Inhibition of 11beta-hydroxysteroid dehydrogenase by bioflavonoids and their interaction with furosemide and gossypol.

Inhibition of 11beta-hydroxysteroid dehydrogenase (11beta-OHSD) can cause a mineralocorticoid effect. This enzyme, in guinea pig renal cortex microsomes in vitro, is inhibited by quercetin, tea polyphenols, furosemide, and gossypol. The dietary polyphenols, quercetin and tea polyphenols, interact with furosemide to enhance its 11beta-OHSD inhibitory effect. Tea polyphenols added to the effect of gossypol. We conclude that the diet contains inhibitors of 11beta-OHSD that can alter the activity of this enzyme and may modify the degree of endogenous mineralocorticoid activity.