Effect of benzopyrone derivatives on drug activity and metabolism.

In female rats, zoxazolamine paralysis time and mortality caused by indomethacin were significantly reduced by pretreatment with khellin, 7,8-benzoflavone or rutin. Pretreatment with khellin and 7,8-benzoflavone increased the in vitro zoxazolamine and ethylmorphine metabolism. These results were compared with those obtained by equimolar doses of phenobarbital, pregnenolone-16 alpha-carbonitrile and spironolactone in experiments performed simultaneously. It was concluded: Khellin, 7,8-benzoflavone and rutin increased the body's resistance to drugs via induction of the drug metabolizing enzymes of the liver, this action has about the same magnitude with that of phenobarbital and pregnenolone-16 alpha-carbonitrile. For the benzopyrone derivatives, some common structural features have been indicated as probable structural requirements for drug metabolizing enzyme inductive activity in this group of compounds.