Masahiko Uyeta

Mutagenicity of hydrolysates of tea infusions

Hydrolysates of infusions of green tea and black tea were mutagenic by the Ames test. The tea infusions were prepared by a regular method and were hydrolysed with 1 M HCl, hesperidinase, naringinase and human intestinal bacteria. The hydrolysates were successively extracted with chloroform, diethyl ether and ethyl acetate. The mutagenicities of the extracts were assayed by the Ames test, and the mutagens were analysed by GC-MS. The ether extracts of the hydrolysates of infusions of both green tea and black tea were mutagenic of TA98 and TA100 with or without S9 mix. The most common mutagenic flavonols, kaempferol, quercetin and myricetin, were detected in the extract by GC-MS, and their combined mutagenicity represented about 70% of the whole mutagenic activity in the extract.

Mutagenicity of hydrolysates of citrus fruit juices

Hydrolysates of citrus fruit juice were mutagenic according to the Ames test. The citrus fruit juices were hydrolysed with 1 M HCl, hesperidinase, naringinase and human intestinal bacteria. The hydrolysates were successively extracted with n-hexane, chloroform, diethyl ether and ethyl acetate. The mutagenicities of extracts were assayed by the Ames test, and the mutagens were analysed by gas chromatography and mass spectrometry (GC-MS). Mutagenicities of hydrolysates of citrus fruit juice were found in both the chloroform extracts and the ether extracts. The chloroform extracts were mutagenic to TA98 and TA100 with S9 mix, and the ether extracts were mutagenic to TA98 and TA100 with or without S9 mix. Some known flavonols such as kaempferol and quercetin were detected in the extracts of the hydrolysates by GC-MS. It is suggested that the mutagenicity of the extracts originated from those flavonols in the citrus fruit juice.

Photoreaction of Monochlorobenzene under Ultraviolet Irradiation

The photolysis of monochlorobenzene by ultraviolet irradiation was investigated and found to yield monochlorinated biphenyls, biphenyl, and benzene. The amounts of these products increased with reaction time up to 20 hours. The yields of 2-, 3- and 4-chlorobiphenyl, biphenyl and benzene in monochlorobenzene were 708 ppm, 965 ppm, 1012 ppm, 226 ppm and 410 ppm, respectively, after 20 hours, but subsequent increases were relatively slow. One possibility is that monochlorinated biphenyls formed from monochlorobenzene are gradually decomposed by further irradiation. The photostability of monochlorinated biphenyls and biphenyl was in the order : biphenyl »4-chlorobiphenyl>3-chlorobiphenyl>2-chlorobiphenyl.