Modulation of N-nitrosomethylbenzylamine metabolism by black raspberries in the esophagus and liver of Fischer 344 rats. Nutr Cancer 2006;54(1):47-57
Date
06/28/2006Pubmed ID
16800772Pubmed Central ID
PMC3015089DOI
10.1207/s15327914nc5401_6Scopus ID
2-s2.0-33746546196 (requires institutional sign-in at Scopus site) 32 CitationsAbstract
Dietary freeze-dried black raspberries (BRBs) inhibit N-nitrosomethylbenzylamine (NMBA)-induced tumorigenesis in the Fischer 344 rat esophagus. To determine the mechanistic basis of the anti-initiating effects of BRBs, NMBA metabolism was studied in esophageal explant cultures and in liver microsomes taken from rats fed with AIN-76A diet or AIN-76A diet containing 5% or 10% BRBs. Five percent and 10% dietary BRBs inhibited NMBA metabolism in explants (26% and 20%) and in microsomes (22% and 28%), but the inhibition was not dose dependent. To identify active inhibitory component(s) in BRBs, esophageal explants and liver microsomes from control rats were treated in vitro with an ethanol extract of BRBs or with individual components of BRBs [ellagic acid (EA) and two anthocyanins (cyanidin-3-glucoside and cyanidin-3-rutinoside)]. NMBA metabolism in explants was inhibited maximally by cyanidin-3-rutinoside (47%) followed by EA (33%), cyanidin-3-glucoside (23%), and the extract (11%). Similarly, in liver microsomes, the inhibition was maximal by cyanidin-3-rutinoside (47%) followed by EA (33%) and cyanidin-3-glucoside (32%). Phenylethylisothiocyanate (PEITC), a potent inhibitor of NMBA tumorigenesis in rat esophagus, was a stronger inhibitor of NMBA metabolism in vivo and in vitro than BRBs or their components. Dietary BRBs and PEITC induced glutathione S-transferase activity in the liver.
Author List
Reen RK, Nines R, Stoner GDMESH terms used to index this publication - Major topics in bold
AnimalsCarcinogens
Diet
Dimethylnitrosamine
Esophagus
Fruit
Glutathione Transferase
Isothiocyanates
Male
Microsomes, Liver
Organ Culture Techniques
Rats
Rats, Inbred F344
Rosaceae
