Fig. 2

Orthogonal partial least square-discriminate analysis (OPLS-DA) score charts and cross-validation test in the positive and negative ion mode (A-D). A, C OPLS-DA score graph and mode cross-validation graph for the CEG and N groups in the positive ion mode. B, D OPLS-DA score graph and mode cross-validation graph for the CEG and N groups in the negative ion mode. CEG = Green square and N = Dark blue dots. Volcano map based on fold change (FC) analysis and t test (E-F). E, F CEG and N volcano diagrams in the positive and negative ion modes. Up regulated metabolites = Red circle, Down regulated metabolites = Blue circle