Inhibitory effect of Aloe arborescens Miller var. natalensis Berger (Kidachi aloe) on induction of preneoplastic focal lesions in the rat liver

Inhibitory effects of freeze‐dried Aloe arborescens Miller var. natalensis Berger (Kidachi aloe) whole leaf powder (Aloe) on induction of preneoplastic glutathione S‐transferase (GST‐P) positive hepatocyte foci GST‐P⁺ were studied in male rats. Experiment 1: Group 1 was fed a diet containing 30% Aloe for 8 days. At day 7, the carcinogen, 2‐amino‐3‐methylimidazo(4,5‐f)quinoline(1Q, 100 mg/kg, i.g., one dose), was given 12 h after partial hepatectomy (PH) for initiation, followed by phenobarbital (PB) and D‐galactosamine for promotion and then killed at week 11. Experiment 2: Group 1 was given diethylnitrosamine (DEN, 200 mg/kg, i.p.) for initiation then a diet containing 30, 20 or 10% Aloe during weeks 3–8, with PH at week 3. In both experiments, groups 2 and 3 were treated as in group 1 without Aloe or carcinogens. GST‐P⁺ in group 1 lesions larger than 5 cells in experiment 1 and 200 μm in diameter in experiment 2 were compared with group 2. In experiment 1, the number of cells in group 1 showed a tendency for decrease. In experiment 2, the areas in group 1 were significantly decreased. The results indicate that 30% Aloe exerts inhibition of the promotion, and possibly of the initiation stage of hepatocarcinogenesis.