In contrast, no growth inhibition zone was observed for early colonizing streptococci (S. mitis, S. sanguinis, S. oralis, and S. gordonii), Lactobacillus or Escherichia. These bacterial strains appeared to be resistant to the antibacterial activity of catechins, this would imply that catechins may be useful for the control of dental plaque accumulation, since it was formed efficient against Actinimyces and Fusobacterium (plaque-causing bacteria) selleckchem [31], [33] and [34]. Antimicrobial effects of catechins were also observed against Staphylococcus strains (including MRSA, which cause suppuration-related inflammation and bedsores [74]) and Candida (which causes oral candidiasis [75]) suggesting that catechins

may aid in the prevention of oral candidiasis and suppuration as well. Moreover, it has ABT-888 clinical trial been suggested that the ability of catechins to inhibit the growth of Staphylococcus, C. albicans, and

periodontopathic bacteria may help to suppress aspiration pneumonia [29] and [76]. Unlike the commercial gels, catechin gel did not show antimicrobial activity against early colonizing oral streptococci such as S. sanguinis, S. oralis, S. gordonii and S. mitis streptococci which are part of the normal oral microbial flora and help maintain healthy oral cavity by preventing the adhesion and proliferation of some pathogenic microorganism [32]. Early colonizing streptococci have been associated with low numbers of periodontopathic bacteria and the absence of periodontal disease [77]. It is very important to keep the thin layer of bacterial accumulation formed during the early stage of dental plaque since it possess low pathogenicity. Therefore, it is necessary to not only suppress the oral pathogenic microorganisms that cause disease but Dehydratase also to protect the oral flora that play an important

role in innate immunity and catechin gel can efficiently do so. A comparison between catechin gel and catechin solution mixed solution is show in Fig. 2[78]. The quantity of residual catechin was measured by spectrophotometer [73]. Most of the catechins in solution were removed after first washing, whereas more than 90% of the catechins in catechin gel remained after five rounds of washing (Fig. 2a). The difference in residual catechins between the catechin gel and the solution was significant (p < 0.01). The inhibition zones for S. mutans were similar between washed and non-washed catechin gel ( Fig. 2b). In contrast, the catechin solution produced no growth inhibition after the first wash. Same results were observed against A. naeslundii and S. aureus. Furthermore, incubation of S. mutans either with catechin gel or solution showed that the antimicrobial activity of the catechin gel was higher than that of catechin solution and was nearly equivalent to that of freshly prepared one ( Fig. 2c). This further supports the possible clinical applications of catechin gel.