Cystein protease reduces tongue coating and volatile sulfur compounds

Objectives: It is well known that a tongue coating is one of the major sources of oral malodor. Therefore, the purpose of this study was to determine whether the tablets containing actinidin which was a cysteine protease extracted from Kiwifruit would effect on the levels of bacteria on tongue coating and reduction of volatile sulfur compounds (VSCs) concentration in mouth air. Methods: We enrolled5 males aged 34-54 years. Subjects took two tablets (1.0g) that contained 3% actinidin. Their tongue coating status such as prevalence of periodontopathic bacteria and amount of tongue coating were assessed before and after taking tablets in addition to the levels of VSCs in oral cavity. Real-time PCR was used to determine levels of total bacteria and periodontopathic bacteria, including Prevotella intermedia, Porphyromonas gingivalis, Bacteroides forsythus, Treponema denticola and Fusobacterium nucleatum, in samples that were obtained from tongue dorsum. Area ratios of tongue coating per whole area of dorsumwere visually evaluated by the image analysis. VSC concentration was measured by gas chromatography (GC) equipped with a flame photometric detector. Wilcoxon's test was employed to compare two means. Results: As a result of taking cysteine protease, mean of total bacterial counts declined from 7.32 x 107 to 3.17 x 107 (p=0.091). The ratios of each periodontopathic bacteria count, except for F. nucleatum, per total bacterial counts tended to increase, while counts of P. gingivalis, B. forsythus and F. nucleatum tended to decline. Mean area ratios of tongue coating reduced from 70.7% to 47.6% (p=0.08). Each concentration of H2S, CH3SH and (CH3)2S decreased after taking cysteine protease and showed value below detectable limit by GC. Conclusions: Our study results might suggest that the tablets containing cysteine protease could reduce both amount of bacterial in oral cavity and oral malodor.