Abstract
The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic bacteria. Numerous studies have validated the traditional use of medicinal plants by investigating the biological activity of essential oils. The Eugenia caryophyllata (clove) essential oil was tested in vitro against a large number of oral pathogens (114 streptococci and 46 yeast strains) using a disc diffusion method. The cytotoxicity assay of Eugenia caryophyllata essential oil on cancer cells (HT29, A549, Hep2, raw 264.7) and normal cells (MRC-5) was determined by the ability of the cells to metabolically reduce MTT to a formazan dye. Our results revealed that Eugenia essential oil possessed an excellent antibacterial activity against oral streptococci including the cariogenic bacteria as well as an excellent antifungal activity. Furthermore, the Eugenia caryophyllata essential oil showed significant cytotoxic effects against all studied cancer cell lines as judged by IC50 and its value ranges from 15.75 to 200 mu g/ml. In conclusion, it is clear that clove oil shows powerful antibacterial and antifungal activity. The cytotoxic activity of the essential oil was dependent on the tested cell lines.