K. Horikawa et al., MODERATE INHIBITION OF MUTAGENICITY AND CARCINOGENICITY OF BENZO[A]PYRENE, 1,6-DINITROPYRENE AND 3,9-DINITROFLUORANTHENE BY CHINESE MEDICINAL HERBS, Mutagenesis, 9(6), 1994, pp. 523-526
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.