Objective: To investigate the inhibitory mechanisms of ginsenoside F1 on hydrogen peroxide induced cholesterol metabolism disorder and oxidative stress in HepG2 cells.
Methods: 1, 1-diphenyl-2-picrylhydrazyl(DPPH) and oxygen radical absorbance capacity(ORAC) tests were used to detect the scavenging effect of ginsenoside F1 on nitrogen and oxygen free radicals. HepG2 cells were treated with 400 μmol/L hydrogen peroxide and pretreated with 10, 20 and 40 μmol/L ginsenoside F1. Mitochondrial membrane potential(MMP) and total cholesterol levels were detected by JC-1 method and cholesterol kit, respectively. The protein expression levels of sterol-regulatory element binding proteins(SREBP2)and 3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR) in cholesterol synthesis pathway were detected by Western blot.
Results: The DPPH clearance rate of ginsenoside F1 was much lower than that of 6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid(Trolox), but the ORAC capability of ginsenoside F1 was stronger, which was comparable to Trolox. The MMP and protein expression of SREBP2 were significantly decreased in injured group(P<0.05). The cholesterol and protein expression of HMGCR were significantly increased(P<0.05). Whereas, compared with the injured group, the MMP and protein expression of SREBP2 were significantly increased after 10, 20 and 40 μmol/L ginsenoside F1 pretreatment of injured cells(P<0.05). The cholesterol level and protein expression of HMGCR were significantly lower than injured group with concentration-dependent decreases(P<0.05).
Conclusion: Ginsenoside F1 can protect against hydrogen peroxide induced oxidative stress in HepG2 cells by inhibiting oxygen free radicals and protecting mitochondria. And its mechanism may be related to the intervention of SREBP2/HMGCR pathway in regulating cellular cholesterol anabolism.
Keywords: 3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR); cholesterol; ginsenoside F1; oxidative damage; sterol-regulatory element binding proteins(SREBP2).