MODERATE INHIBITION OF MUTAGENICITY AND CARCINOGENICITY OF BENZO[A]PYRENE, 1,6-DINITROPYRENE AND 3,9-DINITROFLUORANTHENE BY CHINESE MEDICINAL HERBS

The activity of six Chinese medicinal herbs against the environmental mutagens and carcinogens benzo[a]pyrene (B[a]P), 1,6-dinitropyrene (1, 6-diNP) and 3,9-dinitrofluoranthene (3,9-diNF) was determined. Samples of Prunella spica, Rheum palmatum, Polygonum multiflorum, Agrimonia p ilosa, Ephedra sinica and Teitoutou were tested in an in vitro system. Antimutagenic activity against B[a]P was marked in the presence of ex tracts (boiled for 2 h in a water bath) whereas that against 1,6-diNP and 3,9-diNF varied from 20 to 86%. The differences in inhibition migh t be due to inactivation of metabolic enzymes. An extract of P.multifl orum was divided into ether, ethyl acetate and water soluble fractions , which were tested for antimutagenic activity against B[a]P. The anti mutagenic action of the ethyl acetate soluble fraction was substantial and dose-dependent. Tannins and related compounds were the major comp onents of the extract, of which epigallocatechin, epigallocatechin gal late, epicatechin gallate and tannic acid strongly inhibited the mutag enicity of B[a]P (2.5 mu g/plate) in Salmonella typhimurium TA98 with S9 mix. To confirm the results of the in vitro test system, F344/DuCrj male rats were given a subcutaneous injection of B[a]P. Thereafter, t hey received water extracts of the six Chinese medicinal herbs for 50 weeks and were examined for tumors. The P.multiflorum extract signific antly reduced the tumor incidence.