Curcumin and Bisdimethyl Curcumin Isolated from Curcuma longa Inhibit the Growth of Actinobacillus actinomycetemcomitans and Antibiotic-resistant Bacteria

Objective:Actinobacillus actinomycetemcomitans and antibiotic-resistant bacteria infection is the one of important problems in dental and medical fields. Therefore, new agents are needed to treat Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) and methicillin-resistant Staphylococcus aureus (MRSA) from oral infection. In the present study, we investigated the antimicrobial activity of Curcuma longa (C. longa) and the antibacterial components, curcumin and bisdimethyl curcumin, from C. longa has been isolated and identified by MS, ¹H-NMR, and ¹³C-NMR. Methods:C. longa was extracted with 80% MeOH, the extract was concentrated in vacua and the residue partitioned between H₂O and CHCl₃, EtOAc, and n-BuOH, respectively. The fractions of CHCl₃ were assayed for growth inhibitory activity against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA. Column chromatography of the most active fraction on silica gel, Sephadex LH20, and prep-HPLC gave purified compounds. The structure of compounds was identified by MS, ¹H-NMR, and ¹³C-NMR. Results:The CHCl₃ fraction from solvent partition possessed greater antibacterial potential than other fractions. The fraction was separated by prep-HPLC to purified compounds. The compounds were identified as bisdimethyl curcumin and curcumin by MS, ¹H-NMR, and ¹³C-NMR. The MICs of the fraction obtained from bisdimethyl curcumin and curcumim by column chromatography with silica gel and Sephadex LH20 A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384 ranged from 0.25 to 0.125 µ·/µ¢. The MICs of  bisdimethyl curcumin and curcumim against MRSA were 0.125 µ·/µ¢. Conclusion:These results suggest that curcumin and bisdimethyl curcumin isolated from C. longa by bioactivity-guided fractionation may have antibacterial activity against A. actinomycetemcomitans ATCC strains 43717, 43718 and 33384, and MRSA. This paper was supported by a grant No. R01-2001-000-00133-0 from Korean Science & Engineering Foundation.