Chemopreventive Effects of Scordinin on Diethylnitrosamine and Phenobarbital‐induced Hepatocarcinogenesis in Male F344 Rats

Modifying effects of scordinin, a biological active component in garlic, on diethylnitrosamine (DEN)‐ and phenobarbital (PB)‐induced hepatocarcinogenesis were examined in rats. Male F344 rats, 5 weeks old, were divided into 8 groups. After a week, groups 1‐5 were given DEN (100 mg/ kg body weight, i.p.) once a week for 3 weeks, whereas groups 6‐8 received vehicle treatment. Group 2 was given 600 ppm scordinin‐containing diet in the initiation phase. From 4 weeks after the start of experiment, groups 3 and 5 were fed scordinin, and groups 1‐3 and 7 received drinking water containing 500 ppm PB. Group 6 was given scordinin diet alone throughout the experiment (24 weeks). The incidences of hepatocellular adenoma and carcinoma were significantly smaller in group 3 than those in group 1 (P<0.005 and P<0.05, respectively). The average numbers of liver neoplasms in groups 2 and 3 were significantly smaller than in group 1 (P<0.01 and P<0.0001, respectively). Glutathione S‐transferase placental form‐positive foci were also significantly decreased by scordinin treatment in the initiation or promotion phase. Scordinin significantly decreased the mean number of nucleolar organizer regions’ protein (AgNORs)/nucleus in hepatocellular adenoma and carcinoma. AgNORs/nucleus in the non‐lesional area was also significantly decreased by scordinin treatment during the promotion phase. These results suggest that scordinin is a promising chemopreventive agent for liver neoplasia.