Possible prevention by abieslactone of development of diethylnitrosamine-initiated GST-P positive foci in the rat liver

Triterpenoid compounds, isolated from plants of Abies genus (Pinceae), are known to exert anti‐tumor promotion activities in mouse skin carcinogenesis. In the present study, we investigated whether AVB‐1 and acid and acid methyl ester derivatives have inhibitory effects on rat hepatocarcinogenesis by using a liver medium‐term bioassay for carcinogens (Ito’s test), immunohistochemically assessing the numbers and areas per cm2 of preneoplastic lesions, glutathione S‐transferase placental form (GST‐P)‐positive foci. In experiment 1, 6‐week‐old male Fisher 344 rats were given a single intraperitoneal injection of diethylnitrosamine (200 mg/kg b.w.) and subjected to two‐thirds partial hepatectomy at week 3. From weeks 2 to 8, the compounds were given three times a week at a dose of 1 mg/kg b.w. by i.g. gavage and found to significantly decrease the number of GST‐P‐positive foci in the liver. In experiment 2, AVB‐1 was given three times a week at doses of 3, 1, or 0.3 mg/kg b.w. by i.g. gavage from weeks 2 to 8. All doses of AVB‐1 significantly decreased the numbers of GST‐P‐positive foci. Thus, our results suggest that AVB‐1 is a chemopreventive agent for rat hepatocarcinogenesis. Teratogenesis Carcinog. Mutagen. 21:223–229, 2001. © 2001 Wiley‐Liss, Inc.