Effect of epigallocatechin-3-gallate in green tea on malodor : a clinical study

The purpose of this study was to investigate the effect of epigallocatechin-3-gallate from green tea on oral volatile sulphur compounds (VSCs) in malodor. Thirty periodontitis subjects with baseline VSCs > 125 ppb were randomly assigned to use the test mouthrinse (50 mg/100 ml EGCG in distilled water) and control agent (distilled water) for 2 min in the double-blinded crossover study with at least 1 week washout period. Levels of hydrogen sulphide, methyl mercaptan and dimethyl sulphide in both test and control groups were measured by semiconductor simplified gas chromatography (Oral Chroma®) at baseline and 15, 30, 60 and 120 min after mouth rinsing. The gas changes were compared between the control and EGCG mouthrinse using Student’s t-test or Wilcoxon signed rank test. The results demonstrated that EGCG had significantly superior ability in gas reduction for methyl mercaptan than the control after mouth rinsing at 30, 60 and 120 min (P<0.05), while showed no significant gas reduction for hydrogen sulphide and dimethyl sulphide (P>0.05). This study concluded that EGCG had beneficial effect in reducing methyl mercaptan, which is the major component of VSC in periodontitis patient. It may be due to the antimicrobial activity of EGCG upon periodontal pathogens which are the prominent methyl mercaptan producers in oral cavity.