Effect of phlorofucofuroeckol-A on the hepatoprotection in tacrine-induced HepG2 cells

Abstract

Brown sea plants are very popular seafood and many people ingest them as a healthy food in Korea, Japan, and China. The plants are known to contain several phlorotannins, which have been reported to have several biological activities, such as antioxidation, antimutaion, antiskinaging, and hepatoprotective activities. In previous study, we isolated several phlorotannins from the brown algae Ecklonia stolonifera through solvent fractionation and HPLC chromatographies. Among isolated phlorotannins from E. stolonifera, phlorofucofuroeckol-A (PFF-A) showed the highest antioxidant activity and the hepatoprotective activity against tacrine-induced in HepG2 cells. Our objective was to investigate the hepatoprotective effects of PFF-A on the tacrine-induced HepG2 cells and to assess the possible mechanism of the hepatoprotection by measuring the change of proteins responsible to the cell protection. HepG2 cells were cultured in minimal essential medium containing 10% fetal bovine serum. Cell damage was induced by treatment of 0.3 mM tacrine for 24 hr and cell protective effect was determined by the addition of different concentration of PFF-A. The expression level of proteins was determined with Western blot. Our result showed that the cytotoxic effects of tacrine to HepG2 cells were caused by ROS generation and induction of Fas, pJNK, cleaved caspase-3, and PARP, which are important proteins on apoptosis, with dose dependent pattern. Treatment of PFF-A showed the suppression of ROS generation and the expression of Fas/FasL-mediated apoptotic proteins with dose dependent manner. Furthermore, the Fas was regulated through inhibition of pJNK by SP600125, pJNK inhibitor. The hepatoprotective effects of PFF-A on tacrine-induced HepG2 cells appeared through reducing ROS generation and down-expression of Fas, Fas-L, pJNK, cleaved caspase-3 and PARP. These findings provide a biochemical basis for the use of PFF-A as a functional food component. Also marine brown plant such as E. stolonifera may have a potential for the utilization of functional food source for preventing hepatotoxicity.