The effect of teas on the in vitro mutagenic potential of heterocyclic aromatic amines

Fractionation of green tea extracts: correlation of antimutagenic effect with flavanol content

“…Recent studies emanating from this laboratory have shown that black and green tea, despite their markedly di †erent Ñavanol content, possess the same degree of antimutagenic activity against a number of indirect-acting mutagens, indicating that Ñavanols are unlikely to be the principal component of tea expressing its antimutagenic activity or that the theaÑavins and thearubigins are similarly active in this respect (Bu-Abbas et al 1996). Moreover, instant teas, containing only traces of Ñavanoids, were at least as e †ective as green tea in suppressing the mutagenicity of heterocyclic amines (Constable et al 1996 ;Stavric et al 1996). In contrast, Yen and Chen (1996) reported a correlation between the content of Ñavanol and the ability of teas to inhibit the mutagenicity of IQ in the Ames test, especially when the tester bacterial strain employed was TA100.…”

“…Similarly, aqueous extracts of green tea e †ectively suppressed the mutagenicity of a variety of indirect-acting * To whom correspondence should be addressed. mutagens including nitroso compounds, aromatic and heterocyclic amines, mycotoxins and polycyclic aromatic hydrocarbons Chen 1996, 1994 ;BuAbbas et al 1994 ;Apostolides et al 1996 ;Stavric et al 1996). At least two mechanisms appear to mediate the antimutagenic e †ects of green tea (Bu-Abbas et al 1994) : inhibition of the cytochrome P450-dependent bioactivation of chemical carcinogens and, to a lesser degree, scavenging of the reactive intermediates, thus preventing them from interacting with DNA.…”

Heterocyclic Aromatic Amines Heterocomplexation with Biologically Active Aromatic Compounds and Its Possible Role in Chemoprevention

“…It was demonstrated that caffeine-rich beverages, such as different types of tea [73][74][75][76] as well as coffee [77], can inhibit HCAs biological activity. Moreover, decaffeinated tea was shown to be less effective in reducing PhIP mutagenic activity than regular tea [75].…”

Heterocyclic amines: Chemistry and health

“…It is also probable that other components in soy sauce such as minerals interact with the phytochemicals to produce a different net effect. Tea extracts have been extensively studied, but mainly for their effects on HA-induced mutagenicity/carcinogenicity [250,251] and their bioavailability [252]. Moreover, the fact that tea or its extract is a rare ingredient in culinary dishes needs to be considered when extrapolating these findings to practical benefits for humans.…”