title: Kanamycin inhibits daidzein metabolism and abilities of the metabolites to prevent bone loss in ovariectomized mice.
abstract: BACKGROUND
  Daidzein is an isoflavone derived from soybeans that exerts preventive effects on bone loss in ovariectomized (OVX) animals. These effects have been correlated with increasing serum equol levels. In the present study, we investigated the effects of antibiotic intake on equol metabolism from daidzein, and the corresponding levels of bone loss in OVX mice.
  
  
  METHODS
  Eight-week-old female ddY mice (n = 42) were either ovariectomized (OVX) or subjected to a sham operation (sham). OVX mice were then divided into six dietary subgroups: control diet (control), 0.3 % kanamycin diet (KN), 0.1 % daidzein diet (Dz), 0.1 % daidzein and 0.0375 % kanamycin diet (Dz+KN3.75), 0.1 % daidzein and 0.075 % kanamycin diet (Dz+KN7.5), and 0.1 % daidzein and 0.3 % kanamycin diet (Dz+KN30). The mice were fed their respective diets for 4 weeks.
  
  
  RESULTS
  Uterine weight and femoral bone mineral density (BMD) were significantly lower in the OVX mice compared in the sham mice. No significant differences in uterine weight were observed among all OVX dietary subgroups. The Dz subgroup was found to exhibit higher plasma equol and O-desmethylangolensin (O-DMA) concentrations, as well as greater femoral BMD, compared to all other OVX subgroups. Furthermore, when compared to the Dz group, kanamycin intake decreased plasma equol and O-DMA concentrations, as well as femoral BMD in the OVX mice.
  
  
  CONCLUSIONS
  These results suggest that kanamycin intake inhibited the conversion of daidzein to equol and O-DMA, blocking the preventive effects of daidzein on bone loss in OVX mice. Therefore, the bone-protective effects of daidzein intake may be predominantly associated with increased plasma concentrations of either equol or O-DMA.
authors.affiliation: Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Katsumata
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation and Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan.|Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Fujioka
authors.affiliation: Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
authors.forename: Shungo
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation and Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ishimi
authors.affiliation: Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan. mari@nodai.ac.jp.
authors.forename: Mariko
authors.initials: M
authors.lastname: Uehara
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001711:Biotransformation; D001835:Body Weight / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects*; D004032:Diet; D004195:Disease Models, Animal; D060754:Equol / Q000097:blood; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000037:antagonists & inhibitors / Q000097:blood; D007612:Kanamycin / Q000009:adverse effects*; D051379:Mice; D009929:Organ Size / Q000187:drug effects; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D010052:Ovariectomy / Q000009:adverse effects*; D048789:Phytoestrogens / Q000008:administration & dosage* / Q000037:antagonists & inhibitors / Q000097:blood; D014599:Uterus / Q000187:drug effects / Q000378:metabolism
chemical_list: D007529:Isoflavones; D048789:Phytoestrogens; D060754:Equol; D007612:Kanamycin; C004742:daidzein; C050052:O-desmethylangolensin
keywords: Bone mineral density; Daidzein; Equol; Kanamycin; O-desmethylangolensin; Ovariectomy