Dietary supplement of isohumulones inhibits the formation of aberrant crypt foci with a concomitant decrease in prostaglandin E2 level in rat colon.
Male Fischer 344 rats were subcutaneously injected with azoxymethane (AOM) twice weekly at a dose of 15 mg/kg and were fed with freeze-dried (FD) samples of beer brewed without hops (non-hops beer), beer with hops at 4 times the amount of regular lager beer (x 4-hops beer), and isomerized hop extract (IHE) for the whole experimental period (I/PI) or for the post-initiation period (PI) only. Feeding FD beer samples at a dose of 1% significantly decreased the number of aberrant cryp foci (ACF) in the PI protocol over five weeks.x4-hops beer showed stronger inhibitory effects on the development of the numbers of aberrant crypts per focus and large ACF with four or more crypts than non-hops beer. Feeding IHE to rats at a dose of 0.01% or 0.05% in either the I/PI or PI experiment significantly reduced the numbers of ACF. Prostaglandin E2 (PGE2) levels in colonic mucosa of AOM-treated rats were significantly reduced by feeding of IHE. PGE2 production induced by lipopolysaccharide/interferon-gamma (LPS/IFN-gamma) in RAW264.7 cells was also reduced by treatment with IHE and isohumulone in a dose-dependent manner. These observations suggest that isohumulones show chemopreventive effects on ACF formation in rat colon by inhibiting the production of PGE2.
Nozawa
Hajime
H
Applied Bioresearch Center, Kirin Brewery Co., Ltd., Takasaki-shi Gunma, Japan. h-nozawa@kirin.co.jp
Nakao
Wakako
W
Zhao
Feng
F
Kondo
Keiji
K
D000818:Animals; D001397:Azoxymethane / Q000008:administration & dosage; D001515:Beer; D002273:Carcinogens / Q000008:administration & dosage; D002460:Cell Line; D003106:Colon / Q000737:chemistry* / Q000378:metabolism; D003110:Colonic Neoplasms / Q000517:prevention & control*; D003517:Cyclopentanes / Q000008:administration & dosage*; D019587:Dietary Supplements; D015232:Dinoprostone / Q000032:analysis* / Q000096:biosynthesis; D007371:Interferon-gamma / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007476:Ionophores / Q000008:administration & dosage; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D011230:Precancerous Conditions / Q000139:chemically induced / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344
D002273:Carcinogens; D003517:Cyclopentanes; D007476:Ionophores; D008070:Lipopolysaccharides; D007371:Interferon-gamma; C081209:isohumulone; D015232:Dinoprostone; D001397:Azoxymethane