Plants from Ulleung island ameliorate lipid accumulation and oxidative stress in oleic acid-induced in HepG2 Cells

Abstract

Oxidative stress can directly damage lipids, proteins, and DNA, which promotes the progression from steatosis to nonalcoholic fatty liver disease. This study aimed to determine the antioxidative effects of Campanula takesimana Nakai, Ilex integra THUNB., Indigofera pseudotinctoria Matsum., Rubus takesimensis Nakai, and Tsuga sieboldii from Ulleung Island and their ability to inhibit lipid accumulation in HepG2 cells. The total phenolics (TPC) and flavonoid (TFC) contents of extracts of the five plants were determined, and their antioxidative activities were analyzed using DPPH and ABTS radical scavenging ability, Fe 2+ reducing capacity (FRAP), oxygen radical absorbance capacity (ORAC), and thiobarbituric acid assays. Lipid accumulation was evaluated by Oil Red O staining and intracellular triglyceride (TG) assays. Rubus takesimensis Nakai had the highest TPC among the five plants. The antioxidant activity of R. Nakai was DPPH (IC 50 =0.30 mg/mL), ABTS (IC 50 =0.33 mg/mL), FRAP (318.61 μmol FeSO 4 /g), and ORAC (1.74 μmol TE/g). The lipid peroxidation inhibitory effect of R. Nakai was reduced to 52.51% at 1 mg/mL. Incubating HepG2 cells with extracts of the five plants reduced lipid and TG accumulation by >50%, and inhibited lipid peroxidation by ~19%. These results provided evidence for the development of functional foods based on these five plants from Ulleung Island, due to their antioxidant activities and ability to reduce lipid accumulation.