Inhibitory effects of macrocarpals on the biological activity of Porphyromonas gingivalis and other periodontopathic bacteria.
OBJECTIVE
Macrocarpals, which are phloroglucinol derivatives contained in eucalyptus leaves, exhibit antimicrobial activity against a variety of bacteria including oral bacteria. This study examined effects of macrocarpals A, B, and C on periodontopathic bacteria, especially Porphyromonas gingivalis.


METHODS
Macrocarpals A, B, and C were purified from a 60% ethanol-extract of Eucalyptus globules leaves. To investigate antibacterial activity, representative periodontopathic bacteria were cultured in media with or without various amounts of macrocarpals; subsequently, the optical density at 660 nm was measured. Macrocarpal inhibition of P. gingivalis Arg- and Lys-specific proteinases was assessed by spectrofluorophotometric assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The effect of macrocarpals on P. gingivalis binding to saliva-coated hydroxyapatite beads was examined with (3)H-labeled P. gingivalis.


RESULTS
Growth of P. gingivalis was inhibited more strongly than growth of Prevotella intermedia or Prevotella nigrescens and Treponema denticola by macrocarpals, however, Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum were much more resistant. Macrocarpals inhibited P. gingivalis Arg- and Lys-specific proteinases in a dose-dependent manner. The enzyme-inhibitory effect of macrocarpals was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis in which hemoglobin degradation by P. gingivalis proteinase was inhibited by macrocarpals. P. gingivalis binding to saliva-coated hydroxyapatite beads was also strongly attenuated by macrocarpals.


CONCLUSIONS
Macrocarpals A, B and C demonstrated antibacterial activity against periodontopathic bacteria. Among tested bacteria, P. gingivalis displayed the greatest sensitivity to macrocarpals; additionally, its trypsin-like proteinase activity and binding to saliva-coated hydroxyapatite beads were inhibited by macrocarpals. These results indicate that eucalyptus leaf extracts may be useful as a potent preventative of periodontal disease.
Nagata
H
H
Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan. nagatah@dent.osaka-u.ac.jp
Inagaki
Y
Y
Yamamoto
Y
Y
Maeda
K
K
Kataoka
K
K
Osawa
K
K
Shizukuishi
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001426:Bacterial Proteins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D005052:Eucalyptus; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000201:enzymology / Q000472:pathogenicity; D011480:Protease Inhibitors / Q000494:pharmacology*; D012717:Sesquiterpenes / Q000494:pharmacology; D014774:Virulence / Q000187:drug effects
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010936:Plant Extracts; D011480:Protease Inhibitors; D012717:Sesquiterpenes; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; C091975:prtR protein, Porphyromonas gingivalis W50; C044574:lysine-C peptidase