title: Design, synthesis and biological evaluation of novel betulinic acid derivatives.
abstract: BACKGROUND
  Tumor, is one of the major reason for human death, due to its widespread occurrence. Betulinic acid derivatives have attracted considerable attention as cancer chemopreventive agents and also as cancer therapeutics. Many of its derivatives inhibit the growth of human cancer cell lines by triggering apoptosis. With this background, we planned to synthesize a series of betulinic acid derivatives to assess their antiproliferation efficacy on human cancer cell lines.
  
  
  RESULTS
  A series of novel betulinic acid derivatives were designed and synthesized as highlighted by the preliminary antitumor evaluation against MGC-803, PC3, A375, Bcap-37 and A431 human cancer cell lines in vitro. The pharmacological results showed that some of the compounds displayed moderate to high levels of antitumor activities with most of new exhibiting higher inhibitory activities compared to BA. The IC50 values of compound 3c on the five cancer cell lines were 2.3, 4.6, 3.3, 3.6, and 4.3 μM, respectively. Subsequent fluorescence staining and flow cytometry analysis (FCM) indicated that compound 3c could induce apoptosis in MGC-803 and PC3 cell lines, and the apoptosis ratios reached the peak (37.38% and 33.74%) after 36 h of treatment at 10 μM.
  
  
  CONCLUSIONS
  This study suggests that most of betulinic acid derivatives could inhibit the growth of human cancer cell lines. Furthermore, compound 3c could induce apoptosis of cancer cells.
authors.affiliation: State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, P,R, China. jhzx.msm@gmail.com.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Yang
authors.forename: Na
authors.initials: N
authors.lastname: Liang
authors.forename: Hu
authors.initials: H
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Xue
authors.forename: Deyu
authors.initials: D
authors.lastname: Hu
authors.forename: Linhong
authors.initials: L
authors.lastname: Jin
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhao
authors.forename: Song
authors.initials: S
authors.lastname: Yang