Therefore, EPS and acidification of the biofilm matrix
are critical for the formation and establishment of dental caries and
offer primary targets for chemotherapeutic intervention.
In view of the high detrimental effects of S. mutans biofilms,
along with the side effects associated with the presently available
therapeutic agent chlorhexidine (CHX), there have been significant
efforts to find new agents to control and decrease S. mutans
pathogenicity [6]. Although the antimicrobial agent CHX has been
used in dentistry, it is reported to have toxic effects, such as
inducing an inflammatory reaction and tissue necrosis associated
with the inflammatory response [7]. There is some evidence that
many natural molecules are good antibacterial agents showing
activity against a number of oral pathogens [8]. There have also
been a considerable number of reports describing the antibacterial
effect of a group of plant-derived compounds, but few of them have
discussed the molecular basis of their activity [9]. Eugenol (4-allyl-
2-methoxyphenol) is a major component of the essential oil
expressed from the buds of cloves (Syzygium aromaticum) and is
known as a safe natural product. Apart from being used as a
flavouring agent for foods and a component in curative dentistry
[10], it is also reported to have in vitro activity against fungal
biofilms [11].