Antimutagenic Effects of Polymethoxy Flavonoids of Citrus unshiu.

Citrus fiits have been used as edible fruit and traditional medicine for various diseases such as cancer. In the courses of our study to find antimutagens, we have found that.the ethanolic extract of the peel of Citrus unshiu Marc showed antimutagenic effects against several mutagens in the Ames test using Salmonella typhimurium TA98 strain. Three polymethoxy flavonoids, nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone, and tangeretin, were identified in the extract as major constituents. These three polymethoxy flavonoids showed antimutagenic effects in the Ames test in vitro and in the micronucleus test in vivo.