title: Cytotoxicity of the compounds isolated from Pulsatilla chinensis saponins and apoptosis induced by 23-hydroxybetulinic acid.
abstract: BACKGROUND
  The rizoma of Pulsatilla chinensis (Bunge) Regel has been used as a traditional Chinese medicinal herb for thousands of years. Total saponins from P. chinensis can induce the apoptosis of solid cancer cells; however, their activity on chronic myeloid leukemia and the mechanisms remains unknown.
  
  
  OBJECTIVE
  To study the activity of total saponins and the main active fractions from P. chinensis saponins on chronic myeloid leukemia, and to illustrate the mechanisms underlying the anticancer activities.
  
  
  METHODS
  The cytotoxic activity were assayed by MTT; cell cycle arrest and apoptosis were tested by flow cytometry system; changes in the mitochondrial membrane potential were determined using JC-1; and the apoptosis signaling pathway was determined by western blotting.
  
  
  RESULTS
  We demonstrated that total P. chinensis saponin displayed cytotoxic activity against K562 cell line. In addition, we identified 23-hydroxybetulinic acid (HBA), pulchinenoside A (PA), and anemoside B4 (AB4) from the total saponins, with the most cytotoxic compound HBA. Glycosylation at C3 and C28 of HBA significantly reduces its cytotoxicity. HBA could promote cell cycle arrest at S phase and induce apoptosis via intrinsic pathway. HBA disrupts mitochondrial membrane potential significantly (p < 0.01) and selectively downregulates the levels of Bcl-2, survivin and upregulates Bax, cytochrome C, cleaved caspase-9 and -3.
  
  
  CONCLUSIONS
  Total saponins from P. chinensis may be effective natural products against human chronic myelogenous leukemia; HBA is one of the bioactive components responsible for its anticancer activity, and could be further investigated as an alternative therapeutic drug for leukemia.
authors.affiliation: Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China , Qingdao , China .
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Xingzeng
authors.initials: X
authors.lastname: Zhao
authors.forename: Lin
authors.initials: L
authors.lastname: Xiao
authors.forename: Ge
authors.initials: G
authors.lastname: Liu
authors.forename: Haizhou
authors.initials: H
authors.lastname: Liu
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Wang
authors.forename: Xu
authors.initials: X
authors.lastname: Feng
authors.forename: Xiukun
authors.initials: X
authors.lastname: Lin
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D015394:Molecular Structure; D031946:Pulsatilla / Q000737:chemistry*; D027343:Rhizome / Q000737:chemistry; D016196:S Phase / Q000187:drug effects; D012503:Saponins / Q000737:chemistry*; D014315:Triterpenes / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: C468651:23-hydroxybetulinic acid; D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D012503:Saponins; D014315:Triterpenes
keywords: Cell cycle arrest; K562; chronic myeloid leukemia; intrinsic apoptosis pathway