Inhibition of endogenous nitrosation of proline in rats by lyophilized beer constituents.
Various amounts of lyophilized beer were administered to rats dosed with proline and sodium nitrite. N-Nitrosoproline (NPRO) excreted in the 24-h urine was monitored as an index of endogenous nitrosation. In vitro formation of NPRO was determined after 15-min incubation of the same precursor solutions. Both in vivo and in vitro nitrosation of proline was inhibited in a dose-dependent fashion by lyophilized beers of different brands; the effects in vitro were most pronounced at pH below 4. The highest inhibitory effect was with beers with a high total polyphenolic content. Our results demonstrate that ingredients present in this widely consumed beverage inhibit endogenous nitrosation.
D000818:Animals; D001515:Beer; D005612:Freeze Drying; D006863:Hydrogen-Ion Concentration; D009573:Nitrites / Q000378:metabolism*; D009602:Nitrosamines / Q000652:urine*; D011392:Proline / Q000378:metabolism*; D051381:Rats; D012977:Sodium Nitrite / Q000378:metabolism*
D009573:Nitrites; D009602:Nitrosamines; D011392:Proline; C010259:nitrosoproline; D012977:Sodium Nitrite