Fig. 4. OPLS score plot of the experimental groups. Box (green), NDM group; circle (blue), NC group; triangle (red), DM group. (A) ESI+, NDM group vs. NC group, R2X(cum) = 0.205, R2Y(cum) = 0.461, Q2(cum) = 0.14; DM group vs. NC group, R2X(cum) = 0.245, R2Y(cum) = 0.448, Q2(cum) = 0.0629. (B) ESI−, NDM group vs. NC group, R2X(cum) = 0.403, R2Y(cum) = 0.399, Q2(cum) = −0.0344; DM group vs. NC group, R2X(cum) = 0.349, R2Y(cum) = 0.513, Q2(cum) = 0.223. Heat map for identified lipids in experimental groups (C). The colour of each section is proportional to the significance of lipid change (red, up-regulated; green, down-regulated). Rows: samples; columns: metabolites.