Electron density study on a saponin from the leaves of Panax notoginseng

Abstract The title saponin, notoginsenoside Fa, consists of a core unit of four annulated rings, a 30 atoms triterpene of steroid type and five sugar substituents, three and two at both core termini. The molecular structure thus exhibits components of different polarity, a non-polar core and five polar sugar substituents. The electron density distribution in this structure was examined, especially local atomic properties in terms of charges and volumes on one hand, and intermolecular interactions such as hydrogen bonds and those based on the electrostatic potential and/or Hirshfeld surfaces on the other hand. The majority of interactions and obviously the potential biological activities originate from the sugars involved in a large number of hydrogen bonds. No interactions of relevance are contributed from the core unit. The interactions and the electronic properties in the differently charged regions were examined.