Synthesis of lupane-type saponins bearing mannosyl and 3,6-branched trimannosyl residues and their evaluation as anticancer agents

Carbohydr Res. 2008 May 5;343(6):995-1003. doi: 10.1016/j.carres.2008.02.011. Epub 2008 Feb 20.

Abstract

The saponins modified with mono- or trimannosyl residues can provide a convenient means of delivering drugs to certain human cells via interactions with mannose receptors. In the study reported therein, we developed a convenient approach for the synthesis of 3-O-mannoside and branched trimannoside derivatives of the saponin lupeol and of C-28 acyl esters of 3-O-acetyl-betulinic acid bearing the same mannosyl entities. Lupeol and 3-O-acetyl-betulinic acid were mannosylated with tetra-O-benzoyl- or tetra-O-acetyl-alpha-D-mannopyranosyl trichloroacetimidates. De-esterification followed by regioselective dimannosylation of the unprotected monosaccharide derivatives with 2equiv of tetra-O-benzoyl-alpha-D-mannopyranosyl trichloroacetimidate selectively yielded O-3,O-6-linked trimannosides. The cytotoxic activity of selected lupane-type saponins (derivatives of lupeol, betulinic acid, and betulin) toward normal human fibroblasts and various cancer cell lines was also compared.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / pharmacology
  • Betulinic Acid
  • Cell Survival / drug effects
  • Cells, Cultured
  • Fibroblasts / drug effects
  • Humans
  • Mannose / chemistry*
  • Mannosides / chemistry*
  • Molecular Structure
  • Neoplasms / drug therapy
  • Pentacyclic Triterpenes
  • Saponins / chemical synthesis*
  • Saponins / pharmacology
  • Triterpenes / chemistry*

Substances

  • Antineoplastic Agents
  • Mannosides
  • Pentacyclic Triterpenes
  • Saponins
  • Triterpenes
  • betulin
  • lupeol
  • Mannose
  • Betulinic Acid