Induction of increased benzpyrene hydroxylase activity by flavones and related compounds.

A study of relationships between the structure of flavones, flavanones, and chalcones and their capacity to induce increased 3,4-benzpyrene (BP) hydroxylase activity in the liver and lung of the rat has been carried out. Appropriate halogenation in creases inducing activity. In the compounds studied, hydroxylation reduces inducing capacity, but the corresponding methoxy compounds are active. Two naturally occurring polymethoxy flavones, tangeretin and nobiletin, have been found to be active inducers of BP hydroxylase activity.