Open AccessDecreased Levels of 2‐Amino‐3‐methylimidazo[4,5‐ f ]quinoline‐DNA Adducts in Rats Treated with β‐Carotene, α‐Tocopherol and Freeze‐dried Aloe
Author(s) -
Uehara Nobuaki,
Iwahori Yoshio,
Asamoto Makoto,
BabaToriyama Hiroyasu,
Iigo Masaaki,
Ochiai Masako,
Nagao Minako,
Nakayama Masafumi,
Degawa Masakuni,
Matsumoto Kazuyuki,
Hirono Iwao,
Beppu Hidehiko,
Fujita Keisuke,
Tsuda Hiroyuki
Publication year - 1996
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1996.tb00228.x
Subject(s) - cyp1a2 , chemistry , adduct , carcinogen , anticarcinogen , quinoline , carotene , tocopherol , biochemistry , enzyme , antioxidant , food science , biological activity , vitamin e , microsome , in vitro , organic chemistry
To assess mechanisms of chemoprevention of hepatocarcinogenesis by trans ‐β‐carotene (β‐C), DL‐α‐tocopherol (α‐T), and freeze‐dried whole leaves of Kidachi aloe (Aloe), formation of 2‐amino‐3‐methylimidazo[4,5‐ f ]quinoline (IQ)‐DNA adducts was measured by 32 P‐post‐labeling analysis, and CYP1A1 and CYP1A2 protein levels were analyzed by ELISA. Group 1 rats were fed diet containing 0.02%β‐C, 1.5%α‐T or 30% Aloe over an 8‐day period, while group 2 was given basal diet alone. On day 7, all animals were subjected to two‐thirds partial hepatectomy (PH). Twelve hours after PH, they received a single dose of the carcinogenic food pyrolysate IQ (100 mg/kg) intragastrically, to initiate hepatocarcinogenesis. Rats were killed 6, 12, 24 and 48 h after IQ administration. The levels of adducts, expressed as relative adduct labeling values in rats treated with β‐C, α‐T and Aloe, were decreased as compared with the control group at hour 24 (36 h after PH), with a significant difference in the case of the β‐C group (46.4% of the control value). Similarly, all showed a tendency for decrease at hour 48. Furthermore, the levels of CYP1A2, known to be responsible for activation of IQ, showed a significant reduction at hour 24. It is concluded that β‐C, and possibly also α‐T and Aloe, have the potential to reduce IQ‐DNA adduct formation, presumably as a result of decreased formation of active metabolites. The results may explain, at least in part, the previously observed inhibitory effects of these compounds on induction of preneoplastic hepatocellular lesions.