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Figure 4: Multivariate statistical analysis based on 1H NMR spectra of HepG2 cells. PCA scores plots obtained from aqueous (a, c, and e) and lipophilic extracts (b, d, and f) of HepG2 cells following exposure to matrine for 12, 24, and 48 h, respectively. Representative S-plots of the OPLS-DA model derived from 1H-NMR data for aqueous (g) and lipophilic (h) extracts of HepG2 cells after the exposure to high dose matrine for 48 h. (●) control group, (▲) low dose group, (■) middle dose group, and (★) high dose group. Ala: alanine, Cho: choline, GSH: glutathione, Lac: lactate, pCho: phosphocholine, Tau: taurine, Chol: cholesterol, FA: fatty acid, and UFA: unsaturated fatty acid.