Preventive effects of a flavonoid myricitrin on the formation of azoxymethane-induced premalignant lesions in colons of rats.
The preventive effect of dietary exposure to a flavonoid myricitrin of azoxymethane (AOM)-induced aberrant crypt foci (ACF) and beta-catenin-accumulated crypts (BCAC) formation was investigated in male F344 rats. Thirty-four rats were divided randomly into five experimental groups. Rats in groups 1-3 were given subcutaneous injections of AOM (15 mg/kg body weight) once a week for 3 weeks. Starting 1 week before the first injection of AOM, rats in groups 2 and 3 were fed a diet containing 500 or 1000 ppm myricitrin, respectively, for 11 weeks. Rats in group 4 were fed a diet containing 1000 ppm myricitrin. Rats in groups 1 and 5 were given the basal diet alone during the study. The experiment was terminated 11 weeks after the start. The frequency of ACF per colon in group 3 treated with AOM and 1000 ppm myricitrin was significantly lower than that in group 1 treated with AOM alone (p<0.01). Furthermore, dietary myricitrin at both doses (groups 2 and 3) significantly inhibited the formation of BCAC when compared to group 1 (p<0.05). These results indicate that myricitrin had possible chemopreventive effects in the present short-term colon carcinogenesis bioassays and suggest that longer exposure may cause suppression of tumor development.
Asano
Nami
N
Department of Tumor Pathology, Graduate School of Medicine, Gifu University, Gifu 501-1194, Japan.
Kuno
Toshiya
T
Hirose
Yoshinobu
Y
Yamada
Yasuhiro
Y
Yoshida
Koujirou
K
Tomita
Hiroyuki
H
Nakamura
Yoshiyuki
Y
Mori
Hideki
H
D000818:Animals; D001397:Azoxymethane / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D004032:Diet; D005419:Flavonoids / Q000494:pharmacology*; D008297:Male; D011230:Precancerous Conditions / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344; D051176:beta Catenin / Q000494:pharmacology
D002273:Carcinogens; D005419:Flavonoids; D051176:beta Catenin; C008577:myricitrin; D001397:Azoxymethane