title: Cytotoxic activities of naturally occurring oleanane-, ursane-, and lupane-type triterpenes on HepG2 and AGS cells.
abstract: BACKGROUND
  It is well known that the naturally occurring modified triterpenes in plants have a wide diversity of chemical structures and biological functions. The lupane-, oleanane-, and ursane-type triterpenes are the three major members of natural triterpenes with a wide range of biological properties. A systematic approach is necessary to review their structures and biological activities according to the backbones and the different substituents.
  
  
  OBJECTIVE
  Thirty lupane-(L1-7), oleanane-(O1-14), and ursane-type (U1-9) triterpenes with structural diversity were examined to evaluate their cytotoxic activities against two cancer cell lines, human hepatocellular carcinoma (HepG2) and AGS cells.
  
  
  METHODS
  They were isolated fromHedera helix,Juglans sinensis, andPulsatilla koreanausing a series of column chromatography methods and were treated to evaluate their cytotoxic activities against HepG2 and AGS human gastric adenocarcinoma cell. Further, two triterpenes showing the most potent activities were subjected to the apoptotic screening assay using flow cytometry.
  
  
  RESULTS
  The polar groups, such as an oxo group at C-1, a free hydroxyl at C-2, C-3, or C-23, and a carboxylic moiety at C-28, as well as the type of backbone, explicitly increased the cytotoxic activity on two cancer cells. O5 and U5 showed significantly the potent cytotoxic activity in comparison to other glycosidic triterpenes. In annexin-V/propidium iodide (PI) staining assay, the percentage of late apoptosis (annexin-V+/PI+) 12 and 24 h after treatment with O5 and U5 at 25 μM increased from 14.5% to 93.1% and from 46.4% to 49.1%, respectively, in AGS cells. The cytotoxicity induced by O5 showed a significant difference compared to U5 for 12 and 24 h.
  
  
  CONCLUSIONS
  In the study, we can suggest the potent moieties which influence their cytotoxic activities against two cancer cells. The polar groups at C-1, C-2, C-3, C-23, and C-28 and the linkage of sugar moieties influenced the different cytotoxic activities.
  
  
  CONCLUSIONS
  Thirty naturally occurring oleanane-, ursane-, and lupane-type triterpenes were isolated fromHedera helix,Juglans sinensis, andPulsatilla koreanaAn oxo, a free hydroxyl, a carboxylic moiety, and the types of aglycone influenced the cell cytotoxicityCorosolic acid and α-hederin showed the most potent cytotoxicity via apoptosis.
authors.affiliation: College of Pharmacy, Kangwon National University, Chuncheon, Republic of Korea.
authors.forename: Heejung
authors.initials: H
authors.lastname: Yang
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Kim
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Young Choong
authors.initials: YC
authors.lastname: Kim
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Sung
keywords: Flow cytometry; lupane; oleanane; triterpene; ursane