Inhibition of azoxymethane-induced DNA adduct formation by

Aloe arborescens var. Natalensis

Kan Shimpo, Takeshi Chihara, Hidehiko Beppu, Chikako Ida, Takaaki Kaneko, Motoyuki Hoshino, Hiroshi Kuzuya

Research output: Contribution to journalArticle

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Abstract

To clarify the possible mechanisms of inhibition of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in the rat colorectum by freeze-dried whole leaves of Aloe arborescens var. natalensis (Kidachi aloe) (hereinafter referred to as ALOE) and commercial crude aloin (Sigma A-0451; from Curacao aloe) (hereinafter ALOIN), we studied the effects of ALOE and ALOIN on the formation of AOM-induced DNA adducts (O6-methylguanine; O6-MeG) in rats. Male F344 rats (4 weeks old) were fed a basal diet, or experimental diets containing 5%ALOE or 0.25%ALOIN for 5 weeks. All rats were injected s.c. twice with 15 mg/kg AOM, once at the end of week 1, and once at the end of week 2. The animals were sacrificed 6 hours after the second injection to analyze DNA adducts (O6-MeG) in the colorectum. Dietary administration of ALOE significantly inhibited the O6-MeG levels (50% reduction) compared with controls, whereas the O6-MeG levels in the ALOIN-fed rats showed a tendency to decrease (by 30%), although not significantly. In this study, we also measured the enzyme activity and mRNA level of cytochrome (CYP) 2E1, known to be responsible for the activation of AOM, in rat liver. ALOE-fed rats showed significantly reduced CYP2E1 enzymatic activity (27% reduction) compared with controls. On the other hand, the activity in ALOIN-fed rats tended to decrease by 11%, although not significantly. The CYP2E1 mRNA levels in ALOE- and ALOIN-fed rats were slightly reduced (9.7% and 5.2%, respectively). These results may explain, at least in part, the previously observed inhibitory effects of ALOE and ALOIN, especially ALOE on AOM-induced ACF formation in the rat colorectum.

Original languageEnglish
Pages (from-to)247-251
Number of pages5
JournalAsian Pacific Journal of Cancer Prevention
Volume4
Issue number3
Publication statusPublished - 01-01-2003

Fingerprint

Azoxymethane
Aloe
DNA Adducts
Cytochrome P-450 CYP2E1
Aberrant Crypt Foci
Diet
Messenger RNA
Inbred F344 Rats
Cytochromes
Netherlands

All Science Journal Classification (ASJC) codes

  • Epidemiology
  • Oncology
  • Public Health, Environmental and Occupational Health
  • Cancer Research

Cite this

Shimpo, Kan ; Chihara, Takeshi ; Beppu, Hidehiko ; Ida, Chikako ; Kaneko, Takaaki ; Hoshino, Motoyuki ; Kuzuya, Hiroshi. / Inhibition of azoxymethane-induced DNA adduct formation by : Aloe arborescens var. Natalensis. In: Asian Pacific Journal of Cancer Prevention. 2003 ; Vol. 4, No. 3. pp. 247-251.
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title = "Inhibition of azoxymethane-induced DNA adduct formation by: Aloe arborescens var. Natalensis",
abstract = "To clarify the possible mechanisms of inhibition of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in the rat colorectum by freeze-dried whole leaves of Aloe arborescens var. natalensis (Kidachi aloe) (hereinafter referred to as ALOE) and commercial crude aloin (Sigma A-0451; from Curacao aloe) (hereinafter ALOIN), we studied the effects of ALOE and ALOIN on the formation of AOM-induced DNA adducts (O6-methylguanine; O6-MeG) in rats. Male F344 rats (4 weeks old) were fed a basal diet, or experimental diets containing 5{\%}ALOE or 0.25{\%}ALOIN for 5 weeks. All rats were injected s.c. twice with 15 mg/kg AOM, once at the end of week 1, and once at the end of week 2. The animals were sacrificed 6 hours after the second injection to analyze DNA adducts (O6-MeG) in the colorectum. Dietary administration of ALOE significantly inhibited the O6-MeG levels (50{\%} reduction) compared with controls, whereas the O6-MeG levels in the ALOIN-fed rats showed a tendency to decrease (by 30{\%}), although not significantly. In this study, we also measured the enzyme activity and mRNA level of cytochrome (CYP) 2E1, known to be responsible for the activation of AOM, in rat liver. ALOE-fed rats showed significantly reduced CYP2E1 enzymatic activity (27{\%} reduction) compared with controls. On the other hand, the activity in ALOIN-fed rats tended to decrease by 11{\%}, although not significantly. The CYP2E1 mRNA levels in ALOE- and ALOIN-fed rats were slightly reduced (9.7{\%} and 5.2{\%}, respectively). These results may explain, at least in part, the previously observed inhibitory effects of ALOE and ALOIN, especially ALOE on AOM-induced ACF formation in the rat colorectum.",
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Shimpo, K, Chihara, T, Beppu, H, Ida, C, Kaneko, T, Hoshino, M & Kuzuya, H 2003, 'Inhibition of azoxymethane-induced DNA adduct formation by: Aloe arborescens var. Natalensis', Asian Pacific Journal of Cancer Prevention, vol. 4, no. 3, pp. 247-251.

Inhibition of azoxymethane-induced DNA adduct formation by : Aloe arborescens var. Natalensis. / Shimpo, Kan; Chihara, Takeshi; Beppu, Hidehiko; Ida, Chikako; Kaneko, Takaaki; Hoshino, Motoyuki; Kuzuya, Hiroshi.

In: Asian Pacific Journal of Cancer Prevention, Vol. 4, No. 3, 01.01.2003, p. 247-251.

Research output: Contribution to journalArticle

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T1 - Inhibition of azoxymethane-induced DNA adduct formation by

T2 - Aloe arborescens var. Natalensis

AU - Shimpo, Kan

AU - Chihara, Takeshi

AU - Beppu, Hidehiko

AU - Ida, Chikako

AU - Kaneko, Takaaki

AU - Hoshino, Motoyuki

AU - Kuzuya, Hiroshi

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