Xanthone with Antibacterial Activity against Actinobacillus actinomycetemcomitans

"Objective:" A. actinomycetemcomitans & MRSA have been emerging worldwide as one of the most important problems in dental fields. Therefore, new agents are needed to treat the A. actinomycetemcomitans and methicillin-resistant Staphylococcus aureus (MRSA). To investigate the antibacterial agents against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA from oral infection, several natural product extracts were screened. The methanol extract of Hypericum ascyron (H. ascyron) was found to have inhibitory activity against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA. "Methods:" H. ascyron was extracted with MeOH. The extract was suspended in H₂O and partitioned with CHCl₃, EtOAC, and n-BuOH in sequence. The CHCl₃ fraction showed remarkable antibacterial activity against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA. The antibacterial activity compound against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA by MIC was isolated successively through the screening system and various chromatography methods. "Results:" From this active chloroform subfraction, isolation and identification finally gave 1,3,6,7-tetrahydroxy-8-(3-methylbut-2-enyl)-xanthone by spectroscopic methods (MS, ¹H-NMR and ¹³C-NMR) as an active principle. The minimum inhibitory concentrations(MICs) of xanthone to the A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384 were 0.031 mg/ml. Among xanthone showed significant antibacterial activity against MRSA (0.125 mg/ml). "Conclusion:" These results suggest that 1,3,6,7-tetrahydroxy-8-(3-methylbut-2-enyl)-xanthone might have the antibacterial activity against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384 from periodontal infection and MRSA from acute oral infection. This paper was supported by a grant No. R01-2001-000-00133-0 from Korean Science & Engineering Foundation.