title: Inhibitory effects of isoflavonoids on rat prostate testosterone 5α-reductase.
abstract: Testosterone 5α-reductase inhibitors represent important therapeutic drugs for use against androgen-dependent diseases such as benign prostatic hyperplasia, male pattern baldness, and acne. We have searched for inhibitors of rat prostate testosterone 5α-reductase in the cultured broths of many kinds of soil bacteria, and have found that cultured soybean-casein digest broths of certain bacterial strains have a potent inhibitory effect on the enzyme. We tested 10 selected isoflavonoids, including isoflavones and O-methylated isoflavones, for inhibitory effects on rat prostate testosterone 5α-reductase to determine the important structural elements for inhibition of the enzyme. Genistein, biochanin A, equol, and 3',4',7-trihydroxyisoflavone showed considerably higher inhibitory effects whereas daidzein, formononetin, glycitein, prunetin, ipriflavone, and 4',7-dimethoxyisoflavone showed lower inhibitory effects. The IC(50) values of genistein, biochanin A, equol, 3',4',7-trihydroxyisoflavone, and riboflavin, a positive control, for rat prostate testosterone 5α-reductase were 710 μm, 140 μm, 370 μm, 690 μm, and 17 μm, respectively. Daidzein, genistein, biochanin A, formononetin, and equol are already known to be testosterone 5α-reductase inhibitors, but this is the first characterization of 3',4',7-trihydroxyisoflavone as an inhibitor of the enzyme.
authors.affiliation: Department of Herbal Pharmaceutical Engineering, College of Herbal Bio-industry, Daegu Haany University, Daegu, Republic of Korea.
authors.forename: Mijeong
authors.initials: M
authors.lastname: Bae
authors.forename: Mijin
authors.initials: M
authors.lastname: Woo
authors.forename: Irawan Wijaya
authors.initials: IW
authors.lastname: Kusuma
authors.forename: Enos Tangke
authors.initials: ET
authors.lastname: Arung
authors.forename: Chae Ha
authors.initials: CH
authors.lastname: Yang
authors.forename: Yong-ung
authors.initials: YU
authors.lastname: Kim
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D058891:5-alpha Reductase Inhibitors / Q000494:pharmacology*; D000818:Animals; D001419:Bacteria; D002364:Caseins; D020128:Inhibitory Concentration 50; D007529:Isoflavones / Q000494:pharmacology*; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D011467:Prostate / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012987:Soil; D013025:Glycine max / Q000737:chemistry*
chemical_list: D058891:5-alpha Reductase Inhibitors; D002364:Caseins; D007529:Isoflavones; D010936:Plant Extracts; D012987:Soil; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; C061213:3',4',7-trihydroxyisoflavone