Orthogonal test design for optimization of the extraction of essential oil from Asarum heterotropoides var. Mandshuricum and evaluation of its antibacterial activity against periodontal pathogens.

The optimum extraction conditions of essential oil from Asarum heterotropoides var. Mandshuricum applied by an orthogonal L9(33) test were a water-to-raw material ratio of 17, a particle size of D 95 ≤ 3.8 mm and an extraction time of 2 h. In ingredient analysis, gas chromatography/mass spectrometry analysis identified the main components of essential oil as methyl eugenol (45.95%), safrole (17.48%) and 3,5-dimethoxytoluene (10.30%) orderly. In vitro, the minimum inhibitory concentration and minimum bactericidal concentration of essential oil were 0.01 and 0.02% against F. nucleatum, 0.04 and 0.08% against P. intermedia, and 0.005 and 0.005% against P. gingivalis. In vivo, administration of essential oil significantly suppressed alveolar bone resorption induced by F. nucleatum, with bone levels remaining comparable to non-infected mice. These results of antibacterial activity of essential oil in vitro and in vivo show the inhibition of periodontal pathogens and therapy of alveolar bone resorption in mice, suggesting that its essential oil could be a potential natural therapeutic agent for treatment of periodontitis in human beings.