title: Inhibition of 1, 2-dimethylhydrazine-induced mucin-depleted foci and O⁶-methylguanine DNA adducts in the rat colorectum by boiled garlic powder.
abstract: The scavenging capacity of reactive oxygen species, such as hydroxyl radicals, is reported not to decrease in boiled garlic (an odorless garlic preparation). We therefore examined the modifying effect of boiled garlic powder (BGP) on 1,2-dimethylhydrazine-induced mucin-depleted foci (MDF) and aberrant crypt foci (ACF), preneoplastic lesions, in the rat colorectum. Male F344 rats (5 weeks old) were fed a basal diet, or experimental diets containing 5% or 1% BGP for 5 weeks. One week later, all rats were injected s.c. with DMH (40 mg/kg, once weekly for 2 weeks). At 10 weeks of age, all the rats were sacrificed, and the colorectum was evaluated for MDF and ACF. In rats given DMH and the 5% or 1% BGP diets (Groups 2 and 3), the numbers of MDF decreased significantly in a dose-dependent manner, compared with the DMH and basal diet value (Group 1) (p<0.01). The numbers of ACF in Group 2, but not Group 3, showed a non-significant tendency to decrease. Next, the effects of BGP on the formation of DMH-induced O6-methylguanine (O6-MeG) DNA adducts in rats were studied. Male F344 rats (5 weeks old) were fed the basal diet, or 10% BGP diet for 5 weeks. All rats were injected i.p. once with 40 mg/kg DMH at the end of week 5. The animals were sacrificed 6 hours after DMH injection to analyze the O6-MeG DNA adducts in the colorectal mucosa. Dietary administration of BGP significantly inhibited the O6-MeG DNA adduct levels in the colorectal mucosa, compared with the controls (p<0.01). These results suggested that BGP may exert chemopreventive effects against colon carcinogenesis at least in the initiation stage.
authors.affiliation: Fujita Memorial Nanakuri Institute, Fujita Health University, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Chihara
authors.forename: Kan
authors.initials: K
authors.lastname: Shimpo
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kaneko
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Beppu
authors.forename: Kenmei
authors.initials: K
authors.lastname: Mizutani
authors.forename: Takashi
authors.initials: T
authors.lastname: Higashiguchi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sonoda
mesh_terms: D019813:1,2-Dimethylhydrazine / Q000494:pharmacology*; D058739:Aberrant Crypt Foci / Q000188:drug therapy; D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000378:metabolism; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000517:prevention & control; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005737:Garlic / Q000737:chemistry*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D008297:Male; D009077:Mucins / Q000172:deficiency / Q000378:metabolism*; D011230:Precancerous Conditions / Q000139:chemically induced / Q000517:prevention & control; D051381:Rats; D011916:Rats, Inbred F344; D017382:Reactive Oxygen Species / Q000378:metabolism; D012007:Rectum / Q000187:drug effects* / Q000378:metabolism
chemical_list: D018736:DNA Adducts; D009077:Mucins; D017382:Reactive Oxygen Species; D006147:Guanine; C008449:O-(6)-methylguanine; D019813:1,2-Dimethylhydrazine