Invitro Inhibitory Activitiesofforty-Eight Plantessential Oils Against Dental Cariesandperiodontal Disease

Dental caries and periodontal disease are the most two oral diseases worldwide, both of them are bacteria-induced diseases. Dental caries, also called tooth decay, its formation is correlated to bad oral cleaning manners, the accumulation of numerous saccharides and the breeding of oral bacteria, especially Streptococcus sobrinus. AndS. sobrinuscan produce amount of glucosyltransferase (GTF), the GTFswould convert sucrose into sticky glucan which can provide the sites for the adhension of other oral bacteria and plays a important role in the formation of dental plaque;at the same time, they will also produce some acid substance, such like lactic acid, the acid will change the PH of the tooth surface and cause the tooth demineralization, resulting in tooth caries. Howerver, periodontal disease is the most critical factor that cause tooth loss, it has two stages:gingivitis and periodontitis. Moreover, periodontal disease is caused by some oral bacteria, especially Porphyromonas gingivalis. When the bacteria were accumulated to a certain extent, they will produce a lot of matrix metalloproteinases (MMPs) which can decompose collagens, the main component of extracellular matrix, and cause gingivitis, if the patients can not get timely and proper treatments, it will furtherly develop into periodontitis.In this study, the inhibitory activities of 48 selected plant essential oils againstS. sobrinus,P. gingivalisand two key enzymes (GTF and MMP-9) were performed, the results was showed below:1. Inhibitory activities of selected essential oils against GTF and MMP-9In this part, there are 48 plamt essential oils were used in the study of inhibitory activities against GTF. The results showed that there were 12 essential oils have the inhibitory ratio below 20%:Callitris glaucophylla.Matricaria recutita, Boswellia serrata, Zingiber officinale, Pinus parviflora, Abies firma, Commiphora molmol, Pogostemon cabin, Rosemarinus officinalis, Cryptomeria japonica(branch part), Cryptomeria japonica(leaf part), Vetiveria zizanioidesessestial oils; among them, only Pogostemon cabinessential oil (40.8%)and Vetiveria zizanioidesessestial oil (44.0%) have the inhibitory ratio over 40%, thus we can say the results are not so valuble. However, according to the above GTF results,10 essential oil samples which have relatively good inhibitory activity were used in the study of inhibitory activitis against MMP-9. The results showed that only Commiphora molmolessential oil have inhibitory activity against MMP-9, the inhibitory ratiao is 37,5; neverthless, the other 9 essential oils show no inhibitory activities against MMP-9, thus we can say the results are not so valuble.2. Antibacterial activities of selected essential oils against S. sobrinusand P. gingivalisIn this part, the antibacterial activities of selected essential oils against two oral pathogens:S. sobrinusand P. gingivaliswere performed. Among all the essential oils, Thujopsis dolabrataand Callitris intratropicaessential oils are the most two effective samples againstS. sobrinus, the minimum inhibitory concentration (MIC) werelmg/ml and 0.5mg/ml respectively and the minimum bactericidal concentration (MBC) were 1mg/ml and 2mg/ml respectively. Besides, T. dolabrataessential oil was also the most effective sample against P. gingivalis, the MIC and MBC were 1mg/ml and 4mg/ml. So T. dolabrataand C. intratropicaessential oils were selected for the further isolation and purification of effective compound against the two bacteria.3. Isolation and purification of effective compoundsIn this part, open silica gel column chromatography and preparative high performance liquid chromatography were used in the isolation and purification of effective compound agasint S. sobrinusand P. gingivalis. And five effective compounds were obtained: (-)-thujopsene, (+)-cuparene, (+)-cuparenol, (-)-guiaol and a novel sesquiterpenoid. Among them, (-)-thujopsene, (+)-cuparene and (+)-cuparenol were isolated from T. dolabrataessential oil, however, (-)-guiaol and a novel sesquiterpenoid were isolated from C. intratropicaessential oil. Moreover, (-)-thujopsene and (+)-cuparene were effective agasint P. gingivalis, the MIC were 0.5mg/ml and 4 mg/ml respectively; while (+)-cuparenol, (-)-guiaol and a novel sesquiterpenoid were effective againstS. sobrinus, the MIC were 0.125mg/ml,0.25 mg/ml and 0.5 mg/ml respectively.