ANTIMUTAGENICITY OF TOCHU TEA (AN AQUEOUS EXTRACT OF EUCOMMIA-ULMOIDES LEAVES) .1. THE CLASTOGEN-SUPPRESSING EFFECTS OF TOCHU TEA IN CHO CELLS AND MICE

The suppressing effect of crude extracts of Tochu tea, an aqueous extr act of Eucommia ulmoides leaves and a popular beverage in Japan, on th e induction of chromosome aberrations in CHO cells and mice was studie d. When CHO cells were treated with Tochu tea crude extract after MMC treatment, the frequency of chromosome aberrations was reduced. Out of 17 Tochu tea components, 5 irridoids (geniposidic acid, geniposide, a sperulosidic acid, deacetyl asperulosidic acid, and asperuloside) and 3 phenols (pyrogallol, protocatechuic acid, and p-trans-coumaric acid) were found to have anticlastogenic activity. Since the anticlastogeni c irridoids had an a-unsaturated carbonyl group, this structure was co nsidered to play an important role in the anticlastogenicity. The anti clastogenic effect of Tochu tea extracts was examined in mice using a micronucleus assay. When mice received 1.0 mi 4% Tochu tea extract by oral gavage 6 h before intraperitoneal injection of MMC, a decrease in the frequency of micronuclei was observed. This decrease was not due to a delay in the maturation of micronucleated reticulocytes.