Antioxidant Activites And Indueed-hepatoma Apoptosis Properties Of Eriodictyol

Eriodictyol is a natural flavonoid compound that widely distributed in fruits andvegetables. Eriodictyol is a potential antioxidant.By far, research on eriodictyol antioxidantactivity, anti-cancer activity and mechanism is limited. Cancer is one of the most threateningdiseases in the21st century, however, cancer drugs have side effects and limitations.To findeffective antioxidant from natural products for the prevention and treatment of freeradical-related diseases and to find a safe and effective anti-tumor compounds.To furtherreveal antioxidant-prooxidant and cancer, this research investigated the antioxidant and anti-tumor properties of eriodictyol.In vitro radical scavenging activity of eriodictyol was evaluated based on DPPH,hydroxyl free radicals scavenging capacity. Protective effects of eriodictyol on freeradical-induced damages of protein, lipid, DNA were evaluated based on oxidation models ofBSA, rat liver tissue, plasmid DNA induced by AAPH.Moreover,we also evaluated the cytotoxicity of eriodictyol against hepatoma cells byMTT assay. Eriodictyol-induced apoptosis was investigated by AO/EB and DAPI stainingassay, and western blot analysis was used to examine the poly (ADP-ribose) polymerase(PARP) cleavage. The morphological change of the human hepatoma cell line (HepG2)treated by eriodictyol was observed on inverted mierocope.The possible pro-apoptosismechanism of eriodictyol was investigated in HepG2cellline, ROS generation wasinvestigated using the fluorescent dye H2-DCFDA, the mitochondria-specific lipophiliccationic fluorescence dye JC-1was used to assay the mitochondrial membrane potential (△Ψ), western blot analysis was used to examine apoptosis-related proteins Bcl-2and Baxexpression changes.The results of in vitro antioxidant showed that25-200μmol/L eriodictyol had strongscavenging activity against DPPH free radical and the median inhibitory concentrations (IC50values) of eriodictyol were95.7μmol/L. However, the scavenging activity on hydroxyl freeradical was weaker. The strong inhibitory effect against oxidative damage of protein, lipid,DNA induced by free radical presented a dose-dependent manner.The results of cells toxicity are listed as follows.①Eriodictyol significantly reduced the HepG2、Hep3B、HuH-7cells viability in a time-and dose-dependent manner. However, thecells toxicity on normal liver cells HL-7702、BRL-3A were weaker.Treatment with eriodictyolat400μmol/L for48h, the survival rate of the three kinds of liver cancer cells were22.36%,57.28%,43.85%respectively. However, HL-7702cells survival rate was no significant impact,the BRL-3A cell survival rate was68.67%.②Eriodictyol significantly induces the HepG2、Hep3B、HuH-7apoptosis in a time-and dose-dependent manner. However, the effects ofpro-apoptosis on normal liver cells HL-7702、 BRL-3A were weaker. Treatment witheriodictyol at400μmol/L for48h, the apoptosis rate of the three kinds of liver cancer cellswere90.44%、96.67%、76.23%respectively. However the apoptosis rate of the two kinds ofnormal liver cells were45.95%、41.22%.③In HepG2cells eriodictyol at1–100μmol/Linduced Bcl-2/Bax ratio decrease. Eriodictyol at100–400μmol/L significantly decreasedmitochondrial membrane potential (△Ψ).④Eriodictyol at100–400μmol/L significantlyincreased the intracellular ROS levels in HepG2cells.However, the pretreatment of a ROSinhibitor (N-Acetyl-L-cysteine, NAC) significantly inhibited the increased of ROS levels,attenuated the apoptosis and completely blocked mitochondrial membrane potential collapseinduced by eriodictyol.In conclusion:Eriodictyol has ability to scavenge DPPH free radical and inhibitmacromolecules damage induced by free radicals. Eriodictyol induces HepG2apoptosis in aROS-mediated mitochondria-dependent manner. Eriodictyol has the potential treatmentagainst liver cancer, but there are also slight impact on normal liver cells.