Yoshifumi Hirose

Mutagenic activities of gentisin and isogentisin from Gentianae radix (Gentianaceae)

The mutagenic activities of 2 hydroxyxanthones, gentisin and isogentisin, obtained from the methanol extract of Gentianae radix (Gentianaceae) were investigated. The methanol extract of Gentianae radix, which showed mutagenicity in the Ames test in Salmonella typhimurium strain TA100 with S9 mix, was fractionated by column chromatography on Sephadex LH-20, and the fractions were purified by preparative TLC and column chromatography on polyamide. 2 mutagenic materials thus obtained, S1 and S2, each gave a single band on TLC. Identification of S1 and S2 was accomplished by comparing the analytical (mps, elementary analyses) and spectral (UV, IR, mass, NMR) results for S1 and S2 with literature data for gentisin and isogentisin. At doses below 10 micrograms, S1 (gentisin) and S2 (isogentisin) had similar specific mutagenic activities. At doses of over 10 to 50 micrograms, the mutagenic activities of S2 and S1 were 19.1 and 6.94 revertants per microgram respectively. This much lower activity of S1 than S2 may be a result of its poor solubility owing to the presence of the OMe group at C-3. The combined yield of S1 and S2 was about 76 mg (40 mg as S1 and 36 mg as S2), which accounted for 76% of the content of mutagenic compounds (100 mg) estimated roughly from the total mutagenic activity in the extract of the starting materials (100 g).

Formation of cyanogen chloride by the reaction of amino acids with hypochlorous acid in the presence of ammonium ion

Abstract Aliphatic amino acids reacted with hypochlorous acid and ammonium ion, i.e. chloramine, to give cyanogen chloride. The yields of cyanogen chloride were, for example, 3 – 4 % from valine, leucine and isoleucine, 11.2 % from serine and 13.7 % from threonine. The nitrogen atom of cyanogen chloride formed from leucine was proved to originate not from chloramine, but from leucine.

Determination of total and combined chlorine in water with the pyridine-pyrazolone reagent

Abstract An improved method for the determination of residual chlorine in water is described. The principle of this method is based on the conversion of total chlorine to cyanogen chloride with potassium cyanide, followed by color development with pyridine-pyrazolone reagent. For the determination of combined chlorine, sodium arsenite was used to eliminate free chlorine. The calibration curves for free and combined chlorine were identical.

Determination of chlorine in air with the pyridine-pyrazolone reagent

Abstract An improved method for the determination of chlorine in air is described. The principle of this method is based on the absorption of chlorine in p-toluenesulfonamide aqueous solution, followed by color development with a pyridine-pyrazolone reagent. Both the chlorine absorbed in the solution and the color developed with the reagent were stable. Positive interference by nitrogen dioxide was not observed.