Fig. 4

Differing expression trends of differential metabolites in each group (A) (B). PCA map showing metabolomics results in positive and negative ion modes (C) (D). Each point in the figure represents a sample. Different colors represent different groups. Furthermore, closer samples represent closer metabolite expression patterns, which means more minor differences between the groups. We used the PCA method to evaluate the aggregation degree and the overall distribution trend of samples within the group