A booster for vaccines from plants.

The article discusses QS-7, a promising vaccine adjuvant derived from the rare Chilean soapbark tree or Quillaja saponaria. The QS adjuvants belong to a group of secondary metabolites called triterpenoid glycosides or saponins. Due to the complexity of the QS structures, which has challenged traditional chemical synthesis, understanding QS biosynthesis in the native tree presents an opportunity to obtain these pharmaceuticals sustainably.