title: [Study on Precursors for Synthesis of Anthraquinone Metabolites from Rheum tanguticum].
abstract: OBJECTIVE
  To explore the potential precursors of the anthraquinone metabolites from Rheum tanguticum and preliminanly identify the synthesis pathway thereof.
  
  
  METHODS
  Sterile seedlings sprouted from the seeds of Rheum tanguticum were chosen as materials for inducing callus. The effects of different precursors and feeding duration on the callus of Rheum tanguticum and the anthraquinone yield in adult rheum were studied.
  
  
  RESULTS
  The greatest improvement of anthraquinone yield was achieved by acetic acid, increasing 43. 9% for the callus and 45. 8% in the adult rheum; the second greatest improvement was achieved by malonic acid, increasing 15. 8% for the callus and only 3. 6% in the adult rheum. The yield of anthraquinone was not influenced significantly by benzoic acid and p-benzoquinone, and in contrast, was inhibited in some degree by shikimic acid and α-ketoglutaric acid. A suitable feeding duration was 36 h, which worked well for the effects of precursors.
  
  
  CONCLUSIONS
  The precursor for synthesis of anthraquinone metabolites from Rheum tan- guticum is acetic acid, which improves the yields of callus and anthraquinone in adult rheum, concluding that the anthraquinone metabolites are synthesized via polyketone pathway.
authors.forename: Qi-mei-ge
authors.initials: QM
authors.lastname: Hasi
authors.forename: Hai-ling
authors.initials: HL
authors.lastname: Lj
authors.forename: Yan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Qi-qi-ge
authors.initials: QQ
authors.lastname: Menggen
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D019342:Acetic Acid; D000880:Anthraquinones / Q000737:chemistry*; D019817:Benzoic Acid; D016227:Benzoquinones; D003470:Culture Media / Q000737:chemistry; D007656:Ketoglutaric Acids; D008314:Malonates; D012250:Rheum / Q000737:chemistry*; D012765:Shikimic Acid; D046509:Tissue Culture Techniques
chemical_list: D000880:Anthraquinones; D016227:Benzoquinones; D003470:Culture Media; D007656:Ketoglutaric Acids; D008314:Malonates; C042834:9,10-anthraquinone; D012765:Shikimic Acid; C004532:quinone; D019817:Benzoic Acid; C030290:malonic acid; D019342:Acetic Acid