HMOX1 and hepatitis B virus infection: Therefore, the induction of HO-1 might be a novel therapeutic option for inflammatory flares of hepatitis B. In this study, 3,4-O-dicaffeoylquinic acid significantly increased the expression of HO-1 in vitro and in vivo, thereby suggesting that the hepatoprotective and anti-HBV effects of 3,4-O-dicaffeoylquinic acid were achieved by HO-1 induction.