Synthesis, Formulation, and Adjuvanticity of Monodesmosidic Saponins with Olenanolic Acid, Hederagenin and Gypsogenin Aglycones, and some C-28 Ester Derivatives

Ben W. Greatrex, Alison M. Daines, Sarah Hook, Dirk H. Lenz, Warren McBurney, Thomas Rades, Phillip M. Rendle

Research output: Contribution to journalJournal articleResearchpeer-review

9 Citations (Scopus)

Abstract

In an attempt to discover a new synthetic vaccine adjuvant, the glycosylation of hederagenin, gypsogenin, and oleanolic acid acceptors with di- and trisaccharide donors to generate a range of mimics of natural product QS-21 was carried out. The saponins were formulated with phosphatidylcholine and cholesterol, and the structures analyzed by transmission electron microscopy. 3-O-(Manp(13)Glcp)hederagenin was found to produce numerous ring-like micelles when formulated, while C-28 choline ester derivatives preferred self-assembly and did not interact with the liposomes. When alone and in the presence of cholesterol and phospholipid, the choline ester derivatives produced nanocrystalline rods or helical micelles. The effects of modifying sugar stereochemistry and the aglycone on the immunostimulatory effects of the saponins was then evaluated using the activation markers MHC class II and CD86 in murine bone marrow dendritic cells. The most active saponin, 3-O-(Manp(13)Glcp)hederagenin, was stimulatory at high concentrations in cell culture, but this did not translate to strong responses in vivo.
Original languageEnglish
JournalChemistryOpen
Volume4
Issue number6
Pages (from-to)740-755
Number of pages16
ISSN2191-1363
DOIs
Publication statusPublished - Dec 2015

Keywords

  • carbohydrates
  • glycosylation
  • immunostimulatory effects
  • saponins
  • vaccine adjuvants

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