Fig. 3. The nontoxic effects of chlorogenic acid and amino acid ester-coupled caffeoylquinic acids derivatives on cell viability. (A) Cells treated with 10 μmol L⁻¹ compounds 5a–5f and 6a–6f for 24 h respectively. (B) The regulation effects of chlorogenic acid and amino acid ester-coupled caffeoylquinic acids derivatives on oleic acid-elicited lipid accumulation in HepG2 liver cells. HepG2 cells were co-incubated in serum-free DMEM containing 100 μmol L⁻¹ oleic acid (OA) (Model) and co-treated with 10 μmol L⁻¹ of simvastatin (S or Sim) or chlorogenic acid (CA), compounds 5a–5f and 6a–6f for 24 h respectively. (C) Oil red O staining images. The data are expressed as the mean ± SD (n = 8) from three independent experiments. ^####p < 0.0001 versus control group (Ctrl); ****p < 0.0001 versus OA-treated cells.