Effect of dietary caffeic and chlorogenic acids on in vivo xenobiotic enzyme systems.

The plant phenols chlorogenic and caffeic acids were tested for their affinity to alter hepatic and intestinal xenobiotic Phase I and Phase II enzyme activities in mice. Mice were fed isocaloric and isonitrogenous powdered diets containing 0 and 0.2% caffeic and chlorogenic acids, respectively. Animals pre-treated with benzo(a)pyrene (B(a)P) were sacrificed 18 h after an oral dose (50 mg/kg Bwt). B(a)P induced animals exhibited higher (p < 0.05) microsomal AHH, UDPGT, P-450 and cytosolic GST liver enzyme activities. The presence of these phenolics in the diet was shown to have little effect in modulating hepatic xenobiotic activating-detoxification enzymes. The dietary intake of caffeic and chlorogenic acids was particularly evident with intestinal xenobiotic AHH and GST enzyme activity. These data indicate that the presence of caffeic and chlorogenic acids in the diet may have an integral role in modulating the carcinogenic potential of reactive xenobiotics such as B(a)P.