Figure 2
Hierarchical clustering analysis of the oral metabolites obtained using the three sampling methods. The results of quantitative analysis represented by a hierarchical clustering heat map and box plots of z-scores. (a) Hierarchical clustering heat map (Pearson correlation distance, average-linkage method). Green box: cluster characteristic of stimulated saliva (SS) samples (Cluster 1); red box: cluster characteristic of all three sampling methods with similar metabolite profiles (Cluster 2); blue box: cluster characteristic of mouth-rinsed water (MW) samples (Cluster 3). (b–d) Box plots of average z-scores of all metabolites in each cluster. Z-score was obtained by normalization among the all samples. Each dot represents the z-score corresponding to each subject. (b) Cluster 1, (c) Cluster 2, (d) Cluster 3 (*p < 0.05, Steel–Dwass test).
