no surviving cells were detected within 5 and 6h after treatment with the compound at 8MBC and 4MBC concentrations, respectively. Rhodomyrtone displays no bacteriolytic activity, as determined by measurement of the optical density at 620 nm. A rhodomyrtone killing test with S. mutans using phase contrast microscopy showed that this compound caused a few morphological changes as the treated cells were slightly changed in color and bigger than the control when they were killed. Taken together, the results support the view that rhodomyrtone has a strong bactericidal activity on gram-positive bacteria, including major pathogens.
authors.affiliation: Department of Pharmaceutical Biology, University of Groningen, Antonius Deusinglaan 1, NL-9713 AV Groningen, The Netherlands.
authors.forename: Surasak
authors.initials: S
authors.lastname: Limsuwan
authors.forename: Erik N
authors.initials: EN
authors.lastname: Trip
authors.forename: Thijs R H M
authors.initials: TR
authors.lastname: Kouwen
authors.forename: Sjouke
authors.initials: S
authors.lastname: Piersma
authors.forename: Asadhawut
authors.initials: A
authors.lastname: Hiranrat
authors.forename: Wilawan
authors.initials: W
authors.lastname: Mahabusarakam
authors.forename: Supayang P
authors.initials: SP
authors.lastname: Voravuthikunchai
authors.forename: Jan Maarten
authors.initials: JM
authors.lastname: van Dijl
authors.forename: Oliver
authors.initials: O
authors.lastname: Kayser
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D006094:Gram-Positive Bacteria / Q000145:classification / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D027822:Myrtaceae / Q000737:chemistry*; D044004:Xanthones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D044004:Xanthones; C541823:rhodomyrtone