In addition, 6-shogaol inhibited ROS production in a human polymorphonuclear neutrophils (PMNs) [36] and increased HO-1 expression in human hepatoma cell line (HepG2) [37], and 6-shogaol-rich extract from ginger also up-regulated the expression levels of HO-1 and Nrf2 via the p38 mitogen-activated protein kinase (MAPK) pathway in HepG2 cells [38]. Here, HMOX1 is linked to hepatocellular carcinoma.