Inhibition of azoxymethane-induced aberrant crypt foci formation in rat colorectum by whole leaf Aloe arborescens Miller var. natalensis Berger.
We examined the modifying effect of whole-leaf Aloe arborescens Miller var. natalensis Berger (designated as 'ALOE') on azoxymethane (AOM)-induced aberrant crypt foci (ACF), putative preneoplastic lesions, in the rat colorectum. Male F344 rats (4 weeks old) were fed the basal diet, or experimental diets containing 1% or 5% ALOE for 5 weeks. One week later, all rats except those in the vehicle-treated groups were injected s.c. with AOM (15 mg/kg, once weekly for 3 weeks). At 9 weeks of age, all the rats were killed, and the colorectum and liver were evaluated for ACF and cytosolic quinone reductase (QR; a phase 2 enzyme), respectively. In rats given AOM and ALOE (1% or 5% in diet) the numbers of ACF/colorectum, aberrant crypts/colorectum, aberrant crypts/focus and large ACF/colorectum were significantly decreased compared with those of rats given AOM alone (all p < 0.01). No ACF were found in rats treated without AOM. In addition, ALOE significantly increased cytosolic QR activity in the liver (p < 0.01). These results indicated that ALOE inhibited the development of AOM-induced ACF in the rat colorectum, with increased QR activity in the liver, and therefore suggested that ALOE might have a chemopreventive effect against colon carcinogenesis at least in the initiation stage.
Shimpo
K
K
Fujita Memorial Institute of Pharmacognosy, Fujita Health University, Hisai, Mie 514-1296, Japan.
Chihara
T
T
Beppu
H
H
Ida
C
C
Kaneko
T
T
Nagatsu
T
T
Kuzuya
H
H
D000504:Aloe; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001397:Azoxymethane; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D011230:Precancerous Conditions / Q000139:chemically induced / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344
D000970:Antineoplastic Agents; D010936:Plant Extracts; D016660:NAD(P)H Dehydrogenase (Quinone); D001397:Azoxymethane