The nontoxic effects of chlorogenic acid and its derivatives on cell viability. (A) Cells treated with 10 μmol/L compounds 3a–3g, for 24 h, respectively, and (B) compounds 4a–g, for 24 h, respectively. The regulation effects of chlorogenic acid and its derivatives on oleic acid-elicited lipid accumulation in HepG2 liver cells. HepG2 cells were co-incubated in serum-free DMEM containing 100 μmol/L oleic acid (OA) (Model) and co-treated with 10 μmol/L of simvastatin (SimV) or chlorogenic acid (CA), (C) compounds 3a–g, for 24 h, respectively, and (D) compounds 4a–g, for 24 h, respectively. (E) Oil red O staining images. The data are expressed as the mean ± SEM (n = 8) from three independent experiments. ### p < 0.001 versus blank group (Blk); * p < 0.05 versus OA-treated cells; ** p < 0.01 versus OA-treated cells; *** p < 0.001 versus OA-treated cells.