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.