To investigate the molecular mechanisms underlying the role of Ixeris dentataa
in the prevention of high glucose-induced lipid accumulation in human HepG-2 hepatocytes.
IDE extract was prepared by maceration in ethyl acetate. Its fractionation was carried out by
column chromatography. HepG-2 cells were pretreated with various concentration of IDE (0, 10, 20, 40
and 80 μg/mL) and then treated with serum-free medium with normal glucose (5 mM) for 1 h, followed
by exposure to high glucose (30 mM D-glucose) for 24 h. Cell viability and cytotoxicity parameters were
measured using lactate dehydrogenase (LDH) and MTT assay while triglyceride and total cholesterol
levels were evaluated using respective enzymatic reagent kits. Protein expressional levels were
analyzed by Western blotting.
IDE did not influence the cell viability (up to 200 μg/mL) and did not show any signs of
cytotoxicity (up to 80 μg/mlL. IDE significantly attenuated lipid accumulation in human HepG2
hepatocytes when exposed to high glucose (30 mM D-glucose) in a dose-dependent manner (p < 0.05,
0.01 and 0.001 at 20, 40 and 80 μg/mL concentrations, respectively). Nile red staining showed that 10,
20, 40 and 80 μg/mL concentrations of IDE reduced lipid accumulation by 23.4, 34.8 (p < 0.05), 46.5 (p
< 0.01) and 53.2 % (p < 0.001), respectively. The increased levels of triglycerides and total cholesterol
were also attenuated by IDE (p < 0.001 at 80 μg/mL). Further, IDE attenuated the expression of fatty
acid synthase and sterol regulatory element-binding protein-1. Adenosine monophosphate-activated
protein kinase was also activated by IDE treatment when exposed to high glucose level (30 mM Dglucose)
in human HepG2 hepatocytes.
The findings indicate that IDE exerts hypolipidemic effect by inhibiting lipid biosynthesis,
mediated via AMPK signaling. This probably explains the extract’s beneficial effect in various