Activation of rutin by human oral bacterial isolates to the carcinogen-mutagen quercetin.
Oral streptococci, isolated from the mouths of 2 healthy subjects, hydrolysed innocuous rutin, a flavonoid glycoside, to its genotoxic aglycon quercetin, in vitro. The isolates were identified as Streptococcus milleri. The glycosidase, rutinase, was studied in cell-free extracts derived from one of the isolates, grown anaerobically in batch cultures by the use of a bioassay, the Ames test, in which S-9 was replaced by the cell-free extracts. This streptococcal rutinase was: constitutive, partly inducible, cytosolic, most active for rutin and most active at pH 6.5. Type-culture collection strains of other oral streptococci (Streptococcus salivarius ATCC 25975 and Streptococcus mutans strain 6715-10) showed no capacity for rutin degradation. A hypothesis for a novel role of the oral microflora in a disease process other than caries and periodontal disease, namely intra-oral cancer, is presented. The possibility of a bacterial liberation of the genotoxic quercetin in situ could be but one example of its involvement in the local carcinogenic process.
D002273:Carcinogens / Q000378:metabolism*; D005419:Flavonoids / Q000096:biosynthesis*; D006801:Humans; D006868:Hydrolysis; D009055:Mouth / Q000382:microbiology*; D011794:Quercetin / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000378:metabolism; D012431:Rutin / Q000378:metabolism*; D013291:Streptococcus / Q000201:enzymology* / Q000302:isolation & purification
D002273:Carcinogens; D005419:Flavonoids; C012526:quercitrin; D012431:Rutin; D011794:Quercetin