Abies nephrolepis leaf phenolics prevent the inhibition of gap junction intercellular communication by hydrogen peroxide in rat liver epithelial cells

摘要

Recent reports suggest that carcinogenicity of hydrogen peroxide (H_{2}O_{2}) is implicated in inhibition of gap junction intercellular communication (GJIC), which is a cellular event associated with the tumor promotion. The present study investigated the effect of phenolics (KF) from leaves of Abies nephrolepis (Khingan fir) on inhibition of GJIC by H_{2}O_{2} in WB-F344 rat liver epithelial cells. The phenolics were extracted from fresh leaves by using 80% aqueous methanol, and were analyzed mainly as catechin derivatives including epigallocatechin gallate (EGCG) and catechin itself. KF and EGCG protected the inhibition of GJIC by H_{2}O_{2}, whereas butylated hydroxytoluene, a commercial antioxidant, had no effect. Our results indicate that KF exhibits potential chemopreventive effects against carcinogenesis, which may be attributable to phenolics such as EGCG.