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Dietary supplement of isohumulones inhibits the formation of aberrant crypt foci with a concomitant decrease in prostaglandin E2 level in rat colon
Author(s) -
Nozawa Hajime,
Nakao Wakako,
Zhao Feng,
Kondo Keiji
Publication year - 2005
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200500027
Subject(s) - azoxymethane , aberrant crypt foci , prostaglandin e2 , chemistry , lipopolysaccharide , prostaglandin , crypt , pi , prostaglandin e , dose dependence , endocrinology , medicine , food science , biology , biochemistry , colorectal cancer , colonic disease , cancer , carcinogenesis , gene
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 (×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.×4‐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‐γ (LPS/IFN‐γ) 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.