title: The estrogenic properties of Danggui Buxue Tang, a Chinese herbal decoction, are triggered predominantly by calycosin in MCF-7 cells.
abstract: BACKGROUND
  Danggui Buxue Tang (DBT), a Chinese herbal decoction containing Astragali Radix (AR; roots of Astragalus memebranaceus (Fisch.) Bunge var. mongholicus (Bunge) Hsiao) and Angelicae Sinensis Radix (ASR; roots of Angelica sinensis Oliv.) at a weight ratio of 5:1, is used to improve menopausal syndromes in women. Several lines of evidence indicate that DBT has strong estrogenic property; however, the action mechanism of this herbal decoction is not known. Calycosin, a major flavonoid in AR, shares similar structure with β-estradiol, and thus which is hypothesized to be the key compound of DBT in responsible for such estrogenic properties.
  
  
  OBJECTIVE
  We aimed to determine the role of calycosin in DBT in terms of its estrogenic functions by the creation of calycosin-depleted DBT (DBTΔcal) and calycosin-added DBT (DBT+cal) herbal extracts.
  
  
  METHODS
  The signalings triggered by DBT∆cal, DBT+cal, and parental DBT were compared in cultured MCF-7 cells by determining: (i) the activation of estrogen responsive element; (ii) the phosphorylation of estrogen receptor α (ERα); and (iii) the phosphorylation of Erk1/2. The DBT-induced responses were in dose- and/or time-dependent manners.
  
  
  RESULTS
  The estrogenic signals triggered by DBT were markedly reduced in DBTΔcal, and in contrast the addition of calycosin in DBT, i.e. DBT+cal, enhanced the responses by 2-5 folds; however, calycosin alone did not show such properties. In parallel, the DBT-induced responses could be significantly blocked by inhibitors for estrogen receptor and mitogen activated protein kinases.
  
  
  CONCLUSIONS
  Thus, we hypothesize that calycosin is an indispensable chemical in DBT, and which plays a linker in orchestrating multi-components of DBT as to achieve the maximal estrogenic functions. These discoveries should be invaluable in drug development and in investigating the modernization of traditional Chinese medicine from a new perspective.
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Amy G W
authors.initials: AG
authors.lastname: Gong
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Kei M
authors.initials: KM
authors.lastname: Lau
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Miranda L
authors.initials: ML
authors.lastname: Xu
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Huang Q
authors.initials: HQ
authors.lastname: Lin
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Tina T X
authors.initials: TT
authors.lastname: Dong
authors.affiliation: Department of Biology, Hanshan Normal University, Chaozhou, Guangdong 521041, China.
authors.forename: Ken Y Z
authors.initials: KY
authors.lastname: Zheng
authors.affiliation: Beijing Friendship Hospital, Capital Medical University, No. 95, Yongan Road, Beijing 100050, China.
authors.forename: K J
authors.initials: KJ
authors.lastname: Zhao
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China. Electronic address: botsim@ust.hk.
authors.forename: Karl W K
authors.initials: KW
authors.lastname: Tsim
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D061986:MCF-7 Cells; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D008517:Phytotherapy; D010946:Plants, Medicinal; D020218:Response Elements / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection
chemical_list: D004365:Drugs, Chinese Herbal; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D004967:Estrogens; D007529:Isoflavones; C477279:danggui buxue decoction; C121707:7,3'-dihydroxy-4'-methoxyisoflavone; D004958:Estradiol; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3
keywords: Calycosin; Chemical depletion; Danggui Buxue Tang; Estrogenic effects; Phosphorylation