Autophagic cell death of human hepatoma G2 cells mediated by procyanidins from Castanea mollissima Bl. Shell-induced reactive oxygen species generation.

The autophagy of human hepatoma G2 (HepG2) cells induced by procyanidins from chestnut (Castanea mollissima Bl.) shell (CSPCs) was investigated, and the inherent relationship between autophagic levels and reactive oxygen species (ROS) generation was studied. The results showed that CSPCs induced HepG2 cell death in a time- and concentration-dependent manner, increased the accumulation of autophagolysosomes and microtubule-associated proteins light chain 3-II (LC3-II, a marker of autophagy). However, these phenomena were not observed in the group pretreated with the autophagy inhibitor 3-MA, suggesting that CSPCs induced HepG2 cell autophagy. Furthermore, we found that CSPCs triggered ROS generation in cells, while the levels of ROS decreased in the N-acetylcysteine (Nac) co-treatment, revealing that CSPCs-mediated autophagy was partly blocked by Nac. In addition, treatment with CSPCs decreased the mitochondrial membrane potential of HepG2 cells. These results suggested CSPCs could trigger autophagy via ROS generation, which may be associated with the mitochondria-dependent signaling way.