Antibacterial Activity of Selected Essential oils against Streptococcus sobrinus and Porphyromonas gingivalis
Plant essential oils have been used medicinally in history. The antibacterial screening of selected plant essential oils against Porphyromonas gingivalis and Streptococcus sobrinus was evaluated by MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) assay. Among them, thujopsis dolabrata (Asunaro) essential oil was selected as a fairly effective sample against P. gingivalis (MIC=1 mg/ml) and S. sobrinus (MIC=1 mg/ml) respectively. Moreover, Callitrisintratropica (Australian blue cypress; cypress) was also screened as a fairly effective sample only against S. sobrinus (MIC=0.5 mg/ml). Furthermore, five effective compounds, (+)-cuparene, (-)-thujopsene, (+)-cuparenol, (-)-guaiol and a novel sesquiterpenoid were isolated by a performance of a series of chromatography, and identified by nuclear magnetic resonance (NMR) and matrix assisted laser desorption/ionizationtime of flight mass spectrometry (MALDI-TOFMS). Among them, (+)-cuparenol was the most effective compound with a MIC of 0.125 mg/ml against P. gingivais. Additionally, the novel sesquiterpenoid (MIC=0.25 mg/ml) was identified as the first time isolation from C. intratropica.