Effects of flavonoid phytochemicals on cortisol production and on activities of steroidogenic enzymes in human adrenocortical H295R cells

J Steroid Biochem Mol Biol. 2002 Mar;80(3):355-63. doi: 10.1016/s0960-0760(02)00021-3.


Inhibitory effects of flavonoid phytochemicals, flavones, flavonols and isoflavones on cortisol production were examined in human adrenal H295R cells stimulated with di-buthylyl cAMP. In addition, the inhibitory effects of these chemicals on the activity of P450scc, 3beta-HSD type II (3beta-HSD II), P450c17, P450c21 and P45011beta, steroidogenic enzymes involved in cortisol biosynthesis, were examined in the same cells. Exposure to 12.5 microM of the flavonoids 6-hydroxyflavone, 4'-hydroxyflavone, apigenin, daidzein, genistein and formononetin significantly decreased cortisol production (by 6.3, 69.6, 47.5, 26.6, 13.8 and 11.3%, respectively), and biochanin A significantly decreased cortisol production (by 47.3%) at a concentration of 25 microM without any significant cytotoxic effects or changes in cell number. Daidzin, the 7-glucoside of daidzein, did not alter cortisol production by H295R cells at concentrations over 10 microg/ml (24 microM). Daidzein-induced reduction of cortisol production by H295R cells was not inhibited by the estrogen receptor antagonist ICI 182,780. The flavonoids 6-hydroxyflavone, daidzein, genistein, biochanin A and formononetin strongly and significantly inhibited microsomal 3beta-HSD II activity at concentrations from 1 to 25 microM, and I(50) values were estimated to be 1.3, 2, 1, 0.5 and 2.7 microM, respectively. In addition, these flavonoids significantly inhibited microsomal P450c21 activity at 12.5 and/or 25 microM. In addition, 6-hydroxyflavone inhibited activity of microsomal P450c17 and mitochondrial P45011beta at 12.5 and/or 25 microM. Results of Lineweaver-Burk's plot analysis indicate that daidzein is a competitive inhibitor of the activity of 3beta-HSD II and P450c21. K(m) and V(max) values of 3beta-HSD II for DHEA were estimated to be 6.6 microM and 328pmol/minmg protein, respectively. K(m) and V(max) values of P450c21 for progesterone were estimated to be 2.8 microM and 16pmol/minmg protein, respectively. K(i) values of 3beta-HSD II and P450c21 for daidzein were estimated to be 2.9 and 33.3 microM, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Hydroxysteroid Dehydrogenases / antagonists & inhibitors
  • 3-Hydroxysteroid Dehydrogenases / metabolism
  • Adrenal Cortex / cytology
  • Adrenal Cortex / drug effects*
  • Adrenal Cortex / enzymology
  • Cell Line
  • Cytochrome P-450 Enzyme Inhibitors
  • Cytochrome P-450 Enzyme System / metabolism
  • Estradiol / analogs & derivatives*
  • Estradiol / pharmacology
  • Estrogen Receptor Modulators / pharmacology
  • Flavonoids / pharmacology*
  • Fulvestrant
  • Humans
  • Hydrocortisone / biosynthesis*
  • Isoflavones / pharmacology
  • Kinetics


  • Cytochrome P-450 Enzyme Inhibitors
  • Estrogen Receptor Modulators
  • Flavonoids
  • Isoflavones
  • Fulvestrant
  • daidzin
  • Estradiol
  • Cytochrome P-450 Enzyme System
  • 3-Hydroxysteroid Dehydrogenases
  • Hydrocortisone