Article

Dietary supplement of isohumulones inhibits the formation of aberrant crypt foci with a concomitant decrease in prostaglandin E2 level in rat colon

Applied Bioresearch Center, Kirin Brewery Co., Ltd., Takasaki-shi Gunma, Japan.
Molecular Nutrition & Food Research (Impact Factor: 4.6). 08/2005; 49(8):772-8. DOI: 10.1002/mnfr.200500027
Source: PubMed

ABSTRACT

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.

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    • "Iso-α-acids, major bitter components in beer, are converted from α-acids in hops by isomerization during the brewing process. Several studies have established the many health benefits of ingesting iso-α-acids8910. In terms of prevention of obesity, isomerized hop extract, which consists primarily of iso-α-acids, was shown to prevent diet-induced obesity by the modulation of lipid oxidation in the liver via PPARα activation and inhibition of intestinal lipid absorption [11]. "
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