Yoshimichi Sakai

Inhibitory action of peony root extract on the mutagenicity of benzo[a]pyrene

The inhibitory effects of peony root extract on the mutagenicity of benzo[a]pyrene (B [a]p) have been investigated in the Salmonella typhimurium reversion test. Four kinds of experiments were performed: direct chemical reaction (1) between peony root extract and B [a]p, and (2) between peony root extract and active metabolite(s) of B [a]p, (3) inhibition of metabolic processes of B[a]p with S9 mix, and (4) inhibition of activation on mutagenicity. Peony root extract interfered with the action of enzymes in the S9 mix, and inactivated the activity of B[a]p metabolites. The bio-antimutagenic effect was assayed by reversion in Salmonella typhimurium TA98 and TA100.

Effects of medicinal plant extracts from Chinese herbal medicines on the mutagenic activity of benzo[a]pyrene.

The effects of medicinal plants on the mutagenicity of benzo[a]pyrene were studied with Salmonella typhimurium tester strains. The chosen medicinal plants are very frequently used as Chinese herbal medicines. Each medicinal plant was extracted with hot water, which is similar to the method used in Chinese medicinal treatment. Cinnamomi cortex, Rhei rhizoma, Scutellariae radix and Rehmanniae radix were found to decrease the mutagenic activity of benzo[a]pyrene. Atractylodis rhizoma also reduced the mutagenicity of benzo[a]pyrene, but this was not certain, because it showed a killing effect on the cell survival test. Bupleuri radix and Aurantii nobilis pericarpium had an enhancing effect, but then neither of these extracts is itself mutagenic. Each medicinal plant extract showed a different effect on the mutagenicity of benzo[a]pyrene. These effects were classified into 5 types: (I) decreasing effect, (II) killing effect, (III) enhancing effect, (IV) enhancing and decreasing effect and (V) inactive.

Antimutagenicity of extracts from crude drugs in Chinese medicines.

The antimutagenicity of extracts from crude drugs was studied by the Ames bioassay system. The crude drugs chosen were medical plants used very frequently as Chinese medicines. Each crude drug was extracted with hot water similar to the method of Chinese medical treatment. Antimutagenicity of the extract was found with 4 kinds of crude drugs, Paeoniae radix, Bupleuri radix, Hoelen and Glycyrrhizae radix. Each extract of the crude drug showed a different type of antimutagenic action from the others.

Determination of the 8-methyl ether of xanthurenic acid in human serum by high-performance liquid chromatography with fluorescence detection

We developed a simple and sensitive assay for the 8-methyl ether of xanthurenic acid in serum by high-performance liquid chromatography with fluorescence detection (excitation at 340 nm, emission at 450 nm). The compound under study in serum samples was extracted with Sep-Pak C18 cartridge and the extract was applied to an octadecylsilane-bonded column (Nucleosil 5C18, 150 x 4 mm I.D.). The mobile phase used was a mixture of 0.05 M sodium acetate buffer (pH 6.0), containing 5 mM sodium 1-octanesulfonate and 0.1 mM Na2EDTA, and acetonitrile (93:7, v/v). The 8-methyl ether of xanthurenic acid from serum samples was sufficiently separated to be clearly distinguishable. The quantification limit was 2 x 10(-14) mol, which was sensitive enough to detect 8-methyl ether of xanthurenic acid in serum from normal subjects. The method was applied to samples from patients with deficiency in tryptophan metabolism, xanthurenic acid/3-hydroxy kynurenineuria and showed a striking elevation in serum 8-methyl ether of xanthurenic acid.