Hierarchical Self-Assembly of a Renewable Nanosized Pentacyclic Dihydroxy-triterpenoid Betulin Yielding Flower-Like Architectures.

Betulin, a naturally occurring 6-6-6-6-5 pentacyclic dihydroxy-triterpenoid, is extractable from the bark of white birch (Betula papyrifera). We report the first self-assembly properties of betulin in different liquids. The molecule spontaneously self-assembled in different media, yielding flower-like architectures of nano- to micrometers diameters via the formation of fibrillar networks. The self-assemblies have been characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, FTIR, and X-ray diffraction studies. The porous microstructure of the self-assemblies has been utilized for the entrapment of fluorophore such as rhodamine-B and the anticancer drug doxorubicin. Moreover, the removal of toxic dyes such as rhodamine 6G, crystal violet, methylene blue, and cresol red has also been demonstrated.